Pyothorax in Cats: A Review - VCA Specialty Animal Hospitals

Pyothorax in Cats: A Review - VCA Specialty Animal Hospitals Pyothorax in Cats: A Review - VCA Specialty Animal Hospitals

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Pyothorax is defined as an accumulation of purulent material in the pleural space. Infection may be introduced from the chest wall, diaphragm, lung parenchyma, esophagus, or airways. The most common cause of feline pyothorax has long been thought to be bite wounds to the chest from other cats, but recent evidence points to another major cause: the transmission of infection from the lungs. 1 Other reported causes include aberrant migration of Cuterebra, penetrating foreign body, hematogenous or lymphatic diffusion of distant infection, esophageal or tracheal perforation, pulmonary abscess, lung parasites, discospondylitis, neoplasia with abscess, and iatrogenic infection. 1-3 Cats with pyothorax often present with general signs of malaise such as lethargy and decreased appetite. Tachypnea, coughing, and weight loss may be reported and some animals will be dyspneic. Symptoms such as hypersalivation and bradycardia have been associated with a worse outcome. 2 On physical examination, the majority of patients will be febrile. Auscultation may reveal ventrally quiet lung sounds, unilaterally or bilaterally. Wounds may be present over the chest but this is a rare finding. A complete, attentive physical examination is recommended as multisystemic findings may help direct the diagnostic and therapeutic approach. Volume 1, Issue 4 j March/April 2011 Pyothorax in Cats: A Review Valérie Sauvé, DVM, DACVECC Fifth Avenue Veterinary Specialists Orthogonal thoracic radiographs should be obtained to confirm pleural effusion and to determine if the fluid accumulation is bilateral or unilateral. Radiographs may also reveal underlying conditions such as a mass or abscess and should be carefully reviewed for evidence supporting other differential diagnoses. Diagnostic or therapeutic thoracocentesis (usually while the patient is under sedation) is recommended. Any effusion of unknown cause in the chest should be sampled for fluid analysis and cytology unless congestive heart failure is suspected. If this is the case and there is only a small amount of effusion, a diagnostic thoracocentesis may be delayed pending response to treatment with a diuretic. Patients with pyothorax will have an exudative effusion featuring both a high WBC count and total solids (>3.0 g/dL). Cytology of the effusion can be performed in house but should also be submitted to a clinical pathologist for review, as filamentous bacteria and neoplastic cells may be more difficult to identify. The cytology of pyothorax fluid will typically show degenerative neutrophils and intracellular and/or extracellular bacteria. Ideally, cultures should be submitted, both aerobic and anaerobic, on all patients before the commencement of antibiotic therapy. Anaerobes with or without aerobic bacteria are most commonly involved. Acid fast testing on bacterial isolate may be helpful if filamentous bacteria are present in the sample. If positive, TMS should be added to the antibiotics. Blood tests and advanced imaging techniques can be used to investigate the cause of the pyothorax and to help the clinician in discussing prognosis with the owners. Baseline testing including CBC, biochemistry, and FeLV/FIV is recommended. Patients with higher WBC counts have been found to have a better outcome. 2 FIP PCR of the effusion may be indicated. Toxoplasmosis IgG/IgM and Cryptococcus AG may be performed if parenchymal lung disease is present. Abdominal ultrasound can be used to look for other organ system involvement and thoracic ultrasound may identify masses, abscesses, or pocketed fluid accumulation. Ultrasound is also very useful in guiding thoracocentesis in patients with a small amount of effusion. Thoracic computed tomography (CT scan) may become more commonly performed in the future to determine the underlying disease and need for surgical exploration. Treatment is mostly focused on draining the infection. Repeated thoracocenteses are associated with poor outcome and cannot be recommended. Unilateral but usually bilateral chest tubes should be placed as soon as the patient is stable. Performing a therapeutic thoracocentesis and administering IV fluids and oxygen prior to general anesthesia is Continued on page 2

<strong>Pyothorax</strong> is def<strong>in</strong>ed as an accumulation<br />

of purulent material <strong>in</strong> the pleural<br />

space. Infection may be <strong>in</strong>troduced<br />

from the chest wall, diaphragm, lung<br />

parenchyma, esophagus, or airways. The<br />

most common cause of fel<strong>in</strong>e pyothorax<br />

has long been thought to be bite wounds<br />

to the chest from other cats, but recent<br />

evidence po<strong>in</strong>ts to another major cause: the<br />

transmission of <strong>in</strong>fection from the lungs. 1<br />

Other reported causes <strong>in</strong>clude aberrant<br />

migration of Cuterebra, penetrat<strong>in</strong>g foreign<br />

body, hematogenous or lymphatic diffusion<br />

of distant <strong>in</strong>fection, esophageal or tracheal<br />

perforation, pulmonary abscess, lung<br />

parasites, discospondylitis, neoplasia with<br />

abscess, and iatrogenic <strong>in</strong>fection. 1-3<br />

<strong>Cats</strong> with pyothorax often present with<br />

general signs of malaise such as lethargy and<br />

decreased appetite. Tachypnea, cough<strong>in</strong>g,<br />

and weight loss may be reported and some<br />

animals will be dyspneic. Symptoms such as<br />

hypersalivation and bradycardia have been<br />

associated with a worse outcome. 2 On physical<br />

exam<strong>in</strong>ation, the majority of patients will be<br />

febrile. Auscultation may reveal ventrally<br />

quiet lung sounds, unilaterally or bilaterally.<br />

Wounds may be present over the chest but<br />

this is a rare f<strong>in</strong>d<strong>in</strong>g. A complete, attentive<br />

physical exam<strong>in</strong>ation is recommended as<br />

multisystemic f<strong>in</strong>d<strong>in</strong>gs may help direct the<br />

diagnostic and therapeutic approach.<br />

Volume 1, Issue 4 j March/April 2011<br />

<strong>Pyothorax</strong> <strong>in</strong> <strong>Cats</strong>: A <strong>Review</strong><br />

Valérie Sauvé, DVM, DACVECC<br />

Fifth Avenue Veter<strong>in</strong>ary Specialists<br />

Orthogonal thoracic radiographs should be<br />

obta<strong>in</strong>ed to confirm pleural effusion and<br />

to determ<strong>in</strong>e if the fluid accumulation is<br />

bilateral or unilateral. Radiographs may also<br />

reveal underly<strong>in</strong>g conditions such as a mass<br />

or abscess and should be carefully reviewed<br />

for evidence support<strong>in</strong>g other differential<br />

diagnoses. Diagnostic or therapeutic<br />

thoracocentesis (usually while the patient<br />

is under sedation) is recommended. Any<br />

effusion of unknown cause <strong>in</strong> the chest<br />

should be sampled for fluid analysis and<br />

cytology unless congestive heart failure is<br />

suspected. If this is the case and there is<br />

only a small amount of effusion, a diagnostic<br />

thoracocentesis may be delayed pend<strong>in</strong>g<br />

response to treatment with a diuretic.<br />

Patients with pyothorax will have an exudative<br />

effusion featur<strong>in</strong>g both a high WBC count and<br />

total solids (>3.0 g/dL). Cytology of the effusion<br />

can be performed <strong>in</strong> house but should also be<br />

submitted to a cl<strong>in</strong>ical pathologist for review, as<br />

filamentous bacteria and neoplastic cells may<br />

be more difficult to identify. The cytology of<br />

pyothorax fluid will typically show degenerative<br />

neutrophils and <strong>in</strong>tracellular and/or extracellular<br />

bacteria. Ideally, cultures should be submitted,<br />

both aerobic and anaerobic, on all patients<br />

before the commencement of antibiotic therapy.<br />

Anaerobes with or without aerobic bacteria are<br />

most commonly <strong>in</strong>volved. Acid fast test<strong>in</strong>g on<br />

bacterial isolate may be helpful if filamentous<br />

bacteria are present <strong>in</strong> the sample. If positive,<br />

TMS should be added to the antibiotics.<br />

Blood tests and advanced imag<strong>in</strong>g techniques<br />

can be used to <strong>in</strong>vestigate the cause of<br />

the pyothorax and to help the cl<strong>in</strong>ician <strong>in</strong><br />

discuss<strong>in</strong>g prognosis with the owners. Basel<strong>in</strong>e<br />

test<strong>in</strong>g <strong>in</strong>clud<strong>in</strong>g CBC, biochemistry, and<br />

FeLV/FIV is recommended. Patients with<br />

higher WBC counts have been found to have<br />

a better outcome. 2 FIP PCR of the effusion<br />

may be <strong>in</strong>dicated. Toxoplasmosis IgG/IgM<br />

and Cryptococcus AG may be performed<br />

if parenchymal lung disease is present.<br />

Abdom<strong>in</strong>al ultrasound can be used to look for<br />

other organ system <strong>in</strong>volvement and thoracic<br />

ultrasound may identify masses, abscesses,<br />

or pocketed fluid accumulation. Ultrasound<br />

is also very useful <strong>in</strong> guid<strong>in</strong>g thoracocentesis<br />

<strong>in</strong> patients with a small amount of effusion.<br />

Thoracic computed tomography (CT scan)<br />

may become more commonly performed <strong>in</strong><br />

the future to determ<strong>in</strong>e the underly<strong>in</strong>g disease<br />

and need for surgical exploration.<br />

Treatment is mostly focused on dra<strong>in</strong><strong>in</strong>g<br />

the <strong>in</strong>fection. Repeated thoracocenteses are<br />

associated with poor outcome and cannot be<br />

recommended. Unilateral but usually bilateral<br />

chest tubes should be placed as soon as the<br />

patient is stable. Perform<strong>in</strong>g a therapeutic<br />

thoracocentesis and adm<strong>in</strong>ister<strong>in</strong>g IV fluids<br />

and oxygen prior to general anesthesia is<br />

Cont<strong>in</strong>ued on page 2


<strong>Pyothorax</strong> <strong>in</strong> <strong>Cats</strong> Cont<strong>in</strong>ued from page 1<br />

beneficial to make the patient more stable<br />

for placement. Patients with thoracostomy<br />

tubes need to be monitored 24 hours a day<br />

because disconnection can cause a severe<br />

pneumothorax. If the fluid is thick, flush<strong>in</strong>g<br />

the tubes with sterile sal<strong>in</strong>e may be beneficial<br />

as this will help to dislodge the purulent<br />

material. Approximately 10 mL/kg of sterile<br />

warm NaCl 0.9% is slowly <strong>in</strong>fused, the animal<br />

is turned and rotated and then the fluid is<br />

removed. This can be performed 2-4 times<br />

per day. It is important to note the amount<br />

of fluid flushed and retrieved as the <strong>in</strong>flamed<br />

pleura may reabsorb fluid and this needs to be<br />

accounted for <strong>in</strong> the IV fluids plan.<br />

Supportive care is also essential for the<br />

recovery of these patients. Intravenous<br />

fluids are needed as well as parenteral pa<strong>in</strong><br />

medication. A fentanyl/ketam<strong>in</strong>e CRI is<br />

often used for analgesia as the chest tubes<br />

are pa<strong>in</strong>ful. Intravenous antibiotics are also<br />

<strong>in</strong>dicated. Broad spectrum antibiotics are used<br />

while await<strong>in</strong>g culture results, and anaerobic<br />

coverage is mandatory. The comb<strong>in</strong>ation<br />

of enrofloxac<strong>in</strong> and ampicill<strong>in</strong>-sulbactam<br />

is usually the first l<strong>in</strong>e. Respiratory support<br />

such as bronchodilators, nebulization, and<br />

oxygen therapy may also be needed, and<br />

electrolytes and nutritional <strong>in</strong>take should be<br />

carefully monitored.<br />

The majority of patients will require an<br />

average of 4-6 days of treatment before the<br />

chest tubes can be removed. Exploratory<br />

thoracotomy or thoracoscopy may benefit<br />

some patients with compartmentalized fluid<br />

or a poor response to medical treatment,<br />

and early surgical <strong>in</strong>tervention is <strong>in</strong>dicated<br />

<strong>in</strong> those patients with a thoracic wall<br />

lesion, <strong>in</strong>trathoracic mass, foreign body, or<br />

perforated esophagus. In human patients,<br />

biochemical values such as glucose, pH, and<br />

lactate are used to determ<strong>in</strong>e the need for<br />

<strong>in</strong>vasive treatment, however this has not been<br />

studied <strong>in</strong> animals. A CT scan may be useful<br />

<strong>in</strong> plann<strong>in</strong>g a surgical approach. Antibiotic<br />

therapy should be cont<strong>in</strong>ued for 4-6 weeks,<br />

end<strong>in</strong>g 1-2 weeks after complete resolution<br />

of radiographic changes.<br />

The prognosis for cats with pyothorax<br />

treated as <strong>in</strong>patients with thoracostomy tubes<br />

is fair to good, with a favorable outcome<br />

reported <strong>in</strong> 66-95% of cases. 1-3 Thoracotomy<br />

was required only <strong>in</strong> a m<strong>in</strong>ority of pets <strong>in</strong><br />

published studies, and the need for surgery<br />

was not <strong>in</strong>dicative of a worse prognosis. j<br />

2<br />

Case <strong>Review</strong>: Luna<br />

Luna is a 12 year old DSH who presented to FAVS’<br />

cardiology service for evaluation of pleural effusion.<br />

She had a history of weight loss, <strong>in</strong>appetence and<br />

lethargy for several weeks. Her blood work at Gramercy<br />

Park <strong>Animal</strong> Hospital showed severe neutrophilia<br />

with a left shift. She received enrofloxac<strong>in</strong> for two<br />

weeks which improved her cl<strong>in</strong>ical signs, but her<br />

neutrophilia was persistent and she began to decl<strong>in</strong>e<br />

once the antibiotics were discont<strong>in</strong>ued. She had also developed vomit<strong>in</strong>g and mild dyspnea.<br />

Lateral and v/d images show<strong>in</strong>g Luna’s<br />

pleural effusion and chest tube placement.<br />

Luna with her bilateral<br />

thoracostomy tubes.<br />

An echocardiogram showed Luna’s cardiac structure and function<br />

to be normal. Our cardiologist, Dr. Sophy Jesty, performed a<br />

diagnostic thoracentesis under sedation which revealed a<br />

septic suppurative exudate. Luna was then transferred to the<br />

Critical Care service. She received <strong>in</strong>travenous fluids, <strong>in</strong>clud<strong>in</strong>g<br />

Hetastarch, to address her hypotension and dehydration<br />

overnight, and started antibiotic therapy. Her clott<strong>in</strong>g times were<br />

prolonged therefore she received fresh frozen plasma and vitam<strong>in</strong><br />

K1. Her oxygen saturation was with<strong>in</strong> normal limits so she did<br />

not require oxygen supplementation. Luna’s CBC showed that the<br />

neutrophilia and left shift had worsened significantly but she was<br />

afebrile. Bacterial cultures of the pleural effusion were negative<br />

although the fluid analysis and cytology were confirmatory for<br />

pyothorax. The next day bilateral thoracostomy tubes<br />

were placed with Luna under general anesthesia.<br />

The right-sided tube was removed after 7 days. The last radiographs of<br />

her stay showed persistent right sided <strong>in</strong>filtrates. She was discharged on<br />

amoxicill<strong>in</strong>-clavulanic acid and enrofloxac<strong>in</strong> orally.<br />

At the first recheck, Luna unfortunately had persistent unilateral pleural<br />

effusion. Thoracocentesis revealed a low- to moderate-grade chronic-active<br />

suppurative <strong>in</strong>flammation. FIP PCR was negative. However, her WBC count was<br />

improv<strong>in</strong>g and she was do<strong>in</strong>g very well at home, ga<strong>in</strong><strong>in</strong>g weight and hav<strong>in</strong>g a<br />

good appetite. The owners decl<strong>in</strong>ed CT and exploratory thoracotomy and elected<br />

to cont<strong>in</strong>ue oral antibiotics. Luna was then rechecked at Gramercy Park <strong>Animal</strong><br />

Hospital by Dr. Karen Feibusch and her radiographs and CBC normalized after<br />

8 weeks of antibiotics. Four months after her stay at our hospital, she is do<strong>in</strong>g<br />

wonderfully at home!<br />

Luna at home a few months after her stay!<br />

Luna rema<strong>in</strong>ed <strong>in</strong> the hospital for 7 days, receiv<strong>in</strong>g<br />

IV enrofloxac<strong>in</strong>, ampicill<strong>in</strong>-sulbactam, famotid<strong>in</strong>e,<br />

and a ketam<strong>in</strong>e/fentanyl CRI. She also benefited from<br />

nasogastric Cl<strong>in</strong>icare feed<strong>in</strong>gs. The tubes were <strong>in</strong>itially<br />

flushed 3 times per day with 10 ml/kg of warm sterile<br />

sal<strong>in</strong>e. The left-sided tube was removed after 4 days<br />

as it was no longer productive and the left lung was<br />

completely normal on<br />

follow-up radiographs.<br />

References and recommended read<strong>in</strong>g<br />

1 Barrs VR. Fel<strong>in</strong>e pyothorax: a retrospective study of 27 cases <strong>in</strong> Australia. J Fel<strong>in</strong>e Med Surg<br />

2005;7(4):211-222.<br />

2 Waddell LS et al. Risk factors, prognostic <strong>in</strong>dicators, and outcome of pyothorax <strong>in</strong> cats: 80<br />

cases (1986-1999). J Am Vet Med Assoc 2002;221(6):819-824.<br />

3 MacPhail CM. Medical and Surgical Management of <strong>Pyothorax</strong>. Vet Cl<strong>in</strong> North Am Small<br />

Anim Pract. 2007;37(5):975-988, viii.<br />

Full Circle Forum


a 3 year old, 33 kg, <strong>in</strong>tact<br />

male Labrador Retriever was<br />

“Dusty,”<br />

presented for evaluation of<br />

suspected ivermect<strong>in</strong> toxicity. He was seen<br />

<strong>in</strong>gest<strong>in</strong>g approximately 600 mg of an equ<strong>in</strong>e<br />

ivermect<strong>in</strong> 1.87% paste 12 hours prior to<br />

presentation (maximum dose of 18 mg/kg<br />

ivermect<strong>in</strong>). Initial physical exam revealed<br />

bradycardia (HR=70 bpm), bl<strong>in</strong>dness, mild<br />

tremors, vocalization, hypersalivation and<br />

severe pelvic limb ataxia. The dog was<br />

disoriented, agitated, and runn<strong>in</strong>g <strong>in</strong>to walls.<br />

Further neurologic exam<strong>in</strong>ation revealed<br />

mydriasis, absent menace, and absent pupillary<br />

light reflexes (direct and consensual) bilaterally,<br />

along with conscious proprioceptive deficits <strong>in</strong><br />

the pelvic limbs. Dusty was unable to navigate<br />

a maze or track a cotton ball.<br />

Diagnostic tests <strong>in</strong>cluded a serum chemistry<br />

and complete blood count which were both<br />

unremarkable. Gastric empty<strong>in</strong>g procedures were<br />

not pursued due to the time delay between <strong>in</strong>gestion<br />

and admission (12 hours). Anecdotal evidence<br />

of successful treatment of can<strong>in</strong>e ivermect<strong>in</strong><br />

toxicosis with the novel therapy of <strong>in</strong>travenous<br />

lipid emulsion (ILE) adm<strong>in</strong>istration has been<br />

documented. Based on this evidence we elected<br />

to treat the dog with <strong>in</strong>travenous fat emulsion<br />

(Liposyn II 20%) one hour post admission.<br />

Dusty was given a 1.5 mL/kg <strong>in</strong>travenous bolus<br />

of Liposyn followed by a constant rate <strong>in</strong>fusion<br />

of 0.25 mL/kg/m<strong>in</strong> for sixty m<strong>in</strong>utes.<br />

Post-lipid emulsion therapy, Dusty’s pupillary<br />

light reflexes were markedly improved and he<br />

was able to navigate a maze and track cotton<br />

balls. He also had mild improvement <strong>in</strong> the<br />

pelvic limb ataxia. The dog was also treated<br />

with 1g/kg of activated charcoal (Toxiban with<br />

Sorbitol) orally. He was discharged 6 hours<br />

post admission due to f<strong>in</strong>ancial constra<strong>in</strong>ts and<br />

was sent home with three additional doses of<br />

activated charcoal without sorbitol to be given<br />

every 6 hours. Dusty was reported by the family<br />

to be cl<strong>in</strong>ically normal 12 hours after <strong>in</strong>itial<br />

presentation (24 hours post <strong>in</strong>gestion).<br />

A toxicology panel was submitted for macrolide<br />

endectocides and reported a positive serum<br />

ivermect<strong>in</strong> level of 2540 ppb prior to lipid<br />

<strong>in</strong>fusion. Immediately follow<strong>in</strong>g lipid <strong>in</strong>fusion,<br />

Case Report: Ivermect<strong>in</strong> Toxicity and<br />

Treatment with Lipid Emulsions<br />

Melissa L. Holahan, DVM, DACVECC<br />

<strong>VCA</strong> Shorel<strong>in</strong>e Veter<strong>in</strong>ary Referral & Emergency Center<br />

the ivermect<strong>in</strong> level was less than 30 ppb. This<br />

case report is the first to document ivermect<strong>in</strong><br />

levels pre- and post-lipid emulsion therapy. These<br />

results provide further evidence that lipid emulsion<br />

therapy may be valuable <strong>in</strong> the <strong>in</strong>itial treatment<br />

of ivermect<strong>in</strong> toxicity. Its use is also supported by<br />

recent case studies <strong>in</strong>volv<strong>in</strong>g treatment of various<br />

toxicities <strong>in</strong>clud<strong>in</strong>g avermect<strong>in</strong>s. 1,2<br />

Ivermect<strong>in</strong> is a broad-spectrum antiparasitic drug<br />

commonly used aga<strong>in</strong>st nematode <strong>in</strong>festations<br />

and external parasites. Ivermect<strong>in</strong> is licensed for<br />

use <strong>in</strong> cats and dogs as heartworm prevention.<br />

Dogs can develop cl<strong>in</strong>ical signs of ivermect<strong>in</strong><br />

toxicity at doses >2.5 mg/kg from accidental use<br />

or <strong>in</strong>gestion of equ<strong>in</strong>e or livestock deworm<strong>in</strong>g<br />

products. Collies and other herd<strong>in</strong>g dogs are<br />

more sensitive to ivermect<strong>in</strong> toxicity due to<br />

potential deficiencies <strong>in</strong> one of the MDR1-type<br />

P-glycoprote<strong>in</strong>s. 3 Toxicity has also been reported<br />

<strong>in</strong> other breeds and cats at approved labeled doses.<br />

Other avermect<strong>in</strong>s that have similar mechanisms<br />

of action and toxicity <strong>in</strong>clude moxidect<strong>in</strong>,<br />

epr<strong>in</strong>omect<strong>in</strong>, selamect<strong>in</strong>, and doramect<strong>in</strong>.<br />

Ivermect<strong>in</strong> is an agonist of <strong>in</strong>vertebratespecific,<br />

glutamate-activated, <strong>in</strong>hibitory<br />

chloride channels caus<strong>in</strong>g flaccid paralysis and<br />

subsequent death <strong>in</strong> nematodes and mites. The<br />

toxic effects seen <strong>in</strong> mammals after ivermect<strong>in</strong><br />

<strong>in</strong>gestion are due to the similarity of the<br />

<strong>in</strong>vertebrate-specific channels to the vertebrate<br />

γ-am<strong>in</strong>obutyric acid (GABA )-gated channels<br />

A<br />

that <strong>in</strong>hibit <strong>in</strong>terneurons <strong>in</strong> the central nervous<br />

system. At therapeutic doses, the blood-bra<strong>in</strong><br />

barrier protects aga<strong>in</strong>st these effects. At high<br />

doses, ivermect<strong>in</strong> potentiates these channels<br />

caus<strong>in</strong>g hyperpolarization of cell membranes,<br />

thus prevent<strong>in</strong>g neuronal depolarization. 4<br />

Cl<strong>in</strong>ical signs reported with ivermect<strong>in</strong> toxicity<br />

<strong>in</strong>clude ataxia, vocalization, disorientation,<br />

hyperesthesia, bl<strong>in</strong>dness, weakness, mydriasis,<br />

and bradycardia. Severe cases may develop<br />

seizures, generalized weakness, respiratory<br />

depression, stupor or coma. Signs may manifest<br />

as early as 2-4 hours post-<strong>in</strong>gestion but may<br />

be delayed up to 24 hours. These signs can<br />

also progress for 5-7 days post-exposure and<br />

patients should be observed closely dur<strong>in</strong>g this<br />

time. Diagnosis is typically based on witnessed<br />

or suspected <strong>in</strong>gestion of ivermect<strong>in</strong>. If the<br />

patient’s exposure is unknown, other tox<strong>in</strong>s such<br />

as carbamate and organophosphate <strong>in</strong>secticides,<br />

tremorogenic mycotox<strong>in</strong>s, sedatives or muscle<br />

relaxants should be considered. A macrolide<br />

endectocides toxicology panel can be requested<br />

through the California <strong>Animal</strong> Health &<br />

Food Safety Laboratory System to test for<br />

avermect<strong>in</strong>s if suspected.<br />

Gastric decontam<strong>in</strong>ation is the first step <strong>in</strong><br />

treatment unless contra<strong>in</strong>dicated (lack of gag,<br />

decreased mentation); follow-up therapy is<br />

largely supportive. Repeated doses of activated<br />

charcoal should be adm<strong>in</strong>istered due to<br />

enterohepatic recirculation. Those patients that<br />

are symptomatic may require anticonvulsant<br />

therapy. Diazepam and other benzodiazep<strong>in</strong>es<br />

are believed to potentiate the effects of ivermect<strong>in</strong><br />

and prolong recovery due to their GABAenhanc<strong>in</strong>g<br />

properties. 5,6 Alternative drugs for<br />

anticonvulsant therapy <strong>in</strong>clude phenobarbital<br />

and propofol. Patients that are stuporous or<br />

comatose should be monitored closely to ensure<br />

that they have a gag reflex and can ma<strong>in</strong>ta<strong>in</strong><br />

their airway. Those patients that have lost their<br />

gag reflex or become hypercapnic may require<br />

endotracheal <strong>in</strong>tubation and ventilator support.<br />

Anecdotal evidence has suggested that ILEs may<br />

be a promis<strong>in</strong>g antidote for ivermect<strong>in</strong> toxicity. 7<br />

ILEs such as Liposyn II (20% soybean oil, 1.2%<br />

egg phosphatides and 2.5% glycer<strong>in</strong> <strong>in</strong> water for<br />

<strong>in</strong>jection) are traditionally used as a component of<br />

parenteral nutrition therapy and have a 1 year shelf<br />

life. Possible acute risks of short-term ILE therapy<br />

<strong>in</strong>clude thrombophlebitis dur<strong>in</strong>g peripheral IV<br />

adm<strong>in</strong>istration, anaphylaxis, and fat emboli.<br />

However, ILEs have a very safe track record<br />

based on their frequent and longstand<strong>in</strong>g use <strong>in</strong><br />

parenteral nutrition therapy <strong>in</strong> critically ill patients.<br />

One proposed mechanism of lipid therapy is<br />

that the exogenous lipid provides an alternative<br />

source for b<strong>in</strong>d<strong>in</strong>g of lipid soluble drugs,<br />

<strong>in</strong>clud<strong>in</strong>g local anesthetics and avermect<strong>in</strong>s. 8<br />

This “lipid s<strong>in</strong>k” theory holds that lipophilic<br />

drug molecules (such as ivermect<strong>in</strong>) shift <strong>in</strong>to<br />

a lipemic plasma compartment mak<strong>in</strong>g them<br />

unavailable to the tissue. Other proposed<br />

mechanisms <strong>in</strong>clud<strong>in</strong>g <strong>in</strong>creased metabolism,<br />

distribution, or partition of drug molecules away<br />

from receptors <strong>in</strong>to lipids with<strong>in</strong> the tissues. 8<br />

Cont<strong>in</strong>ued on page 4<br />

March/April 2011 3


Ivermect<strong>in</strong> Toxicity & Treatment w/ Lipid Emulsions Cont<strong>in</strong>ued from page 3<br />

Lipid emulsions may also have a role <strong>in</strong> the<br />

treatment of permethr<strong>in</strong> toxicosis due its high<br />

lipid partition coefficient but currently no cases<br />

have been reported <strong>in</strong> veter<strong>in</strong>ary medic<strong>in</strong>e.<br />

Dosages of <strong>in</strong>travenous lipid emulsions (such<br />

as 20% Intralipid) are extrapolated from<br />

human medic<strong>in</strong>e: 1.5 mL/kg as an <strong>in</strong>itial<br />

bolus, followed by 0.25 mL/kg/m<strong>in</strong> for 30-<br />

60 m<strong>in</strong>utes. Boluses could be repeated 1-2<br />

4<br />

times with a maximum total dose of 8 mL/<br />

kg recommended. Although standards for the<br />

optimal and maximal doses to be given, the<br />

appropriate rate of adm<strong>in</strong>istration, and the<br />

duration of therapy have not been established<br />

<strong>in</strong> veter<strong>in</strong>ary medic<strong>in</strong>e, the anecdotal evidence<br />

of us<strong>in</strong>g lipid emulsion therapy early <strong>in</strong><br />

ivermect<strong>in</strong> toxicity is encourag<strong>in</strong>g.<br />

In summary, <strong>in</strong>travenous lipid therapy is a novel<br />

treatment approach for ivermect<strong>in</strong> toxicity. Its use<br />

is supported by recent research and case studies<br />

<strong>in</strong>volv<strong>in</strong>g lipid adm<strong>in</strong>istration for bupivaca<strong>in</strong>e 8<br />

and other fat-soluble tox<strong>in</strong>s. Lipid adm<strong>in</strong>istration<br />

<strong>in</strong> this case appeared to reverse the dog’s cl<strong>in</strong>ical<br />

signs and markedly decreased the ivermect<strong>in</strong> level<br />

present <strong>in</strong> the serum. This therapy may also prove<br />

to be beneficial with other fat-soluble tox<strong>in</strong>s, such<br />

as beta-blockers and permethr<strong>in</strong>s. j<br />

References:<br />

1 Crandell DE, We<strong>in</strong>berg GL. Moxidect<strong>in</strong> toxicosis <strong>in</strong> a puppy successfully treated with <strong>in</strong>travenous lipids. J of Vet Crit Care. 2009;19:181-186.<br />

2 O’Brien TQ, Clark-Price SC, Evans EE, DiFazio R, McMichael MA. Infusion of a lipid emulsion to treat lidoca<strong>in</strong>e <strong>in</strong>toxication <strong>in</strong> a cat. J Am Vet Med<br />

Assoc. 2010;237(12):1455-1458.<br />

3 Mealey KL, Bentjen SA, Gay JM, Cantor GH. Ivermect<strong>in</strong> sensitivity <strong>in</strong> Collies is associated with a deletion mutation of the MDR1 gene. Pharmacoge-<br />

netics. 2001;11(8):727–733.<br />

4 Peterson ME, Talcott PA. Small <strong>Animal</strong> Toxicology, 2nd ed. Philadelphia:WB Saunders, 2006.<br />

5 Williams M, Risley EA. Ivermect<strong>in</strong> <strong>in</strong>teractions with benzodiazep<strong>in</strong>e receptors <strong>in</strong> rat cortex and cerebellum <strong>in</strong> vitro. J Neurochem. 1984;42(3):745–753.<br />

6 Williams M, Yarbrough GG. Enhancement of <strong>in</strong> vitro b<strong>in</strong>d<strong>in</strong>g and some of the pharmacological properties of diazepam by a novel anthelm<strong>in</strong>tic agent,<br />

avermect<strong>in</strong> B1a. Eur J Pharmacol. 1979;56(3):273–276.<br />

7 LipidRescue Web site. Available at: www.lipidrescue.org. Accessed January 24, 2011.<br />

8 We<strong>in</strong>berg G, Ripper R, Fe<strong>in</strong>ste<strong>in</strong> DL, Hoffman W. Lipid emulsion <strong>in</strong>fusion rescues dogs from bupivaca<strong>in</strong>e-<strong>in</strong>duced cardiac toxicity. Reg Anesth Pa<strong>in</strong><br />

Med. 2003;28(3):198-202.<br />

Referr<strong>in</strong>g Veter<strong>in</strong>arians As Partners<br />

Dermatophytosis, Drug Resistant Superficial<br />

Pyoderma, and Atopic Dermatitis <strong>in</strong> a Dog<br />

Jeanne Budg<strong>in</strong>, DVM, DACVD, <strong>Animal</strong> <strong>Specialty</strong> Center, and Patricia Doherty, DVM<br />

a 7 year old spayed female<br />

Vizsla, <strong>in</strong>itially presented to Dr. Patricia<br />

“Sophie,”<br />

Doherty with a four year history of<br />

pruritic, non-seasonal sk<strong>in</strong> disease. A previous<br />

blood allergy panel (HESKA Allercept) had<br />

been performed and revealed positive reactions<br />

to house dust mites, storage mites, several molds,<br />

and one tree. Allergen specific immunotherapy<br />

(ASIT) had been adm<strong>in</strong>istered for a two<br />

year period without improvement and was<br />

subsequently discont<strong>in</strong>ued. The sk<strong>in</strong> condition<br />

had improved with prednisone therapy <strong>in</strong> the<br />

past, however unacceptable side effects <strong>in</strong>clud<strong>in</strong>g<br />

marked polyuria, polydipsia, and polyphagia were<br />

reported. Dr. Doherty had recently prescribed<br />

oral Atopica at 5.3 mg/kg every 24 hours and<br />

recommended a food elim<strong>in</strong>ation dietary trial<br />

with Hill’s z/d Ultra to evaluate for an adverse<br />

reaction to food. One month after <strong>in</strong>itiat<strong>in</strong>g<br />

treatment with Atopica, new, mildly pruritic sk<strong>in</strong><br />

lesions consist<strong>in</strong>g of multifocal annular patches of<br />

alopecia, erythema, and scale were present on the<br />

convex p<strong>in</strong>nae and paralumbar area. Dr. Doherty<br />

performed a deep sk<strong>in</strong> scrap<strong>in</strong>g (negative),<br />

collected a fungal (DTM) culture, and <strong>in</strong>itiated<br />

oral antibiotic therapy (cephalex<strong>in</strong>, 26 mg/kg<br />

every 12 hours x 21 days). After two weeks, the<br />

fungal culture was positive for Microsporum canis.<br />

The Atopica was lowered to 5.3 mg/kg every 48<br />

hours; twice weekly KetoChlor shampoo and<br />

twice daily 1% miconazole lotion were prescribed.<br />

Though the sk<strong>in</strong> lesions <strong>in</strong>itially improved,<br />

Sophie cont<strong>in</strong>ued to develop new lesions and was<br />

referred to the Dermatology and Allergy Service<br />

at <strong>Animal</strong> <strong>Specialty</strong> Center.<br />

Our dermatological evaluation yielded several<br />

f<strong>in</strong>d<strong>in</strong>gs. There were patches of alopecia with<br />

adherent white scale and <strong>in</strong>creased epilation near<br />

the right medial canthus, surround<strong>in</strong>g the base of<br />

each ear, and cover<strong>in</strong>g the convex aspects of both<br />

p<strong>in</strong>nae. There were multiple papules and heavy<br />

yellow crust on the concave aspect of the right<br />

p<strong>in</strong>na, and the lateral aspects of the muzzle, dorsal<br />

head, medial left forelimb, lateral thorax, and<br />

flanks exhibited mutifocal papules and plaques<br />

with f<strong>in</strong>e surface scale. Sk<strong>in</strong> cytology via acetate<br />

tape preparation revealed no significant f<strong>in</strong>d<strong>in</strong>gs<br />

and flea comb<strong>in</strong>g was negative. Wood’s lamp<br />

exam<strong>in</strong>ation was positive <strong>in</strong> multiple sites. Sophie’s<br />

assessment was generalized dermatophytosis<br />

due to M. canis. The history of glucocorticoidresponsive<br />

dermatosis, as well as the results of the<br />

previous blood allergy panel, supported atopic<br />

dermatitis but due to the non-seasonal nature<br />

of disease, an adverse reaction to food could not<br />

be ruled out. The treatment plan <strong>in</strong>cluded oral<br />

itraconazole at 5.3 mg/kg every 24 hours, lime<br />

sulfur dips every five days, and discont<strong>in</strong>uation of<br />

Atopica. The food elim<strong>in</strong>ation dietary trial would<br />

be cont<strong>in</strong>ued for 10-12 weeks with Interceptor<br />

be<strong>in</strong>g replaced by Revolution to elim<strong>in</strong>ate<br />

flavored medication. The importance of<br />

conf<strong>in</strong>ement and environmental treatment<br />

to destroy <strong>in</strong>fective spores were emphasized.<br />

Blood work would be performed monthly<br />

with Dr. Doherty to screen for itraconazoleassociated<br />

hepatotoxicity.<br />

At re-exam<strong>in</strong>ation four weeks later, the sk<strong>in</strong><br />

lesions had improved with treatment, however<br />

pruritus was more generalized. Additional<br />

sk<strong>in</strong> lesions <strong>in</strong>cluded the presence of multiple<br />

papules and pustules on the ventral abdomen.<br />

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Sk<strong>in</strong> cytology (impression smear) revealed<br />

moderate neutrophils (often degenerate) with<br />

<strong>in</strong>tracellular and extracellular cocci bacteria,<br />

consistent with superficial pyoderma.<br />

A fungal culture was repeated (negative) and<br />

oral Simplicef at 7.8 mg/kg every 24 hours was<br />

prescribed. Douxo Calm shampoo was also<br />

recommended 1-2 times weekly (prior to lime<br />

sulfur dip) to alleviate pruritus. The itraconazole<br />

was cont<strong>in</strong>ued with a one-week-on, oneweek-off<br />

regime, as this drug accumulates<br />

and ma<strong>in</strong>ta<strong>in</strong>s adequate concentrations <strong>in</strong><br />

kerat<strong>in</strong>ized tissue to allow for pulse dos<strong>in</strong>g.<br />

Upon re-exam<strong>in</strong>ation four weeks later, the sk<strong>in</strong><br />

lesions were resolv<strong>in</strong>g, however pruritus was<br />

escalat<strong>in</strong>g. There was still evidence of superficial<br />

pyoderma on sk<strong>in</strong> cytology. Because both<br />

bacterial <strong>in</strong>fection and resolv<strong>in</strong>g dermatophytosis<br />

were present and may contribute to pruritus, it<br />

was difficult to determ<strong>in</strong>e if improvement was<br />

evident on the dietary trial. However, because<br />

atopy is far more common that adverse reaction<br />

to food, an <strong>in</strong>tradermal sk<strong>in</strong> test (IDST), an<br />

aerobic culture to evaluate for drug resistant<br />

pyoderma, and a fungal culture were performed.<br />

The IDST revealed strong positive reactions to<br />

a 9 month old, male castrated<br />

Labrador Retriever, presented to<br />

“Cody,”<br />

<strong>VCA</strong> VREC with a three month<br />

history of <strong>in</strong>termittent bilateral forelimb lameness.<br />

The lameness improved with rest but worsened<br />

with any activity. He was otherwise normal.<br />

Orthopedic evaluation revealed shift<strong>in</strong>g forelimb<br />

lameness. Both forelimbs had slight abduction<br />

at the elbow, with palpable jo<strong>in</strong>t effusion. Both<br />

elbows were pa<strong>in</strong>ful on extension, and they were<br />

particularly pa<strong>in</strong>ful with palpation of the medial<br />

compartment of the elbow jo<strong>in</strong>t. Other general<br />

and orthopedic f<strong>in</strong>d<strong>in</strong>gs were unremarkable.<br />

house dust mites, storage mites, and cockroaches,<br />

as well as several grasses, weeds, and trees. Aerobic<br />

culture revealed methicill<strong>in</strong> resistant Staphylococcus<br />

pseud<strong>in</strong>termedius sensitive only to amikac<strong>in</strong> and<br />

rifamp<strong>in</strong>. ASIT was re-<strong>in</strong>itiated based on the<br />

comb<strong>in</strong>ed results of both sk<strong>in</strong> and blood allergy<br />

tests. Intensive topical treatments were <strong>in</strong>stituted<br />

<strong>in</strong>clud<strong>in</strong>g daily bath<strong>in</strong>g <strong>in</strong> a Douxo Chlorhexid<strong>in</strong>e<br />

PS shampoo followed by the application of 2%<br />

mupiroc<strong>in</strong> o<strong>in</strong>tment.<br />

Sophie’s sk<strong>in</strong> <strong>in</strong>fections resolved and she was<br />

ma<strong>in</strong>ta<strong>in</strong>ed on a low dose of Temaril-P to<br />

relieve pruritus associated with allergic sk<strong>in</strong><br />

disease and cont<strong>in</strong>ued receiv<strong>in</strong>g allergen specific<br />

immunotherapy and weekly shampoo therapy.<br />

A structured food challenge was performed and<br />

no exacerbation <strong>in</strong> pruritus was appreciated, so<br />

food allergy was considered unlikely.<br />

The complexity and outcome of this case<br />

demonstrates several important considerations<br />

when manag<strong>in</strong>g patients with dermatologic<br />

disease. While dermatophytosis is relatively<br />

uncommon <strong>in</strong> adult dogs, and it is difficult to<br />

determ<strong>in</strong>e if previous drug therapy (prednisone<br />

and cyclospor<strong>in</strong>e) predisposed this patient<br />

to <strong>in</strong>fection, it is important to <strong>in</strong>clude as a<br />

Elbow Dysplasia <strong>in</strong> the Dog<br />

Matthew Palmisano, DVM, Diplomate ACVS<br />

<strong>VCA</strong> Veter<strong>in</strong>ary Referral & Emergency Center<br />

Elbow dysplasia is a term that encompasses four<br />

disease processes: FMCP, ununited anconeal<br />

process (UAP), osteochondritis dissecans (OCD)<br />

of the medial aspect of the humeral condyle,<br />

and asynchronous radius-ulna growth. While<br />

considered separate, these diseases often occur<br />

together and may be <strong>in</strong>terrelated. For example,<br />

both FMCP and UAP are thought to be caused<br />

by asynchronous growth between the radius and<br />

ulna. Also, a percentage of dogs with FMCP<br />

have OCD on the oppos<strong>in</strong>g articular surface<br />

(kiss<strong>in</strong>g lesions). In this region of the country,<br />

FMCP is the most common disease condition<br />

associated with the elbow <strong>in</strong> the young, grow<strong>in</strong>g<br />

large-breed dog.<br />

differential for folliculitis, especially when<br />

sk<strong>in</strong> scrap<strong>in</strong>gs are negative and the response<br />

to antibiotic treatment is poor. Environmental<br />

treatment and oral antifungal therapy are both<br />

important for effective management.<br />

An aerobic culture is <strong>in</strong>dicated when active<br />

cytology persists after an appropriate dose and<br />

duration of antibiotic therapy. Multi-drug<br />

resistant pyoderma is on the rise <strong>in</strong> veter<strong>in</strong>ary<br />

medic<strong>in</strong>e and antibiotic therapy must be prescribed<br />

judiciously. In many cases, topical therapy is the<br />

only option, and while often effective, requires a<br />

very dedicated owner. Identify<strong>in</strong>g and manag<strong>in</strong>g<br />

the underly<strong>in</strong>g cause of pyoderma, especially<br />

when recurrent, is essential.<br />

F<strong>in</strong>ally, ASIT is most effective when based on an<br />

IDST, or a comb<strong>in</strong>ation of <strong>in</strong>tradermal sk<strong>in</strong> and<br />

blood allergy test<strong>in</strong>g, and often allows for less<br />

dependence on medications such as glucocorticoids<br />

and cyclospor<strong>in</strong>e, which was evident <strong>in</strong> this case.<br />

To date, Sophie cont<strong>in</strong>ues to do well with<br />

no cl<strong>in</strong>ical signs of sk<strong>in</strong> disease. Her atopic<br />

dermatitis is well controlled and she is reexam<strong>in</strong>ed<br />

every six months to monitor for any<br />

signs of <strong>in</strong>fection or modification of therapy.j<br />

views are not often helpful, and oblique views of the<br />

elbow are also relatively <strong>in</strong>sensitive at identify<strong>in</strong>g<br />

the fragment. Other imag<strong>in</strong>g modalities <strong>in</strong>clude<br />

CT imag<strong>in</strong>g and MRI. Both techniques have<br />

vary<strong>in</strong>g sensitivity and specificity based on the<br />

literature. Direct visualization of the fragment via<br />

arthroscopy can provide a def<strong>in</strong>itive diagnosis.<br />

Treatment options <strong>in</strong>clude medical therapy, open<br />

arthrotomy, and arthroscopy. Medical therapy<br />

<strong>in</strong>cludes exercise restriction, chondroprotection,<br />

and NSAID therapy. Open arthrotomy <strong>in</strong>volves<br />

mak<strong>in</strong>g a 1-2cm <strong>in</strong>cision on the medial aspect<br />

of the elbow jo<strong>in</strong>t and remov<strong>in</strong>g the fragment<br />

under direct visualization. Studies that have<br />

compared the long-term outcome of medical<br />

therapy to arthrotomy did not f<strong>in</strong>d any<br />

significant difference <strong>in</strong> cl<strong>in</strong>ical improvement<br />

between the two treatments. 1,2 Many patients <strong>in</strong><br />

both treatment groups did not improve.<br />

Radiographs of the elbows were taken (see figures<br />

1-3). Radiographic f<strong>in</strong>d<strong>in</strong>gs <strong>in</strong>clude subtrochlear<br />

Diagnosis of FMCP is primarily made based<br />

bone sclerosis <strong>in</strong> the region of the medial coronoid<br />

on signalment, PE, and radiography. Lateral<br />

process <strong>in</strong> both elbow jo<strong>in</strong>ts on the lateral views.<br />

radiographic views of the elbow jo<strong>in</strong>ts are most<br />

Cody’s signalment, physical exam<strong>in</strong>ation, and<br />

helpful for diagnosis of FMCP. Remodel<strong>in</strong>g of the<br />

radiographic f<strong>in</strong>d<strong>in</strong>gs are most consistent with<br />

subchondral bone beneath the FMCP causes the<br />

elbow dysplasia, most specifically, fragmented<br />

M<strong>in</strong>imally <strong>in</strong>vasive surgery has ga<strong>in</strong>ed popularity<br />

subtrochlear sclerosis seen on the lateral views. AP<br />

medial coronoid process (FMCP) disease.<br />

over the past decade. Arthroscopic surgery of<br />

March/April 2011 Cont<strong>in</strong>ued on page 6<br />

5


Elbow Dysplasia <strong>in</strong> the Dog Cont<strong>in</strong>ued from page 5<br />

the elbow jo<strong>in</strong>t is one of the most commonly<br />

performed m<strong>in</strong>imally <strong>in</strong>vasive procedures <strong>in</strong><br />

veter<strong>in</strong>ary orthopedics. Studies compar<strong>in</strong>g<br />

arthroscopic FMCP removal to arthrotomy and<br />

medical therapy found that arthroscopy was<br />

superior to both open surgery and conservative<br />

management for improvement <strong>in</strong> cl<strong>in</strong>ical signs. 1,2<br />

Arthroscopy’s improved success is likely due to<br />

the decreased trauma to the jo<strong>in</strong>t, as well as more<br />

efficient fragment removal and debridement<br />

of the subchondral bone, due the fact that the<br />

operative field is magnified and bloodless. 3<br />

For Cody, we recommended s<strong>in</strong>gle-session<br />

arthroscopic FMCP removal from both elbow<br />

jo<strong>in</strong>ts. The fragment <strong>in</strong> each elbow was identified<br />

at surgery and removed through a small<br />

<strong>in</strong>strument portal. The rema<strong>in</strong><strong>in</strong>g subchondral<br />

bony bed was debrided down to healthy bleed<strong>in</strong>g<br />

bone. The exposed healthy bone surface forms<br />

a fibr<strong>in</strong> clot, which will eventually remodel <strong>in</strong>to<br />

fibrocartilage. Cody recovered uneventfully from<br />

the surgery and anesthesia.<br />

Cody was discharged the follow<strong>in</strong>g day with<br />

<strong>in</strong>structions for short leash walks for six<br />

weeks. Deramaxx, tramadol, and Clavamox<br />

therapy were adm<strong>in</strong>istered for one week postoperatively.<br />

In addition, Dasuqu<strong>in</strong> therapy was<br />

recommended long-term for jo<strong>in</strong>t support. Sk<strong>in</strong><br />

sutures were removed at two weeks, and Cody<br />

was rechecked at six weeks before return<strong>in</strong>g to<br />

normal activity. At that po<strong>in</strong>t, he was essentially<br />

sound, so he was gradually returned to normal<br />

activity over the follow<strong>in</strong>g two weeks. j<br />

Cont<strong>in</strong>uous Renal Replacement Therapy:<br />

Information for Cl<strong>in</strong>icians<br />

Melissa Holahan, DVM, DACVECC; Samuel Durkan, DVM, DACVECC;<br />

Larry Berkwitt, DVM, DACVIM; Danna Torre, DVM, DACVECC<br />

Cont<strong>in</strong>uous Renal Replacement<br />

Therapy (CRRT) is now available at<br />

<strong>VCA</strong> Shorel<strong>in</strong>e Veter<strong>in</strong>ary Referral<br />

& Emergency Center <strong>in</strong> Shelton, CT. The<br />

<strong>in</strong>formation outl<strong>in</strong>ed here will help you<br />

determ<strong>in</strong>e if you have a patient who may be a<br />

candidate for this treatment.<br />

CRRT is a form of hemodialysis used when<br />

gradual tox<strong>in</strong> (especially BUN) or water<br />

removal is <strong>in</strong>dicated <strong>in</strong> critically ill patients.<br />

6<br />

Figures 1-3: Anteriorposterior<br />

(top), right<br />

lateral (lower right),<br />

and left lateral (lower<br />

left) radiographs of the<br />

elbow jo<strong>in</strong>ts. Note the<br />

subtrochlear sclerosis<br />

(asterisks) <strong>in</strong> the<br />

region of the medial<br />

coronoid process, and<br />

hourglass<strong>in</strong>g (arrows)<br />

of the trabecular bone of<br />

the proximal ulna.<br />

References:<br />

1 Bouck GR, Miller CW, Taves CL. A comparison of surgical and medical management of fragmented<br />

medial coronoid process and OCD of the can<strong>in</strong>e elbow. Vet Comp Orthop Traumatol.<br />

1995;8:177-183.<br />

2 Evans RB, Gordon-Evans WJ, Conzemius MG. Comparison of three methods for the management<br />

of fragmented medial coronoid process <strong>in</strong> the dog. A systematic review and meta-analysis. Vet<br />

Comp Orthop Traumatol. 2008;21:106-109.<br />

3 Beale BS, et al. Arthroscopically-assisted surgery of the elbow jo<strong>in</strong>t. In: Small <strong>Animal</strong> Arthroscopy.<br />

Philadelphia, Pa: W.B. Saunders Co.; 2003:51-79.<br />

The <strong>VCA</strong> Shorel<strong>in</strong>e specialty team will<br />

evaluate each patient on an <strong>in</strong>dividual basis<br />

to determ<strong>in</strong>e if this therapy is appropriate.<br />

In addition to CRRT, there are other forms<br />

of dialysis available for companion animals:<br />

• Intermittent hemodialysis is fast and<br />

efficient at clear<strong>in</strong>g small solutes such as<br />

blood urea nitrogen (BUN), potassium,<br />

and certa<strong>in</strong> tox<strong>in</strong>s, like antifreeze.<br />

• Peritoneal dialysis removes tox<strong>in</strong>s from<br />

the body by way of fluid placed <strong>in</strong>to the<br />

abdomen.<br />

When patients are first started on<br />

<strong>in</strong>termittent hemodialysis, they must be<br />

<strong>in</strong>troduced gradually to allow them time to<br />

adapt. Therefore, the first few treatments<br />

tend to be shorter with slower blood flow.<br />

The speed and time of the treatment is<br />

gradually <strong>in</strong>creased each day. Treatments are<br />

typically performed daily for several days <strong>in</strong><br />

Full Circle Forum


a row until the patient has adapted. Once<br />

the patient is adapted to the treatment, the<br />

treatments generally occur three days a week,<br />

until the patient recovers renal function.<br />

The standard treatment time dur<strong>in</strong>g this<br />

ma<strong>in</strong>tenance phase is usually four hours for<br />

cats and five hours for dogs.<br />

When patients are started on CRRT, the<br />

treatment is <strong>in</strong>tended to be essentially<br />

cont<strong>in</strong>uous which requires 24-hour<br />

specialized nurs<strong>in</strong>g care. After these patients<br />

are stable, they will (<strong>in</strong> most cases) be<br />

switched to <strong>in</strong>termittent hemodialysis. <strong>VCA</strong><br />

Shorel<strong>in</strong>e offers CRRT for dogs <strong>in</strong> acute<br />

renal failure who are at least 10 kg (22 lbs).<br />

Which patients may benefit from<br />

dialysis?<br />

• Patients with acute kidney failure<br />

• Patients who have not responded to<br />

standard therapy with<strong>in</strong> 24 hrs. (fluids,<br />

medication, etc.)<br />

• Patients with life-threaten<strong>in</strong>g complications<br />

of kidney failure or its treatment (e.g. high<br />

potassium levels or fluid with<strong>in</strong> the lungs)<br />

• Patients who have <strong>in</strong>gested tox<strong>in</strong>s that can<br />

be removed with dialysis<br />

Dialysis replaces many of the functions of<br />

the kidneys, but it cannot replace them all.<br />

Therefore, dialysis patients <strong>in</strong> the <strong>in</strong>itial<br />

stages of treatment will need to stay <strong>in</strong> the<br />

hospital between treatments for ongo<strong>in</strong>g<br />

medical care. This <strong>in</strong>cludes fluid treatments,<br />

antibiotics, and anti-ulcer medications,<br />

among others. Because patients with<br />

advanced renal disease often suffer nausea<br />

and vomit<strong>in</strong>g, medications are typically<br />

adm<strong>in</strong>istered parenterally. Hospitalization is<br />

also required to allow for the frequent patient<br />

monitor<strong>in</strong>g that is necessary. Monitor<strong>in</strong>g<br />

<strong>in</strong>cludes blood pressure, ur<strong>in</strong>e production,<br />

blood counts, and serum chemistry.<br />

Is home care needed?<br />

Once the patient is stable and can take<br />

medications by mouth or by a feed<strong>in</strong>g tube<br />

(which is frequently needed dur<strong>in</strong>g the<br />

recovery stage), they may be able to go home<br />

between treatments. The patient would<br />

then return on a treatment schedule of three<br />

days per week. The catheter is covered by<br />

a bandage and needs no care at home other<br />

than to keep it clean and dry.<br />

How long is dialysis cont<strong>in</strong>ued?<br />

When dialysis is used for acute renal failure,<br />

it is cont<strong>in</strong>ued until the kidneys recover<br />

function or it becomes clear that the kidneys<br />

are not go<strong>in</strong>g to heal. Most of the time,<br />

any potential kidney repair that is go<strong>in</strong>g to<br />

occur will happen <strong>in</strong> the first four weeks.<br />

Occasionally the kidneys will heal sooner,<br />

and other times they take longer than four<br />

weeks to heal. There is no way to predict<br />

recovery time at the outset of treatment.<br />

In cases of chronic renal failure, the kidneys are<br />

permanently damaged. Dialysis is cont<strong>in</strong>ued<br />

three times a week for the rest of the patient’s<br />

life. In this case, kidney transplant is the only<br />

alternative to chronic dialysis.<br />

Can dialysis prolong life?<br />

An animal with complete loss of kidney<br />

function will not live more than four to five<br />

days without treatment. However, it can take<br />

up to four weeks for the kidneys to recover<br />

from acute <strong>in</strong>juries. Dialysis is <strong>in</strong>tended to<br />

support patients dur<strong>in</strong>g this heal<strong>in</strong>g time.<br />

However, not all pets with acute kidney<br />

failure can recover, even with dialysis. About<br />

50% of patients who have the support of<br />

dialysis will survive. Unfortunately, the<br />

other 50% cannot be saved despite all of<br />

our efforts. Of those who live, 50% recover<br />

completely with no last<strong>in</strong>g effects while the<br />

other 50% may end up with chronic kidney<br />

disease that requires ongo<strong>in</strong>g dietary and<br />

medical management.<br />

Some types of renal disease have a better<br />

chance of recovery than others. Damage<br />

caused by <strong>in</strong>fections and ischemia to the<br />

kidney can be successfully treated 50-80%<br />

of the time, whereas the chance of recovery<br />

from tox<strong>in</strong> <strong>in</strong>duced kidney failure is only<br />

20% with dialysis.<br />

Pets with chronic kidney failure on lifelong<br />

dialysis may live a year longer than they<br />

would have without dialysis.<br />

How will animals feel dur<strong>in</strong>g dialysis?<br />

Most animals tolerate dialysis well. After the<br />

<strong>in</strong>itial dialysis treatment they may seem to<br />

look their worst, but they usually show signs<br />

of feel<strong>in</strong>g better with<strong>in</strong> 24-72 hours. They<br />

often appear much more alert, they show<br />

<strong>in</strong>terest <strong>in</strong> be<strong>in</strong>g petted, and cats will beg<strong>in</strong><br />

groom<strong>in</strong>g themselves. Some patients will<br />

even beg<strong>in</strong> to eat and dr<strong>in</strong>k when often they<br />

could not be coaxed to do so before dialysis.<br />

Dur<strong>in</strong>g the treatment, patients sit <strong>in</strong> a quiet<br />

room on a cushioned table with a blanket. A<br />

technician is always by their side to monitor<br />

their vital signs and respond to potential<br />

complications. <strong>Animal</strong>s don’t seem to<br />

experience the same degree of exhaustion<br />

after dialysis that many people experience.<br />

What are the risks of dialysis?<br />

Any major medical or surgical <strong>in</strong>tervention<br />

carries risks, and this also is true for dialysis.<br />

Some of the risks are due to the procedure<br />

and some are due to the kidney failure itself.<br />

The staff is tra<strong>in</strong>ed to identify potential<br />

problems so immediate treatment or<br />

preventative measures can be <strong>in</strong>itiated.<br />

How much does dialysis cost?<br />

Hemodialysis is an <strong>in</strong>tensive treatment that<br />

requires sophisticated equipment and 24<br />

hour care with specially tra<strong>in</strong>ed staff. Once<br />

the pet has been evaluated and a therapeutic<br />

plan which <strong>in</strong>cludes dialysis is <strong>in</strong> place,<br />

clients will be given an estimate for the first<br />

week of treatment.<br />

Are there alternatives to dialysis?<br />

Almost all patients considered to be<br />

candidates for dialysis have already failed<br />

to respond to medical management, and<br />

the only other alternative is euthanasia. In<br />

some cases, particularly cats with chronic<br />

kidney disease, kidney transplantation may<br />

be available and would usually be preferred<br />

over dialysis. Kidney transplantation is not<br />

suitable for cats that are severely ill, and<br />

sometimes dialysis is necessary for a few<br />

weeks to allow time to arrange a kidney<br />

transplant. If kidney obstruction (typically<br />

from kidney stones or scarr<strong>in</strong>g after kidney<br />

stones) is the cause of the acute kidney<br />

failure, sometimes dialysis can be avoided<br />

by plac<strong>in</strong>g a tube directly <strong>in</strong>to the kidney to<br />

dra<strong>in</strong> the ur<strong>in</strong>e.<br />

How to have your patients evaluated<br />

for dialysis at <strong>VCA</strong> Shorel<strong>in</strong>e:<br />

If you have a patient <strong>in</strong> whom you have<br />

diagnosed kidney failure, and you and the<br />

owner are <strong>in</strong>terested <strong>in</strong> purs<strong>in</strong>g hemodialysis,<br />

please contact a member of the team to<br />

discuss your pet’s case at (203) 929-8600.<br />

Dialysis is offered by referral only and must<br />

be approved by one of our team members.<br />

If your patient needs emergency dialysis<br />

after hours, please <strong>in</strong>struct your client to<br />

br<strong>in</strong>g them directly to <strong>VCA</strong> Shorel<strong>in</strong>e<br />

Veter<strong>in</strong>ary Referral and Emergency Center<br />

for evaluation as our emergency department<br />

is open 24 hours a day. If emergency dialysis<br />

is <strong>in</strong>dicated based on the emergency doctor’s<br />

evaluation, a member of the dialysis team<br />

will be contacted. j<br />

March/April 2011 7


Veter<strong>in</strong>arians today have many choices<br />

regard<strong>in</strong>g cl<strong>in</strong>ical laboratory test<strong>in</strong>g<br />

for their patients. The choice to use<br />

a reference lab or perform tests <strong>in</strong>-house is<br />

often based on a number of factors <strong>in</strong>clud<strong>in</strong>g<br />

turn-around time, cost, equipment availability,<br />

practicality and feasibility. Basic tests can often<br />

be performed <strong>in</strong> the cl<strong>in</strong>ic, and until recently,<br />

<strong>in</strong>cluded only the most simple and cost-effective<br />

tests. However, with the recent expanded<br />

availability of <strong>in</strong>-cl<strong>in</strong>ic analyzers and rapid test<br />

kits, many cl<strong>in</strong>ics are now perform<strong>in</strong>g a wide<br />

array of diagnostic laboratory tests <strong>in</strong>-house.<br />

Clearly, perform<strong>in</strong>g tests <strong>in</strong> the cl<strong>in</strong>ic has<br />

advantages. Results are available very<br />

quickly and from fresh samples. However,<br />

most cl<strong>in</strong>ics fail to ma<strong>in</strong>ta<strong>in</strong> adequate quality<br />

control and quality assurance programs<br />

which seriously affects the <strong>in</strong>tegrity of<br />

results. In addition, equipment and supplies<br />

are costly to purchase and ma<strong>in</strong>ta<strong>in</strong> often<br />

mak<strong>in</strong>g us<strong>in</strong>g a commercial laboratory the<br />

less expensive option.<br />

Large reference laboratories not only<br />

provide an expansive test menu, but use the<br />

most current technology, well-established<br />

reference ranges, rigorous quality assurance<br />

and quality control, employ highly tra<strong>in</strong>ed,<br />

credentialed personnel and offer consultation<br />

services. However, there are also <strong>in</strong>herent<br />

disadvantages to send<strong>in</strong>g samples to an<br />

outside laboratory. Turn-around time, while<br />

usually with<strong>in</strong> 24 hours for rout<strong>in</strong>e assays,<br />

exceeds <strong>in</strong>-house test<strong>in</strong>g times which may<br />

delay diagnosis and treatment. Samples must<br />

also be stored and transported for periods of<br />

time which may affect their <strong>in</strong>tegrity.<br />

Whether a hospital chooses to run samples<br />

<strong>in</strong>-house or send out, the most important<br />

considerations are the same. Sample acquisition,<br />

sample handl<strong>in</strong>g and sample storage must be<br />

flawless to guarantee sample quality and for<br />

produc<strong>in</strong>g the most accurate results. When<br />

obta<strong>in</strong><strong>in</strong>g samples, whether it is blood, ur<strong>in</strong>e or<br />

tissue, it often helps to remember that the ideal<br />

sample should reflect the <strong>in</strong> vivo state as closely<br />

as possible. Establish<strong>in</strong>g and ma<strong>in</strong>ta<strong>in</strong><strong>in</strong>g strict<br />

8<br />

Cl<strong>in</strong>ical Laboratory Analysis:<br />

Quality Samples Give Quality Results<br />

Michele A. Papero, MHS, CVT<br />

<strong>VCA</strong> Shorel<strong>in</strong>e Veter<strong>in</strong>ary Referral & Emergency Center<br />

protocols for acquir<strong>in</strong>g, handl<strong>in</strong>g, preserv<strong>in</strong>g and<br />

stor<strong>in</strong>g samples is critical as compromise <strong>in</strong> any<br />

of these areas can seriously affect the <strong>in</strong>tegrity<br />

of results and ultimately, jeopardize patient care.<br />

Tra<strong>in</strong><strong>in</strong>g of Personnel<br />

It is imperative that all personnel asked to acquire<br />

or analyze diagnostic samples be appropriately<br />

tra<strong>in</strong>ed. Technicians should understand the<br />

difference between sample types, which tubes<br />

are used for obta<strong>in</strong><strong>in</strong>g each sample type, how to<br />

store samples, how to properly label samples, and<br />

how to complete all paperwork and requisition<br />

forms. Understand<strong>in</strong>g the biology of a laboratory<br />

test, even on a basic level, as well as the disease<br />

state of the patient, will help technicians make<br />

the correct choice when obta<strong>in</strong><strong>in</strong>g samples,<br />

as well as identify results that do not seem<br />

accurate. It is the responsibility of veter<strong>in</strong>arians<br />

and senior staff to be sure that anyone asked to<br />

obta<strong>in</strong> or process laboratory samples is tra<strong>in</strong>ed<br />

appropriately. Tra<strong>in</strong><strong>in</strong>g should also <strong>in</strong>clude how<br />

to f<strong>in</strong>d <strong>in</strong>formation so that sample process<strong>in</strong>g<br />

and analysis is not delayed, and how to ma<strong>in</strong>ta<strong>in</strong><br />

and troubleshoot <strong>in</strong>-house analyzers. Many<br />

test kits and reagents have specific storage and<br />

handl<strong>in</strong>g requirements. Staff responsible for<br />

runn<strong>in</strong>g these assays should read and understand<br />

all materials and <strong>in</strong>structions associated with the<br />

assays and reagents as improper use and storage<br />

will lead to compromised results.<br />

Also important is understand<strong>in</strong>g how to the<br />

handle <strong>in</strong>fectious and zoonotic samples. Every<br />

cl<strong>in</strong>ic should establish protocols for obta<strong>in</strong><strong>in</strong>g,<br />

stor<strong>in</strong>g and dispos<strong>in</strong>g of potentially <strong>in</strong>fectious<br />

samples <strong>in</strong> a way to prevent nosocomial transfer<br />

between patients, and to protect employees.<br />

Wound cultures suspected of conta<strong>in</strong><strong>in</strong>g MRSA<br />

or other zoonotic bacteria, and ur<strong>in</strong>e samples<br />

suspicious for leptospirosis are just two examples<br />

of samples which may be <strong>in</strong>fectious and when<br />

improperly handled can lead to contam<strong>in</strong>ation<br />

or illness. Other examples <strong>in</strong>clude blood and<br />

cultures from patients suspected of hav<strong>in</strong>g<br />

Mycobacterium, nasal swabs or tracheal wash<br />

samples from patients suspected of hav<strong>in</strong>g<br />

fungal <strong>in</strong>fections, and scrap<strong>in</strong>gs from animals<br />

with sk<strong>in</strong> lesions that may conta<strong>in</strong> mites, or<br />

r<strong>in</strong>gworm. The Centers for Disease Control<br />

website (www.cdc.gov) has <strong>in</strong>formation sheets<br />

on many zoonoses, which detail precautionary<br />

measures that should be used when work<strong>in</strong>g<br />

with samples <strong>in</strong> the cl<strong>in</strong>ic and laboratory. These<br />

guidel<strong>in</strong>es should be posted and followed by<br />

any hospital staff member handl<strong>in</strong>g laboratory<br />

samples for <strong>in</strong>-house or send-out analysis.<br />

Packag<strong>in</strong>g diagnostic samples for transport to<br />

remote reference laboratories via courier service<br />

Full Circle Forum


such as FedEx or UPS and air transport should<br />

be done to preserve the sample for the duration<br />

of transport, and must be <strong>in</strong> accordance with<br />

federal regulations. All cl<strong>in</strong>ical samples to<br />

be transported by air courier service require<br />

that special packag<strong>in</strong>g and label<strong>in</strong>g be used to<br />

comply with IATA (International Air Transport<br />

Association) regulations. Both Federal Express<br />

and United Parcel Service have extensive<br />

<strong>in</strong>formation detail<strong>in</strong>g the requirements for<br />

transport of diagnostic cl<strong>in</strong>ical specimens on<br />

their websites. Packages that are sent via FedEx<br />

or UPS must be able to withstand jostl<strong>in</strong>g,<br />

temperature extremes, and delays at transfer<br />

stations or on delivery vehicles. Samples<br />

should be packed so that the environmental<br />

requirements recommended for the test to be<br />

run are ma<strong>in</strong>ta<strong>in</strong>ed. In some cases, special ice<br />

packs and outer packag<strong>in</strong>g may be required to<br />

ma<strong>in</strong>ta<strong>in</strong> the temperature <strong>in</strong>side the package.<br />

Blood and other liquid samples should be <strong>in</strong><br />

conta<strong>in</strong>ers that are secure and leak-proof, as tops<br />

that are not secure can result <strong>in</strong> sample loss via<br />

leakage and evaporation. Cl<strong>in</strong>ics can also receive<br />

large monetary f<strong>in</strong>es if packages show evidence<br />

of leak<strong>in</strong>g contents, or are not packed or labeled<br />

correctly. It is the responsibility of the person<br />

actually plac<strong>in</strong>g the sample <strong>in</strong>side the box to<br />

be sure that all shipp<strong>in</strong>g regulations are met as<br />

well as all of the requirements to ensure the safe<br />

arrival of that sample at the laboratory.<br />

Improperly labeled or packaged samples<br />

sent us<strong>in</strong>g UPS or FedEx will be returned to<br />

the shipper. In these cases, by the time the<br />

time samples are returned, several days have<br />

passed and the sample is no longer cold or<br />

frozen and may have been exposed to extreme<br />

temperature variations render<strong>in</strong>g it useless<br />

and delay<strong>in</strong>g important diagnostic results.<br />

Assur<strong>in</strong>g that all personnel are tra<strong>in</strong>ed is the<br />

best way to avoid this debacle.<br />

Preparation for sampl<strong>in</strong>g<br />

Personnel responsible for obta<strong>in</strong><strong>in</strong>g samples<br />

for laboratory analysis must ensure that all<br />

sample requirements are met <strong>in</strong>clud<strong>in</strong>g patient<br />

preparation, tim<strong>in</strong>g of sample acquisition<br />

(e.g. fast<strong>in</strong>g, or tim<strong>in</strong>g after adm<strong>in</strong>istration of<br />

medication), and special handl<strong>in</strong>g (e.g. freez<strong>in</strong>g,<br />

centrifugation). One of the most common<br />

errors is from submitt<strong>in</strong>g the wrong sample type.<br />

An example of this would be submitt<strong>in</strong>g serum<br />

for a test that requires plasma. Submitt<strong>in</strong>g one<br />

type when another is required will render results<br />

useless. Many drug assays have special sample<br />

requirements, for example they may require<br />

that blood or ur<strong>in</strong>e samples are taken dur<strong>in</strong>g<br />

a small w<strong>in</strong>dow of time before the next dose of<br />

medication or after the last dose of medication<br />

has been adm<strong>in</strong>istered, or samples may require a<br />

special tube. Serum for digox<strong>in</strong> levels, for example,<br />

should not be drawn <strong>in</strong>to serum separator tubes<br />

as the gel can <strong>in</strong>terfere with recovery of the drug.<br />

Taur<strong>in</strong>e levels require plasma, not serum, and<br />

must be kept cold at all times.<br />

Periodic staff tra<strong>in</strong><strong>in</strong>g sessions can be helpful<br />

to make sure that everyone is follow<strong>in</strong>g<br />

the same protocols, and to review any new<br />

<strong>in</strong>formation when it becomes available. There<br />

are also times when a lab or assay kit adopts<br />

new <strong>in</strong>structions; these should be reviewed<br />

with staff and updated <strong>in</strong> a reference notebook<br />

so that everyone is us<strong>in</strong>g the same set of<br />

<strong>in</strong>structions. Most reference laboratories and<br />

equipment manufacturers offer lunch and<br />

learn sessions that can help keep the cl<strong>in</strong>ic<br />

abreast of these changes and review hospital<br />

laboratory protocols with staff.<br />

While there are a variety of sample types<br />

obta<strong>in</strong>ed <strong>in</strong> most cl<strong>in</strong>ics, blood and ur<strong>in</strong>e are<br />

the most common. The follow<strong>in</strong>g sections<br />

make recommendations for acquir<strong>in</strong>g good<br />

quality samples for analysis.<br />

Blood samples<br />

Blood is, by far, the most common sample used<br />

for diagnostic test<strong>in</strong>g. Blood collection and<br />

analysis provide a m<strong>in</strong>imally-<strong>in</strong>vasive means to<br />

assess many physiological parameters. Relative<br />

numbers of red blood cells, white blood cells,<br />

and platelets are determ<strong>in</strong>ed on the complete<br />

blood count us<strong>in</strong>g anticoagulated whole<br />

blood and these results are very important <strong>in</strong><br />

determ<strong>in</strong><strong>in</strong>g a patient’s well-be<strong>in</strong>g. As well,<br />

serum analysis provides <strong>in</strong>formation on lipids,<br />

enzymes, hormones, and antibodies. Whole<br />

blood and serum sample <strong>in</strong>tegrity is dependent<br />

on many th<strong>in</strong>gs, and a poorly acquired or<br />

handled sample has great potential to yield<br />

skewed results on many tests. Below is a list<br />

of considerations to ensure highest quality<br />

samples are obta<strong>in</strong>ed for analysis.<br />

1. Order of draw—To avoid cross<br />

contam<strong>in</strong>ation of tube additives, collection<br />

tubes should always be drawn <strong>in</strong> specific<br />

order. For example, a serum sample will<br />

show a very high potassium level when<br />

there is contam<strong>in</strong>ation of the sample<br />

with the anticoagulant potassium EDTA<br />

conta<strong>in</strong>ed <strong>in</strong> the purple top tube, which<br />

can be transferred via the needle to the<br />

serum separator tube. To avoid these<br />

issues, tubes should be drawn <strong>in</strong> the<br />

follow<strong>in</strong>g order: Serum separator (gel<br />

separator) or red top (no additive), blue<br />

top (sodium citrate for coagulation assays),<br />

green top (hepar<strong>in</strong>), purple top (EDTA).<br />

All sample tubes should be gently <strong>in</strong>verted<br />

several times to mix the blood sample<br />

with the anticoagulants or clot activators.<br />

Never shake samples vigorously.<br />

2. Phlebotomy—Personnel should be<br />

experienced and proficient <strong>in</strong> draw<strong>in</strong>g<br />

blood. Most common lab tests require<br />

venous blood however on occasion<br />

arterial blood samples may be required<br />

for tests such as blood gas analysis.<br />

Special procedures and handl<strong>in</strong>g are<br />

required for arterial blood analysis.<br />

Arterial blood sampl<strong>in</strong>g requires<br />

additional skill and careful attention<br />

to avoid hemorrhage and hematoma<br />

formation. Special collection syr<strong>in</strong>ges<br />

and tubes are necessary so that blood<br />

gases to be analyzed are not volatilized<br />

prior to analysis. Arterial samples should<br />

be analyzed immediately or stored cold <strong>in</strong><br />

an anaerobic environment to avoid errors<br />

<strong>in</strong> blood gas analysis.<br />

When obta<strong>in</strong><strong>in</strong>g venous blood samples,<br />

superficial ve<strong>in</strong>s which are easily palpated<br />

should be used. The animal should be kept<br />

<strong>in</strong> a position where it can rema<strong>in</strong> calm and<br />

comfortable. Excessive paw “pump<strong>in</strong>g”<br />

should be avoided as it can lead to hemolysis<br />

which can alter serum chemistry results and is<br />

undesirable for most tests. Avoid “prob<strong>in</strong>g” the<br />

ve<strong>in</strong> repeatedly as this can lead to hematoma<br />

formation, and as a result, samples obta<strong>in</strong>ed<br />

may conta<strong>in</strong> unwanted clots. Prolonged<br />

tourniquet application causes <strong>in</strong>creased<br />

pressure <strong>in</strong> the ve<strong>in</strong> which leads to artifactual<br />

changes <strong>in</strong> total prote<strong>in</strong>, lipids, cholesterol, and<br />

AST results. Draw<strong>in</strong>g the plunger of a syr<strong>in</strong>ge<br />

back too quickly when obta<strong>in</strong><strong>in</strong>g blood can<br />

damage cells and also cause hemolysis.<br />

Whenever possible, a 22g or larger needle<br />

should be used for obta<strong>in</strong><strong>in</strong>g blood samples<br />

as smaller gauge needles can lead to blood cell<br />

damage. When transferr<strong>in</strong>g blood from the<br />

syr<strong>in</strong>ge to the tubes, avoid forc<strong>in</strong>g the blood<br />

through the needle. Vacuta<strong>in</strong>er needles and<br />

butterflies allow the vacuum to draw the blood<br />

<strong>in</strong>to the tube. They are designed so that the<br />

proper amount of blood is drawn <strong>in</strong>to the tube<br />

with m<strong>in</strong>imal trauma to the cells. Never draw<br />

blood samples from <strong>in</strong>travenous l<strong>in</strong>es unless you<br />

can withdraw and discard at least three times the<br />

volume of the l<strong>in</strong>e before obta<strong>in</strong><strong>in</strong>g the blood<br />

sample. Constituents of <strong>in</strong>travenous fluids and<br />

medications adm<strong>in</strong>istered through the IV l<strong>in</strong>e<br />

can cause sample dilution and alter test results.<br />

3. Sample quantity—There will always be<br />

times when it is difficult to obta<strong>in</strong> sufficient<br />

March/April 2011<br />

Cont<strong>in</strong>ued on page 10<br />

9


Quality Samples Give Quality Results Cont<strong>in</strong>ued from page 9<br />

10<br />

sample amounts (blood, ur<strong>in</strong>e, etc.) for<br />

test<strong>in</strong>g. Patient status (hydration, anemia),<br />

demeanor, and many other factors can<br />

preclude obta<strong>in</strong><strong>in</strong>g appropriate sample<br />

quantity. However, both overfill<strong>in</strong>g and<br />

underfill<strong>in</strong>g blood tubes can seriously alter<br />

test results. Underfill<strong>in</strong>g tubes conta<strong>in</strong><strong>in</strong>g<br />

anticoagulants can lead to cell distortion,<br />

altered red blood cell <strong>in</strong>dices (MCV,<br />

MCHC), falsely lowered hematocrit (<strong>in</strong> the<br />

case of liquid EDTA) and falsely elevated<br />

prote<strong>in</strong> levels by refractometer. Citrate (blue<br />

top) tubes conta<strong>in</strong><strong>in</strong>g <strong>in</strong>sufficient sample<br />

quantity leads to dilution of coagulation<br />

factors and falsely prolonged clott<strong>in</strong>g times.<br />

At the same time, overfill<strong>in</strong>g tubes will<br />

overwhelm the anticoagulant and lead to<br />

unwanted clott<strong>in</strong>g of samples. All sample<br />

tubes have the capacity <strong>in</strong> milliliters written<br />

on the label. It is a good idea to order several<br />

sizes of each tube type so that smaller tubes<br />

can be used for smaller samples, provid<strong>in</strong>g<br />

the f<strong>in</strong>al sample quantity is sufficient for the<br />

tests requested. Outside laboratories, such as<br />

Antech Diagnostics, provide a test manual<br />

which lists the m<strong>in</strong>imum quantity of sample<br />

that can be submitted for each test.<br />

4. Blood sample handl<strong>in</strong>g and storage—<br />

Prior to obta<strong>in</strong><strong>in</strong>g blood samples, any<br />

unique handl<strong>in</strong>g requirements should<br />

be identified. Blood drawn <strong>in</strong>to purple<br />

top EDTA tubes should be refrigerated<br />

immediately and can be submitted for up<br />

to 72 hours if stored properly. Citrated<br />

tubes for coagulation analysis should be<br />

analyzed or refrigerated and submitted<br />

as soon as possible. For serum separator<br />

tubes blood should be allowed to clot,<br />

with the tube upright, for 30 m<strong>in</strong>utes and<br />

then centrifuged immediately. Delay <strong>in</strong><br />

centrifugation will allow the blood cells<br />

to cont<strong>in</strong>ue to metabolize caus<strong>in</strong>g falsely<br />

lowered glucose levels and alteration of<br />

some hormone levels. Separated serum<br />

for chemistry analysis can be stored <strong>in</strong><br />

the refrigerator for 3-4 days. For assays<br />

other than chemistries us<strong>in</strong>g serum, it is<br />

best to check with the laboratory or the<br />

manual for the analyzer if runn<strong>in</strong>g <strong>in</strong>house.<br />

Some tests require that samples<br />

be frozen immediately, however, repeated<br />

freeze-thaw cycles can damage some<br />

constituents. In this case, a common, selfdefrost<strong>in</strong>g<br />

household freezer should not<br />

be used. Occasionally, a test may require<br />

protection from light or some other<br />

special storage or handl<strong>in</strong>g procedure.<br />

These requirements are usually listed <strong>in</strong><br />

the reference laboratory manual.<br />

Ur<strong>in</strong>e samples<br />

Analysis of ur<strong>in</strong>e is valuable <strong>in</strong> diagnos<strong>in</strong>g,<br />

monitor<strong>in</strong>g, and screen<strong>in</strong>g for a number of<br />

conditions and disease states. Some ur<strong>in</strong>e tests<br />

require simply a “clean catch” of ur<strong>in</strong>e, and<br />

others require samples be obta<strong>in</strong>ed sterilely<br />

via catheter or cystocentesis. In either case,<br />

there are many th<strong>in</strong>gs that can affect results.<br />

1. Conta<strong>in</strong>ers—Conta<strong>in</strong>ers used for<br />

collection and transport of ur<strong>in</strong>e specimens<br />

should be rigid, opaque and have a screw<br />

top to m<strong>in</strong>imize leakage and evaporation.<br />

Pet Loss Support Meet<strong>in</strong>gs<br />

First and third Thursdays of every month, Laurie S<strong>in</strong>e,<br />

LMSW, 7 pm—8:30 pm at <strong>Animal</strong> <strong>Specialty</strong> Center, 9 Odell<br />

Plaza, Yonkers, NY. Free of charge, open to the public.<br />

Every Tuesday, Irene Javors, 7:30 pm at Fifth Avenue<br />

Veter<strong>in</strong>ary Specialists, One West 15th Street, New York, NY.<br />

Free of charge, open to the public.<br />

Some cl<strong>in</strong>ics will accept samples <strong>in</strong> recycled<br />

food conta<strong>in</strong>ers or jars, however residual<br />

detergents or food materials can affect the<br />

results by add<strong>in</strong>g glucose or alter<strong>in</strong>g pH.<br />

Us<strong>in</strong>g opaque rather than clear conta<strong>in</strong>ers<br />

will protect the sample from direct<br />

light which can lead to photochemical<br />

breakdown of cl<strong>in</strong>ically important<br />

components such as bilirub<strong>in</strong>. When<br />

possible, it is best to use commercially<br />

available ur<strong>in</strong>e collection conta<strong>in</strong>ers. These<br />

can be disposed of, or cleaned, r<strong>in</strong>sed well,<br />

dried and re-sterilized <strong>in</strong> ethylene oxide<br />

gas. Patient <strong>in</strong>formation should never be<br />

written on the lid of the conta<strong>in</strong>er; always<br />

label the conta<strong>in</strong>er itself as lids can be lost<br />

when the conta<strong>in</strong>er is opened.<br />

For samples which have been obta<strong>in</strong>ed by<br />

cystocentesis <strong>in</strong>to a syr<strong>in</strong>ge, never send the<br />

syr<strong>in</strong>ge and/or needle when submitt<strong>in</strong>g.<br />

The ur<strong>in</strong>e should be transferred, us<strong>in</strong>g<br />

sterile technique, <strong>in</strong>to a sterile red top tube<br />

with no additives.<br />

2. Sample handl<strong>in</strong>g and storage—Ideally,<br />

ur<strong>in</strong>e should be analyzed with<strong>in</strong> two hours<br />

of collection, however, when send<strong>in</strong>g to a<br />

reference lab this is usually not feasible.<br />

Therefore, to ma<strong>in</strong>ta<strong>in</strong> sample <strong>in</strong>tegrity,<br />

it is best to refrigerate ur<strong>in</strong>e samples<br />

immediately to prevent proliferation<br />

of bacteria which can alter glucose and<br />

ketone concentrations. In addition, ur<strong>in</strong>e<br />

stored at room temperature loses carbon<br />

dioxide which will elevate the pH lead<strong>in</strong>g<br />

to the formation or dissipation of crystals<br />

over time. Many crystals are actually<br />

soluble <strong>in</strong> alkal<strong>in</strong>e ur<strong>in</strong>e, so those crystals<br />

which could <strong>in</strong>dicate pathology may not<br />

be observed if the sample is not stored<br />

properly. Refrigerated samples can be<br />

kept and analyzed for up to 72 hours<br />

accord<strong>in</strong>g to our consultants at Antech<br />

Diagnostics.<br />

There are some commercially available<br />

Full Circle Forum


preservatives for ur<strong>in</strong>e, although they are not Careful attention should be paid to<br />

Failure to perform this simple procedure can<br />

result <strong>in</strong> seriously erroneous read<strong>in</strong>gs which<br />

could affect diagnosis of disease state and<br />

selection of treatment plans.<br />

Dipsticks allow for analysis of the chemical<br />

components of ur<strong>in</strong>e. Hemoglob<strong>in</strong>, pH,<br />

bilirub<strong>in</strong>, ketones, glucose, prote<strong>in</strong>, and<br />

urobil<strong>in</strong>ogen can all be semi-quantified on<br />

a s<strong>in</strong>gle dipstick. Each small pad on the<br />

stick is impregnated with reagents. Chemical<br />

constituents of ur<strong>in</strong>e are detected via a chemical<br />

reaction and result<strong>in</strong>g color change on the<br />

pad. These reactions are time dependent and<br />

a common lab error is read<strong>in</strong>g these color<br />

changes too soon. Careful attention should<br />

be paid to the recommended <strong>in</strong>cubation times<br />

prior to read<strong>in</strong>g and record<strong>in</strong>g the results of<br />

each test on the strip.<br />

recommended because while they preserve centrifugation speed when process<strong>in</strong>g ur<strong>in</strong>es While blood and ur<strong>in</strong>e are the most common<br />

cellular components, they alter the chemical for <strong>in</strong>-house analysis. Speeds that exceed samples analyzed both <strong>in</strong> the cl<strong>in</strong>ic and reference<br />

components of the sample. Some special 1500-2000 rpm can damage cells and crystals. laboratory, other types of patient samples<br />

ur<strong>in</strong>e tests (e.g., catecholam<strong>in</strong>es) may require<br />

that the ur<strong>in</strong>e sample be quickly frozen for<br />

preservation. Aga<strong>in</strong>, it is important to have<br />

all of the <strong>in</strong>formation prior to obta<strong>in</strong><strong>in</strong>g the<br />

sample so that results are not affected by poor<br />

sample handl<strong>in</strong>g or storage.<br />

<strong>in</strong>clude biopsy tissue, various body fluids, and<br />

Refractometers used for measur<strong>in</strong>g ur<strong>in</strong>e<br />

a variety of sample types used <strong>in</strong> molecular<br />

specific gravity and total plasma/serum prote<strong>in</strong><br />

biological test<strong>in</strong>g like PCR. These samples<br />

should be calibrated weekly by plac<strong>in</strong>g a drop<br />

require very special handl<strong>in</strong>g or process<strong>in</strong>g to<br />

of distilled water on the glass and zero<strong>in</strong>g the<br />

prevent degradation of DNA or damage to<br />

device follow<strong>in</strong>g the manufacturer’s directions.<br />

cells and tissues. Improperly handled or stored<br />

cultures will result <strong>in</strong> overgrowth or the loss of<br />

<strong>VCA</strong> Shorel<strong>in</strong>e and <strong>VCA</strong> VREC are pleased to announce the addition of<br />

bacteria and <strong>in</strong>valid results.<br />

<strong>VCA</strong> SPECIALTY IMAGING SERVICES<br />

It would be impossible to address all of<br />

these issues here especially s<strong>in</strong>ce sample<br />

requirements often depend on the method<br />

Our specialists are now available to travel to your office <strong>in</strong> Southwestern Connecticut. of analysis used which may vary from lab to<br />

Services <strong>in</strong>clude echocardiography, ultrasound imag<strong>in</strong>g, consultation, case review and<br />

discussion of therapeutic recommendations with you about each case.<br />

Echocardiograms<br />

lab. In these cases, contact your reference<br />

laboratory directly to be sure samples are<br />

obta<strong>in</strong>ed, handled, and submitted seamlessly<br />

and to ensure the best opportunity for<br />

Nathaniel Fenollosa, DVM, DACVIM (cardiology)<br />

accurate and timely test results.<br />

Abdom<strong>in</strong>al & Thoracic Ultrasounds<br />

Consultants at Antech Diagnostics are always<br />

Larry Berkwitt, DVM, DACVIM (<strong>in</strong>ternal medic<strong>in</strong>e)<br />

helpful, can answer all of your questions, and<br />

Dianne Kittrell, DVM, DACVIM (<strong>in</strong>ternal medic<strong>in</strong>e)<br />

can be reached at (800) 872-1001. j<br />

Beth Whitney, DVM, DACVIM (<strong>in</strong>ternal medic<strong>in</strong>e)<br />

References Used:<br />

Lisa Keno, DVM, DACVIM (<strong>in</strong>ternal medic<strong>in</strong>e)<br />

Fischbach F. A Manual of Laboratory and<br />

Michelle Cieplucha, DVM (practice limited to <strong>in</strong>ternal medic<strong>in</strong>e)<br />

Diagnostic Tests. 5th ed. Philadelphia:<br />

Us<strong>in</strong>g our GE Vivid i portable ultrasound system, we will be able to perform <strong>in</strong>office<br />

echocardiograms, abdom<strong>in</strong>al, and thoracic ultrasounds.<br />

The Vivid i is a portable cardiovascular ultrasound unit which allows us to obta<strong>in</strong><br />

real-time diagnostic <strong>in</strong>formation. Our new system is expanded not only for high<br />

performance echocardiography, but is optimized for general, high-resolution<br />

imag<strong>in</strong>g of the thoracic and abdom<strong>in</strong>al cavities, and vasculature.<br />

Lipp<strong>in</strong>cott; 1996.<br />

Rodak BF. Diagnostic Hematology.<br />

Philadelphia: WB Saunders Company;<br />

1995.<br />

Willard MD, Tvedten H, Turnwald<br />

G. Small <strong>Animal</strong> Cl<strong>in</strong>ical Diagnosis by<br />

Laboratory Methods. Philadelphia: WB<br />

If you are <strong>in</strong>terested <strong>in</strong> schedul<strong>in</strong>g any of the above specialists to visit your office, or Saunders Company; 1999.<br />

to obta<strong>in</strong> more <strong>in</strong>formation about this service, please contact Dr. Larry Berkwitt or<br />

Michele Papero at (203) 929-8600, or Dr. Sam Durkan or Kay Wyler at (203) 854-9960.<br />

Personal communication with consultants at<br />

Antech Diagnostics.<br />

We very much look forward to work<strong>in</strong>g with you on this new venture!<br />

March/April 2011 11


March 24, 2011 — <strong>Animal</strong> <strong>Specialty</strong> Center CE<br />

Program. Topic: Neurology: Updates on Seizures,<br />

Jason Berg, DVM, DACVIM (Neurology/Internal<br />

Medic<strong>in</strong>e). Location: 9 Odell Plaza, Yonkers, NY<br />

10701, 6:30 p.m. d<strong>in</strong>ner, 7:30 p.m. lecture, RSVP:<br />

(914) 457-4023 or rcc@animalspecialtycenter.com.<br />

March 29–30, 2011 — Please jo<strong>in</strong> <strong>VCA</strong> Shorel<strong>in</strong>e,<br />

<strong>VCA</strong> VREC, <strong>Animal</strong> <strong>Specialty</strong> Center, <strong>VCA</strong> Boston<br />

Road <strong>Animal</strong> Hospital and <strong>VCA</strong> Cheshire <strong>Animal</strong><br />

Hospital at the upcom<strong>in</strong>g Connecticut Veter<strong>in</strong>ary<br />

Medical Association Annual Meet<strong>in</strong>g which has been<br />

rescheduled for Tuesday, March 29 and Wednesday,<br />

March 30 at the Mystic Marriott <strong>in</strong> Groton, CT. <strong>VCA</strong><br />

Specialists will be available for complimentary case<br />

consultation and radiography review. Br<strong>in</strong>g any<br />

case materials and radiographs you would like to<br />

discuss. For more <strong>in</strong>formation about the meet<strong>in</strong>g<br />

and how to register go to www.ctvet.org or email:<br />

<strong>in</strong>fo@ctvet.org.<br />

Full Circle Forum<br />

One West 15th Street<br />

New York, NY 10011<br />

(212) 924-3311<br />

(212) 924-7228 (fax)<br />

Upcom<strong>in</strong>g Events<br />

April 28, 2011 — <strong>Animal</strong> <strong>Specialty</strong> Center CE<br />

Program. Topic: Radiation Oncology: Update<br />

on CyberKnife, Sarah Charney, DVM, DACVIM<br />

(Oncology), DACVR (Radiology). Location: 9 Odell<br />

Plaza, Yonkers, NY 10701, 6:30 p.m. d<strong>in</strong>ner, 7:30<br />

p.m. lecture, RSVP: (914) 457-4023 or rcc@<br />

animalspecialtycenter.com.<br />

May 17, 2011 — Fifth Avenue Veter<strong>in</strong>ary Specialists will<br />

host an even<strong>in</strong>g of CE at 7:00 p.m. at the Union Square<br />

Ballroom <strong>in</strong> NYC. Our featured speakers will be Dr. Kate<br />

Margalit, DACVS, and Dr. Jessica Chavk<strong>in</strong>, DACVIM.<br />

Please contact Monica Dunn at (212) 924-3311 or<br />

monica.dunn@vcahospitals.com with any questions.<br />

May 26, 2011 — <strong>Animal</strong> <strong>Specialty</strong> Center CE<br />

Program. Topic: Surgery: Fluoroscopic assisted<br />

m<strong>in</strong>imally <strong>in</strong>vasive fracture repair with Dennis T<strong>in</strong>g,<br />

DVM, DACVS. Location: 9 Odell Plaza, Yonkers, NY<br />

10701, 6:30 p.m. d<strong>in</strong>ner, 7:30 p.m. lecture, RSVP:<br />

(914) 457-4023 or rcc@animalspecialtycenter.com.<br />

ANNOUNCEMENTS<br />

Dr. Matthew<br />

Palmisano, staff<br />

surgeon at <strong>VCA</strong><br />

Veter<strong>in</strong>ary Referral<br />

and Emergency Center<br />

<strong>in</strong> Norwalk, CT has<br />

been named Associate<br />

Editor for Small <strong>Animal</strong> Orthopedics <strong>in</strong><br />

Veter<strong>in</strong>ary Surgery. Veter<strong>in</strong>ary Surgery<br />

is the official publication of both the<br />

American and European College of<br />

Veter<strong>in</strong>ary Surgeons. The magaz<strong>in</strong>e<br />

is one of the foremost publications for<br />

small and large animal surgery, and has a<br />

worldwide distribution.<br />

Fifth Avenue<br />

Veter<strong>in</strong>ary Specialists<br />

is pleased to announce<br />

that Dr. Kate Margalit<br />

is now a Diplomate of<br />

the American College<br />

of Veter<strong>in</strong>ary Surgeons.<br />

We are proud to have her as part of the<br />

FAVS specialty staff and look forward to<br />

a long future of work<strong>in</strong>g with her.<br />

First Class Prsrt.<br />

US Postage<br />

PAID<br />

Canoga Park CA<br />

Permit #451<br />

Adm<strong>in</strong>istrative Services provided<br />

by <strong>VCA</strong> <strong>Animal</strong> <strong>Hospitals</strong>, Inc.

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