Acute Flaccid Paralysis Accompanying West Nile Meningitis Ahmed ...
Acute Flaccid Paralysis Accompanying West Nile Meningitis Ahmed ...
Acute Flaccid Paralysis Accompanying West Nile Meningitis Ahmed ...
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Adjusting the Therapeutic Threshold: An Evolving Target in Carotid Stenosis Severity?<br />
Staples, AM, DO; Basil, S, OMS3; Heisecke, J, MD; Makdisi, T, MD, FACP<br />
Berkshire Medical Center, Department of Internal Medicine, Pittsfield, MA<br />
Introduction: Carotid stenosis, previously deemed worrisome as it reached severe criteria, is<br />
now increasingly a concern in those with mild to moderate stenosis. Recent studies have shown<br />
that the majority of patients with transient ischemic attacks and minor strokes have a nonsevere<br />
degree of stenosis with ulceration of the carotid atherosclerotic plaques. Ulceration adds<br />
a degree of instability and necessitates further attention.<br />
Case: A 62 year old male with past medical history of atrial fibrillation on Coumadin with<br />
therapeutic INR, hypertension and hyperlipidemia presented to the ER for several recent<br />
episodes of slurred speech, drooling, right-sided facial asymmetry, and confusion, each lasting<br />
5-10 minutes. Patient denied any sensory loss or similar episodes in past. His medications<br />
included Coumadin, Atenolol and Crestor. Physical exam was benign except for an irregularly<br />
irregular heart rhythm. There were no derangements in laboratory data. EKG showed rate<br />
controlled atrial fibrillation. Echocardiogram revealed a LVEF of 50% without mural thrombus.<br />
MRI of the brain showed 3 areas of acute infarction in the territory of the left middle cerebral<br />
artery. MRA of the carotids revealed a 50% left carotid stenosis with an ulcerated plaque. Given<br />
the unilateral pattern and known atrial fibrillation on therapeutic anticoagulation, the ulcerated<br />
carotid plaque was deemed the etiology of his cerebrovascular accident. Left carotid<br />
endarterectomy was performed with Hemashield carotid patch angioplasty, and intraoperative<br />
evidence of ulceration extending through the wall of the internal carotid artery and into the<br />
adjacent soft tissue. The patient was discharged without residual focal neurological deficit.<br />
Discussion: Severe carotid artery stenosis has long been known to be a cause of TIAs and<br />
stroke. However, in the recent past, several cases of TIAs and strokes have been reported in<br />
people with mild to moderate degree stenosis. Further research has shown that 90% of patient<br />
with TIA, amaurosis fugax and minor stroke have stenosis < 50%. Two-thirds of such patients<br />
were found to have a plaque ulceration. Presence of ulceration was directly proportional to the<br />
amount of lipid rich necrotic core and plaque volume. Echolucent plaques, i.e., those with higher<br />
levels of lipid and hemorrhage have been linked to an increased risk of CVA.<br />
Ulceration within a stenotic carotid artery is more prevalent in areas of chronic high shear stress<br />
and sudden changes in intra-arterial pressures as these areas are more prone to plaque<br />
erosion, which in turn cause focal inflammatory changes leading to degradation of plaque wall<br />
and subsequent ulceration. A flow dynamics study further explained that a slipstream flow is<br />
disturbed immediately distal to stenotic area, allowing a backward slipstream to enter the ulcer<br />
in diastole, creating a potential for platelet aggregation. Furthermore, at peak systole, a<br />
whirlpool like circulation was noticed, which had the potential to suck those aggregates from the<br />
ulcer, leading to frequent small embolizations.<br />
Diagnosis can be established with the help of a two-dimensional echo, which can detect<br />
stenosis and an MRA, which detects both stenosis and presence of ulceration. Additionally,<br />
convergent color doppler has been shown to be the best non-invasive and feasible diagnostic<br />
modality for diagnosis of ulcerative lesions with atherosclerotic lesions. Treatment involves<br />
carotid endarterectomy to prevent recurrence of TIAs or stroke. During carotid endarterectomy,<br />
plaque area is cut in full length and not mobilized much due to fear of embolization, thus<br />
explaining the reason for lack of connection between ulceration and symptomatic patients until<br />
recently.