Bacterial Meningitis

Dr. Sudheer Kher

Case Study 

• A 3 yr old girl was brought to the emergency room by 

her parents because of fever and loss of appetite for the 

past 24 hrs and difficulty in arousing her for the past 2 

hrs. 

• The developmental history had been normal since birth. 

Her childhood immunization were current. 

• She attended a day care center and had a history of 

several episodes of presumed viral infections similar to 

those of other children at the center.

Clinical Features 

• Temperature was 39.5 C 

• Pulse-130/min 

• Respirations-24/min 

• BP-110/60 mm Hg

Physical Examination 

• Physical examination showed a well-developed and well-nourished 

child of normal height and weight who was drowsy. 

• When her neck was passively flexed, her legs also flexed (+ve 

Brudzinski sign, suggesting irritation of meninges). 

• Ophthalmoscopic examination showed no papilledema, indicating 

that there had been no long-term increase in intracranial pressure. 

• The remainder of her physical examination was normal.

Laboratory Findings 

• CSF fluid was cloudy. Gram staining showed many 

polymorphonuclear cells with gram negative diplococci 

suggestive of neisseria meningitidis. 

• White blood cell count – 25,000/µL ( markedly elevated), with 

88% PMN forms and an absolute PMN count of 22,000/µL 

(markedly elevated), 6% lymphocytes, and 6% monocytes. 

• CSF protein was 100 mg/dL (elevated) 

• Glucose was 15 mg/dL (low, termed hypoglycorrhachia) 

• Cultures of blood and CSF grew serogroup B N. 

MENINGITIDIS

What is meningitis 

• Meningitis is a common name for infections (inflammation) 

that take place in the meninges surrounding the brain and 

spinal cord. 

• One of the most serious forms of meningitis is 

Meningococcal meningitis. It is caused by Neisseria 

meningitidis. 

• An infection with meningococcal bacteria causes a serious, 

potentially fatal infection called meningococcal disease. You 

may have heard it referred to as bacterial meningitis. 

Meningococcal disease can also cause a very serious condition 

called sepsis (blood poisoning).

Types of meningitis 

• Aseptic meningitis: caused by viruses (e.g. mumps), SLE, and 

some types of medications. 

• Bacterial meningitis: caused by a bacterial infection. 

Numerous microorganisms may cause bacterial meningitis: 

• Neiseria meningitidis 

• Streptococcus pneumoniae 

• Listeria monocytogenes 

• Haemophilus influenzae (type B) 

• Mycobacterium tuberculosis 

• Group B Streptococci 

• Escherichia coli

Types of meningitis (cont.) 

• Viral meningitis: caused by viruses (enterovirus). 

• Tuberculous meningitis: caused by tuberculosis infection 

due to Mycobacterium tuberculosis. 

• Cryptococcal meningitis: caused by infection from a yeast 

called Cryptococcus (found in soil and bird droppings). Often 

associated with AIDS. 

• Neoplastic meningitis: caused by the spread of solid 

tumors to the brain or spinal cord. 

• Syphilitic meningitis: due to infection with the bacterium 

that causes syphilis

Epidemiology 

• SOURCE & RESERVOIR: 

• Man 

• Subclinical infection 

• carrier (they carry the bacteria in their nose and throat but 

never become sick) 

• MODES OF TRANSMISSION: 

• Close contact with a person who is sick with the disease 

• Contact with carriers 

• Living in close quarters, such as college dormitories 

• Being in crowded situations for prolonged periods of time 

• Sharing drinking glasses, water bottles, or eating utensils 

• Kissing, sharing a cigarette

Epidemiology (cont.) 

• INFECTIOUS MATERIAL: 

• Nasopharyngeal secretions 

• PEOPLE AT RISK: 

• Neonates 

• Children, teens, and young adults 

• Elderly 

• People who have a weakened immune system 

• AIDS patients are at high risk for Tuberculous meningitis

Etiology 

• Bacterial meningitis is due most often to hematogenous spread 

of bacteria to the leptomeninges. 

• It can also be seen after head trauma as skull fracture through 

the sinuses. 

• Local infections such as mastoiditis may also lead to meningitis. 

• Surgery or CNS infection such as cranial epidural abscess may 

lead to meningitis.

Etiology (cont.) 

• Neonates: Group B Streptococci, Escheridia coli, Listeria 

monocytogenes 

• Infants: Neissera meningitidis, Haemophilus influenzae, 

Streptococcus pneumoniae 

• Children: N. meningitidis, S. pneumoniae 

• Adults: S. pneumoniae, N. meningitidis, Mycobacteria, 

Cryptococci

Pathogenesis 

• Bacteria extend through the wall of blood vessels into the 

subarachnoid space followed more slowly by neutrophils as 

the blood brain barrier breaks down. 

• The combination of bacteria and neutrophils in the 

subarachnoid space irritates the underlying cerebral cortex 

causing edema and increased intracranial pressure. 

• If the meningitis is not treated neutrophils are followed by 

lymphocytes and macrophages which with the bacteria, cause 

irritation and degeneration of cranial nerves, production of 

intimal fibrosis in arteries and fibrosis of the leptomeninges 

which can lead to cortical infarcts and blockage of the 

foramina of Lushcka and Magendie with hydrocephalus.

Pathogenesis

General Gross Description 

• The brain in purulent meningitis has an opacity of the 

leptomeninges by neutophils and bacteria. This is seen 

over the convexity and the base. 

• The brain is also usually swollen.

General Microscopic 

Description 

• In acute purulent meningitis, the subarachnoid space is filled 

with neutrophils and bacteria with increasing numbers of 

macrophages and lymphocytes over time. 

• The underlying brain is usually protected by the pia so that 

there is no intracerebral inflammation, however, the cortex 

and white matter will show spongy change or vacuolization 

due to edema. 

• Infants more often show bacteria and neutrophils invading the 

underlying parenchyma.

Symptoms 

• Sudden high fever : 

The infection causes a high fever of about 130F or more which does 

not get lower with a tepid bath or fever reducing medicine 

• Severe, persistent headache 

• Neck stiffness and pain that makes it difficult to touch your chin to 

your chest is due to the swelling around the Meninges 

• Nausea and vomiting, sometimes along with diarrhea 

• Confusion and disorientation (acting "goofy") can progress to stupor, 

coma, and death 

• Drowsiness or sluggishness 

• Eye pain or sensitivity to bright light 

• Muscle or joint pain or weakness

Symptoms 

• Abnormal skin color 

• Reddish or brownish skin rash or purple spots that do not turn 

white when u press on them are a sign of sepsis. These may develop 

because of inflammation and bleeding in small blood vessels 

throughout the body, including those under the skin. 

• Ice-cold hands and feet 

• Numbness and tingling: Sepsis (also called blood poisoning) can 

reduce the amount of blood that gets to the persons hand and feet, 

causing coldness and numbness. 

• Seizures: Swelling of brain tissue, increases pressure inside the skull, 

and hampers blood flow, causing stroke symptoms, paralysis and 

seizures.

Glass Test 

• Press the side of the glass 

tumbler against the rash 

• If the rash does not disappear 

then it is a symptom of 

meningitis.

Symptoms In Children 

• Severe high fever 

• Feeding problems 

• Vomiting 

• Irritability 

• Seizures 

• High-pitched crying 

• Decreased appetite 

• The skin over the fontanelles (soft spots between the 

skull bones) becomes taut, and the fontanelles may bulge. 

• Infants may not develop a stiff neck

Diagnosis 

WHEN TO CALL THE DOCTOR: 

• If a child 2 years old or younger has an unexplained fever and 

the parent senses that the child is ill. 

• If a child becomes increasingly irritable or unusually sleepy, 

refuses to eat, vomits, has seizures, or develops a stiff neck. 

• If an adult has fever, headache, skin rash, confusion, 

unresponsiveness (stupor), seizures, and a stiff neck.

Diagnosis (cont.) 

KERNIG SIGN: 

• The Kernig sign is positive if pain in the lower back or 

posterior thigh occurs when the knee is extended while the 

patient is lying in the supine position and the hip is flexed at a 

right angle.


BRUDZINSKI SIGN: 

• The Brudzinski sign is positive if knee and hip flexion occurs 

when the neck is flexed while the patient is in the supine 

position.


NECK STIFFNESS: 

• Nuchal rigidity is typically assessed with the patient lying 

supine, and both hips and knees flexed. 

INVESTIGATIONS DONE: 

• Blood test 

• Chest X-ray 

• CSF analysis 

• CT scan or MRI (MRI preferred over CT due to its 

superiority in demonstrating areas of cerebral edema, ischemia, 

and meningeal inflammation) 

• Cultures of samples of CSF, blood, urine, mucus from the nose 

and throat, and pus from skin infections.

Diagnosis – CT Scan


CSF ANALYSIS: 

• A spinal tap (lumbar puncture) is performed. A thin needle is 

inserted between L4/L5 to withdraw a sample of CSF. 

• The sample of CSF is sent to a laboratory, where the bacteria 

can be cultured and identified. 

• 3 tubes of CSF are collected 

• One for chemistry analysis for glucose & protein levels and 

cell count 

• One for microbiology analysis for Gram stain, bacterial 

culture… 

• One for cytology analysis 

• It will help doctors distinguish between the different type of 

meningitis.

CONDITION GLUCOSE PROTEIN CELLS 

Bacterial meningitis Low High High 

(>300/mm³) 

Viral meningitis Normal Normal or 

high 

Mononuclear 

(

• Antimicrobial susceptibility testing should be performed on all 

clinically relevant bacteria isolated from CSF, so that the 

antibiotic therapy that was started immediately can be 

adjusted if necessary. 


• Culture media used for bacterial culture of CSF are: 

• 5% sheep blood agar 

• Enriched chocolate agar 

• Enrichment broth (eg, thioglycolate) 

• Culture plates should be incubated in an atmosphere 

containing 5 to 10% CO2.


• METHODS FOR DETECTING BACTERIA IN CSF: 

• Gram staining 

• Acridine orange stain 

• Fluorochrome stain (bacteria appear bright red) 

• More sensitive than gram stain 

• Reduction in the time of examination of CSF smear 

• Requires fluorescence microscope 

• Wayson stain 

• Simple & sensitive stain for screening CSF smears for 

bacteria 

• Bacteria appear dark blue


• Quellung procedure (Quellung capsular reaction) 

• Used to confirm presence of S.pneumoniae, 

N.meningitidis, or H.influenzae 

• Antisera specific for the capsular polysaccharides of each 

of these 3 bacteria are mixed with separate portions of 

clinical specimens. 

• Formation of Ag/Ab complexes on the surfaces of these 

bacteria induces changes in the refractive indices of their 

capsules. 

• The capsules appear clear & swollen.


• METHODS FOR DETECTING BACTERIAL ANTIGENS: 

• CIE (counterimmunoelectrophoresis) 

• COAG (coagglutination) 

• LA (latex agglutination) 

• OTHER METHODS USED: 

• EIA (enzyme immunoassays) 

• LAL Assay (limulus amebocyte lysate assay) 

• GLC (gas-liquid chromatography) 

• PCR (polymerase chain reaction)

Complications 

If the disease is left untreated, the following manifestatations are seen: 

• Increased spinal fluid pressure 

• Myocarditis: inflammation of the heart 

• Hydrocephalus (blockage of spinal fluid in brain) 

• Mental retardation 

• Deafness :Loss of hearing from infiltration of the 8th nerve 

• Brain damage:Spread from the meninges to the brain is called 

meningoencephalitis 

• Severe diarrhea and vomiting 

• Internal bleeding 

• Low blood pressure 

• Shock 

• Death

Complications 

• Waterhouse-Friderichsen syndrome 

• Adrenal gland failure due to bleeding into the adrenal 

gland. 

• Symptoms include acute adrenal gland insufficiency and 

profound shock. It is deadly if not treated immediately

Treatment 

• Because bacterial meningitis is a medical emergency, it's 

important to start the treatment as soon as it is diagnosed or 

even suspected. 

• Bacterial meningitis is treated with antibiotics. The doctor will 

start intravenous (IV) antibiotics with a corticosteroid (eg, 

Dexamethasone) to bring down the inflammation before all 

the test results are even known. When the specific bacteria are 

identified, he may decide to change antibiotics or not. 

• In addition to antibiotics, it is important to replenish fluids lost 

from fever, loss of appetite, sweating, vomiting and diarrhea.

Treatment (cont.) 

• Some patients may need to stay in the hospital, depending on 

the severity of the illness and the treatment needed. 

• Complications can require additional treatment. 

• Anticonvulsants (eg, Diazepam or Phenytoin) might be given 

for seizures. 

• Additional IV fluids in case of shock or low blood pressure. 

• Supplemental oxygen or mechanical ventilation if the child 

has difficulty breathing. 

• All neonates should have a hearing test following their 

recovery to screen for hearing impairment.

Microorganism 

Recommended 

therapy 

Duration of 

treatment 

Streptococcus 

pneumoniae 

Neisseria 

meningitidis 

Penicillin G or Ampicillin 

OR 

Vancomycin + Thirdgeneration 

cephalosporin 

(eg, ceftriaxone or 

cefotaxime) 

Penicillin G 

OR 

Third-generation 

cephalosporin (eg, 

ceftriaxone or cefotaxime) 

2 weeks 

7 days

Haemophilus 

influenzae 




7 days 

Listeria 

monocytogenes 

Ampicillin or Penicillin G 

3 weeks 

Escherichia coli 




21 days or 2 weeks 

Group B 

streptococci 

Ampicillin or Penicillin G 

14-21 days

Prognosis 

• If treated immediately, most patients who have acute bacterial 

meningitis recover fully. 

• But when diagnosis or treatment is delayed, permanent brain 

damage or death becomes more likely, especially in very young 

children and older people. 

• Some patients develop seizures that require lifelong treatment. 

• Even with appropriate treatment, about 5-15% patients die 

from bacterial meningitis. 

• 10-20% of patients who survive bacterial meningitis have brain 

damage, hearing problems, or developmental difficulties 

(especially in children).

Prevention 

• Cases of bacterial meningitis should be reported to state 

or local health authorities so that they can follow and 

treat close contacts of patients and recognize outbreaks. 

• Overseas travelers should check to see if meningococcal 

vaccine is recommended for their destination. Travelers 

should receive the vaccine at least 1 week before 

departure, if possible.

Prevention (cont.)

Prevention (cont.) 

IMMUNIZATION: 

• Haemophilus influenzae type b (Hib) vaccine 

• Part of the recommended immunization schedule in 

children. 

• 3 doses given at 2, 4 and 6 months of age, a booster dose is 

given at 12-15 months of age. 

• Pneumococcal conjugate vaccine (PCV7) 

• Recommended for children under 2-5 years old who are at 

high risk of pneumococcal disease (weak immune system). 

• 4 doses given at 2, 4, 6 and 12-15 months of age.


• Pneumococcal polysaccharide vaccine (PPV) 

• Recommended for adults >65 and children >2 years who 

have long-term health problems. 

• 1 dose is given (under some circumstances a 2nd dose may 

be given). 

• Meningococcal conjugate vaccine (MCV4) 

• Recommended for children from 11 to 18 years who 

haven't yet been vaccinated, who are at high risk of bacterial 

meningitis, for microbiologists, for overseas travelers. 

• 1 dose is given.


CHEMOPROPHYLAXIS: 

• Rifampin is given to family members of an infected person to 

reduce their risk of contracting the disease as H influenzae can 

persist in the nasopharyngeal secretions even after a successful 

treatment. 

• Pregnant women should not take rifampin as it may harm the 

fetus. They should be treated with single doses of ciprofloxacin, 

azithromycin, or ceftriaxone.

Tuberculous meningitis 

DEFINITION: 

• Infection of the meninges caused by Mycobacterium 

tuberculosis (acid-fast Gram-positive mycobacterium), the 

bacteria that causes tuberculosis. 

• It is the most severe form of tuberculosis. 

• It is caused by the spread of Mycobacterium tuberculosis to 

the brain, from another site in the body. Infection begins in the 

lungs and may spread to the meninges by a variety of routes.

Tuberculous meningitis (cont.) 

EPIDEMIOLOGY: 

• In areas with much tuberculosis, 

• tuberculous meningitis usually affects young children 

• it develops after the primaty tuberculosis infection 

• In areas with less tuberculosis, 

• tuberculous meningitis tends to strike adults. 

• it is due to reactivation of an old focus of tuberculosis that 

had been dormant


RISK FACTORS: 

• history of pulmonary tuberculosis 

• excessive alcohol use 

• AIDS 

• other disorders that compromise the immune system


SYMTOMS: (usually begin gradually) 

• Fever 

• Sluggishness 

• Loss of appetite 

• Severe headache 

• Nausea and vomiting 

• Stiff neck 

• Sensitivity to light (Photophobia) 

• Loss of consciousness


DIAGNOSIS: 

• CSF analysis 

• Chest radiography 

• CT scan or MRI 

• Sputum examination 

• Sputum culture 

• Tuberculin skin testing


TREATMENT: 

• If tuberculous meningitis is seriously suspected, treatment 

should start immediately. 

• Start with 2 month intensive course of isoniazid, rifampin, 

pyrazinamide, and ethambutol followed by 4 months of 

isoniazid and rifampin. 

• The use of the corticosteroid (eg, dexamethasone) improves 

survival but probably does not prevent severe disability. 

• The hydrocephalus (accumulation of CSF in the brain) may 

require placement of a ventriculoperitoneal shunt.


COMPLICATIONS: 

• Brain damage which may cause 

• motor paralysis 

• seizures 

• mental impairment 

• abnormal behavior 

• Cerebral ischemia ( anterior circulation most commonly) 

• Mesencephalic infarction 

• Syringomyelia ( disorder in which a cyst or tubular cavity 

forms within spinal cord)

Prognosis of TB meningitis 

• Fatal if untreated 

• It causes severe neurologic deficits or death in >50% 

of cases 

• Long-term follow up is necessary to detect 

recurrences


PREVENTION: 

• BCG vaccine (given at birth) 

• PPD (Purified Protein Derivative) Tuberculin test determines if 

someone has developed an immune response to M. 

tuberculosis 

• 0.1mL injected immediately under the surface of the skin of 

the forearm 

• Test should be read between 48 and 72 hours after the 

injection for induration (hardness) 

• Classified as positive based on the diameter of the 

induration

Bibliography 

• http://www.cdc.gov/ncidod/DBMD/diseaseinfo/meningococcal_g.htm 

• http://www.umm.edu/altmed/articles/meningitis-000106.htm#Following%20Up 

• http://www.wrongdiagnosis.com/b/bacterial_meningitis/intro.htm 

• http://www.immunize.org/searchiac3/searchiac3.asp?zoom_cat=- 

1&zoom_and=1&zoom_per_page=10&zoom_query=bacterial+meningitis 

• http://www.clevelandclinic.org/health/health-info/docs/3300/3384.asp?index=11039 

• http://www.dhpe.org/infect/Bacmeningitis.html 

• http://www.emedicine.com/PED/topic198.htm 

• http://www.nlm.nih.gov/medlineplus/ency/article/000680.htm 

• http://www.kidshealth.org/parent/infections/lung/meningitis.html 

• http://www.meningitisuk.org/about-meningitis/bacterial-meningitis/frequently-askedquestions.htm 

• http://www.meningitisuk.org/about-meningitis/bacterial-meningitis/frequently-askedquestions.htm 

• http://www.guideline.gov/summary/summary.aspx?ss=15&doc_id=5946&nbr=00391 

5&string=bacterial+AND+meningitis

THANK YOU

Bacterial Meningitis

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