Wednesday, June 12, 2024
HomeNeurologyMeningococcal Meningitis

Meningococcal Meningitis

Practice Essentials

Most patients with meningococcal meningitis, caused by the gram-negative diplococcus Neisseria meningitidis, recover completely if appropriate antibiotic therapy is instituted promptly. Nonetheless, the disease still is associated with a high mortality rate and persistent neurologic defects, particularly among infants and young children.

The image below shows indications of increased intracranial pressure, an early complication of bacterial meningitis.

Head CT demonstrates enlargement of the temporal h

Head CT demonstrates enlargement of the temporal horns indicating increased intracranial pressure (horizontal open large arrow). The closed arrowhead shows small intracerebral hemorrhage foci on the right temporal lobe, and the curved arrow shows the effect of increased intracranial pressure on the cerebellum.

View Media Gallery

Signs and symptoms

Meningococcal meningitis is characterized by acute onset of the following:

Intense headache

Fever

Nausea

Vomiting

Photophobia

Stiff neck

Lethargy or drowsiness in patients frequently is reported. Stupor or coma is less common. If coma is present, the prognosis is poor.

Patients also may complain of skin rash, which usually points to disease progression. Elderly patients are prone to have an altered mental state and a prolonged course with fever.

Meningococcal septicemia, which is characterized by rapid circulatory collapse and a hemorrhagic rash, is a more severe, but less common, form of meningococcal disease.

Young children

In young children, meningococcal meningitis can manifest as follows:

Subacute infection that progresses over several days

Irritability

Projectile vomiting

Seizures, usually with a focal onset – Typically during the first few days

Waterhouse-Friderichsen syndrome – Characterized by large petechial hemorrhages in the skin and mucous membranes, fever, septic shock, and disseminated intravascular coagulation (DIC)

Insidious onset – Can be a feature in infants; stiff neck may be absent

In children, even when the combination of convulsive status epilepticus and fever exists, the classic signs and symptoms of acute bacterial meningitis may not be present.

See Clinical Presentation for more detail.

Diagnosis

Laboratory studies

Laboratory examination of the cerebrospinal fluid (CSF) usually confirms the presence of meningitis. Typical CSF abnormalities in meningitis include the following:

Increased opening pressure (>180 mm water)

Pleocytosis of polymorphonuclear leukocytes (white blood cell [WBC] counts between 10 and 10,000 cells/µL, predominantly neutrophils)

Decreased glucose concentration (< 45 mg/dL)

Increased protein concentration (>45 mg/dL)

Other laboratory tests can include the following:

Culture of CSF and blood specimens – To identify N meningitidis and the serogroup of meningococci, as well as to determine the bacterium’s susceptibility to antibiotics

Polymerase chain reaction (PCR) assay – For confirmation of the diagnosis

Imaging studies

Computed tomography (CT) scanning – Indications for performing CT scanning prior to lumbar puncture include an altered level of consciousness, papilledema, focal neurologic deficits, and/or focal or generalized seizure activity

Magnetic resonance imaging (MRI) – MRI with contrast is preferred to CT scanning, because MRI better demonstrates meningeal lesions, cerebral edema, and cerebral ischemia

Electroencephalography

An electroencephalogram (EEG) study is sometimes useful to document irritable electrical patterns that may predispose the patient to seizures.

See Workup for more detail.

Management

To prevent serious neurologic morbidity and death, prompt institution of antibiotic therapy is essential when the diagnosis of bacterial meningitis is suspected. Antimicrobial treatment should be administered as soon as possible after a lumbar puncture is performed.

Empiric pharmacologic therapy

Initial empiric therapy until the etiology of the meningitis is established should include the following agents:

Dexamethasone

A third-generation cephalosporin – Eg, ceftriaxone or cefotaxime

Vancomycin

Acyclovir – Should be considered according to the results of the initial CSF evaluation

Doxycycline – Should also be added during tick season in endemic areas

Postdiagnosis pharmacologic therapy

Ceftriaxone (or cefotaxime) – The drug of choice for the treatment of meningococcal meningitis and septicemia

Penicillin – Alternative

Ampicillin – Alternative

Dexamethasone – Controversial in the management of bacterial meningitis in adults

Prophylaxis

Deterrence and prevention of meningococcal meningitis can be achieved by either immunoprophylaxis or chemoprophylaxis. Rifampin, quinolones, and ceftriaxone are the antimicrobials that are used to eradicate meningococci from the nasopharynx.

Currently, vaccinations against meningococcus A, C, W, and Y are available. The first meningococcal vaccine for serogroup B was approved in October 2014.

See Treatment and Medication for more detail.

RELATED ARTICLES
- Advertisment -

Most Popular