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Meningitis

Meningitis is an inflammation of the membranes (meninges) surrounding the brain and spinal cord, usually due to infection. Bacterial meningitis is potentially life threatening infection of the nervous system.

Meningococcal meningitis is bacterial meningitis, which can cause severe brain damage and is fatal in 50% of cases if untreated.

Causes
- Meningitis is caused by viral, bacterial and fungal infections. Non-infective causes of meningitis include drugs, immune disorders like lupus and cancer.
- Viruses - Enteroviruses are a common cause of meningitis.
- Bacteria - Streptococcus pneumoniae (pneumococcus), neisseria meningitidis (meningococcus), haemophilus influenzae (haemophilus) listeria monocytogenes (listeria).
- Fungi - Cryptococcus neoformans

Symptoms
The most common symptoms are a, high fever, headaches and vomiting. There may be associated sensitivity to light, confusion, seizures, focal neurological deficits and neck stiffness. It is important to remember that any fever with headache and vomiting could be due to meningitis.

The presentation may be atypical with low grade fever, lethargy, drowsiness in elderly, newborns, immunocompromised (HIV patients) and alcoholics.

Transmission
The bacteria are transmitted from person to person through droplets of respiratory or throat secretions. Close and prolonged contact like sneezing or coughing on someone, or sharing eating or drinking with an infected person facilitates the spread of the disease.

Diagnosis
Meningitis is confirmed by cerebrospinal fluid analysis done by lumbar puncture. Bacteria can be seen by microscopic examination or grown on culture media. Bacterial antigens can be detected in CSF by agglutination and polymerase chain reaction (PCR).

Treatment
Bacterial meningitis is a neurologic emergency. Once meningitis is suspected admission to hospital and institution of prompt antibiotic therapy is must.

  Microorganism Standard Therapy Alternative Therapy
  H Influenzae Third Gen Cephalosporin Chloramphenicol, Penicillin/ Ampicillin (resistance common)
  N Meningitidis Penicillin,  Ampicillin Third Gen Cephalosporin, Chloramphenicol
  S pneumoniae Penicillin,  Ampicillin (resistance common) Third Gen Cephalosporin, Vancomycin, Meropenem, Chloramphenicol
  Listeria Monocytogenes Ampicillin, Penicillin Meropenem, Septran

Complications
Even when diagnosed early and after adequate treatment mortality is 5% to 10% within 24 to 48 hours after the onset of symptoms. Cerebritis, brain abscess, septic venous thrombophlebitis, hemorrhagic infarction, ↑ intracranial pressure, hydrocephalus, subdural effusion, focal deficits (hemiparesis, cranial neuropathy), seizures, cognitive decline are the other complication of bacterial meningitis.