Meningitis is infection of the membranes that surround the brain and spinal cord (meninges)

The incidence of bacterial meningitis has decreased markedly compared to several decades ago as a result of the widespread use of conjugate vaccines and preventive antimicrobial treatment of pregnant women. In first world countries, the incidence of bacterial meningitis is about 45 cases per 100,000 population.

WHAT ARE THE CAUSES?

Meningitis is most commonly caused by viruses. Viral meningitis is usually mild and most people make an excellent recovery from it. Occasionally meningitis is due to bacterial infection, which is the most serious, life-threatening form of meningitis. Less commonly, fungal infection may cause meningitis.

WHAT ARE THE SYMPTOMS?

Meningitis causes headache, fever, vomiting, sensitivity to light, neck stiffness, joint pains, drowsiness, confusion and seizures. In meningococcal meningitis, there may also be a purplish skin rash or bruising. Onset and progression of symptoms can be rapid, and may in severe cases lead to death within hours.

In babies and young children, look out for fever, vomiting, sensitivity to light, refusing feeds, fretfulness, irritability at being handled, decreased responsiveness, being difficult to wake, a purple-red skin rash or bruising, a high moaning cry, cold hands and feet, pale or blotchy skin, arching of the back and seizures.

If you suspect meningitis in someone, treat it as a medical emergency and seek immediate medical attention.

HOW IS IT DIAGNOSED?

Diagnosis is based on taking a history and performing a physical examination. Blood tests and imaging of the brain may also be done. The key test for confirming the diagnosis is a lumbar puncture, which consists of removing spinal fluid via a needle inserted into the back, and examining the fluid for evidence of infection.

WHAT ARE THE TREATMENT OPTIONS?

Bacterial meningitis is treated with intravenous antibiotics in hospital. Other medications such as antiepileptic medicines may be needed to treat complications. Patients who are severely ill may need to be treated in an intensive care unit.

Viral meningitis generally requires only supportive treatment such as for rehydration, fever, headache and vomiting.

WHAT IS THE PROGNOSIS?

Prognosis of meningitis depends on the cause. Untreated bacterial meningitis has a very high death rate. Even with appropriate treatment, the death rate from bacterial meningitis is about 15-20%, with a higher death rate associated with increasing age. The type of bacteria makes a difference, with pneumococcal and Listeria meningitis associated with higher death rates than meningococcal meningitis. Patients who survive may be left with long term disabilities such as deafness, blindness, seizures, paralysis, impaired mental status and loss of limbs. Viral meningitis, on the other hand, is associated with a very good prognosis and generally leads to a full recovery.

Many strains of bacteria which cause bacterial meningitis are now vaccine preventable, such as Haemophilus influenza type b (Hib), meningococcus serogroups A, B, C, W135 and Y, and pneumococcus.