The brain and spinal cord are covered by 3 thin membranes, the dura mater, the pia mater and the arachnoid. These membranes are called the “meninges”. Meningitis is an inflammation of these membranes and the cause is almost always an infection due to a viral agent or a bacterial agent.
Viral meningitis is more common than the bacterial type. Viral meningitis is usually less severe and more benign. Meningitis caused by a bacterial agent can be very serious and can lead death if not treated promptly and properly. The outbreaks of meningitis in young persons in school or college which often make headlines is usually of the bacterial type and hence the concern because it can be a very serious illness.
The symptoms of both viral and bacterial meningitis are similar. Usually headache is the predominant symptom, but fever is also usually present and the neck is stiff. Bending the neck forward greatly aggravates the pain. The headache is generalized all over the head. Drowsiness and confusion may be present in the more severe cases. Seizures are rare in meningitis, but common in encephalitis which is an infection of the brain tissue. The onset of the headache and fever usually occurs quite rapidly. Often there is a history of an upper respiratory infection or sore throat prior to the onset of the severe headache and fever. A sinus infection or lung infection (pneumonia) may be present which can allow bacteria to get into the blood stream and spread throughout the body and infect the meninges.
A spinal tap with analysis of the spinal fluid is crucial in making the diagnosis. Staining for bacteria and analyzing the amount and types of white cells present will help differentiate between a viral and a bacterial meningitis.
It is important to start antibiotics immediately if evidence suggests that the cause is bacterial. Viral meningitis is treated by controlling the fever, the use of analgesics for the headache and IV fluids.