Meningitis: Types and pathologies

Q. What are the differences between viral and bacterial meningitis?

A. Meningitis is an infection that causes inflammation of the meninges, the membranes that protect the brain and spinal cord. Meningitis is most commonly caused by viruses (viral) and bacteria (bacterial), though there are other, less common forms.

About 4,000 cases of bacterial meningitis occur in the United States each year, with about 500 deaths. Viral meningitis is more common and can be quite uncomfortable for the patient but resolves without treatment.

There are important differences between viral and bacterial meningitis. Initial symptoms may be the same and usually consist of high fever, stiff neck, and headaches. Other symptoms may include nausea, vomiting, increased sensitivity to light, and sudden change in moods or confusion.

Viral meningitis is the most common type, occurring mostly in the late summer and early fall. It is caused by non-polio enteroviruses; however, only a small number of people infected with the enterovirus will actually develop meningitis. It can be transmitted to others through close contact. In viral meningitis, the majority of patients are completely awake and alert and mainly complain of severe headache with fever. Most people with viral meningitis get better within seven to 10 days.

There are two main types of bacterial meningitis: pneumococcal and meningococcal. If caught early, both are treatable with antibiotics. Meningococcal meningitis is often found on college campuses, schools, and among other groups of people because the bacteria are spread through close contact. This type is more common in younger people.

Pneumococcal is caused by the same bacteria that causes pneumonia. It can occur in any age group. Patients who have had their spleen surgically removed, and sickle cell patients, are especially vulnerable. Without prompt treatment, both bacterial strains are lethal and can cause considerable damage. Unlike viral meningitis, bacterial meningitis often presents with confusion, coma, seizures, and shock.

The most effective way to protect you and your family or loved ones against both types of bacterial meningitis is to complete the recommended vaccine schedule. There are effective vaccines against meningitis caused by pneumococcus, meningococcus, and hemophilus (a form of childhood meningitis which has largely been eradicated by vaccination).

There are other treatable causes of severe headache and fever and these symptoms should prompt a call to your physician or an emergency department visit for evaluation.

- Ronald Goren, M.D., is an infectious
disease specialist
at Nazareth
Hospital