Recurrent meningitis is meningitis that occurs more than once.
Occasionally, people have two or more episodes of meningitis. Recurrent meningitis may be caused by bacteria, viruses, or other conditions.
Most often, bacterial meningitis recurs when an unrepaired injury or birth defect allows bacteria to enter the space between the layers of tissue (meninges) that cover the brain and spinal cord. The defect may be in the base of the skull, allowing bacteria from the sinuses, middle ear, or bone behind the ear (mastoid process) to enter. Or the defect may be in the meninges or spinal cord (called a neural tube defect), usually in the neck or lower back. The only symptom may be a dimple or a tuft of hair on the skin over the spine. Meningitis due to an injury or a birth defect may take months or years to develop.
Rarely, recurrent bacterial meningitis results from a hereditary (congenital) disorder that affects part of the immune system called the complement system. In such cases, the bacteria most likely to be the cause are Streptococcus pneumoniae (usually) or Neisseria meningitidis (less often).
If bacterial meningitis recurs, doctors do a physical examination and sometimes take x-rays or do CT to check for defects in the skull base and spinal column. They may also do blood tests to check for hereditary disorders of the immune system.
Recurrent bacterial meningitis is treated with antibiotics and dexamethasone (a corticosteroid—see Treatment).
Viral meningitis due to herpes simplex virus type 2 may recur. This type of recurrent meningitis is called Mollaret meningitis. Typically, people have three or more episodes of fever, headache, and a stiff neck. The episodes usually last 2 to 5 days, then resolve on their own. People may appear drowsy or sluggish. Some have seizures, vision problems, or hearing loss. Mollaret meningitis is treated with the antiviral drug acyclovir. Most people recover fully.
Recurrent meningitis may also be caused by conditions that are not infections (see Table 1: Some Causes of Noninfectious Meningitis). If one episode of meningitis was caused by a drug, meningitis may recur if people take the drug again.
Meningitis caused by leakage of a brain cyst may also recur. These cysts are diagnosed by magnetic resonance imaging (MRI) of the brain and/or spinal cord or, if MRI is unavailable, computed tomography (CT).
Last full review/revision February 2013 by John E. Greenlee, MD