Recurrent meningitis is usually caused by bacteria, viruses, or noninfectious conditions.
Recurrent viral meningitis is most often due to
Typically when HSV-2 is the cause, patients have ≥ 3 episodes of fever, nuchal rigidity, and CSF lymphocytic pleocytosis; each episode lasts from 2 to 5 days, then resolves spontaneously. Patients can also have other neurologic deficits (eg, altered sensorium, seizures, cranial nerve palsies).
The cause is treated if possible. Mollaret meningitis is treated with acyclovir. Most patients recover fully.
Acute bacterial meningitis may recur if it is acquired via a congenital or acquired defect at the skull base or in the spine and that defect is not corrected. If the cause is an injury, meningitis may not develop until many years later.
If patients have recurrent bacterial meningitis, clinicians should thoroughly check for such defects. High-resolution CT can usually show defects in the skull. Clinicians should check the patient's lower back for a dimple or tuft of hair, which may indicate a defect in the spine (eg, spina bifida).
Rarely, recurrent bacterial meningitis (usually due to Streptococcus pneumoniae or Neisseria meningitidis) results from a deficiency in the complement system. Treatment is the same as that used in patients without complement deficits. Vaccination against S. pneumoniae and N. meningitidis (repeated every 3 yr) may reduce likelihood of infection.