Meningitis is occasionally caused by noninfectious conditions (eg, noninfectious disorders, drugs, vaccines). Many cases of noninfectious meningitis are subacute or chronic.
(See also Overview of Meningitis.)
Symptoms of noninfectious meningitis are similar to those caused by other kinds of meningitis (eg, headache, fever, nuchal rigidity). Severity and acuity can vary, but noninfectious meningitis tends to be less severe than acute bacterial meningitis.
Diagnosis of noninfectious meningitis is based on analysis of cerebrospinal fluid (CSF) obtained by lumbar puncture (preceded by neuroimaging if increased intracranial pressure or an intracranial mass effect is suspected). CSF findings may include
Lymphocytic or neutrophilic pleocytosis
Elevated protein
Usually normal glucose
Noninfectious meningitis can be suspected if microbiologic testing does not detect any evidence of pathogens, particularly in patients with disorders known to cause meningitis (eg, Behçet syndrome, Sjögren syndrome). However, in these patients, infectious meningitis may be caused by atypical or hard-to-culture organisms. Noninfectious meningitis can also be suspected if episodes of meningitis are temporally associated with exposure to a potentially causative drug.
Treatment of noninfectious meningitis involves treating causative disorders and stopping causative drugs. Otherwise, treatment is supportive.
If patients appear seriously ill, appropriate antibiotics and corticosteroids are started immediately (without waiting for tests results) and continued until acute bacterial meningitis is ruled out (ie, CSF is shown to be sterile).
