Meningitis is occasionally caused by noninfectious conditions (eg, noninfectious disorders, drugs, vaccines). Many cases of noninfectious meningitis are subacute or chronic Subacute and Chronic Meningitis Subacute meningitis develops over days to a few weeks. Chronic meningitis lasts ≥ 4 weeks. Possible causes include fungi, Mycobacterium tuberculosis, rickettsiae, spirochetes, Toxoplasma... read more 
.
(See also Overview of Meningitis Overview of Meningitis Meningitis is inflammation of the meninges and subarachnoid space. It may result from infections, other disorders, or reactions to drugs. Severity and acuity vary. Findings typically include... read more .)
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 Acute Bacterial Meningitis Acute bacterial meningitis is rapidly progressive bacterial infection of the meninges and subarachnoid space. Findings typically include headache, fever, and nuchal rigidity. Diagnosis is by... read more .
Diagnosis of noninfectious meningitis is based on analysis of cerebrospinal fluid (CSF) obtained by lumbar puncture Lumbar puncture Acute bacterial meningitis is rapidly progressive bacterial infection of the meninges and subarachnoid space. Findings typically include headache, fever, and nuchal rigidity. Diagnosis is by... read more (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).
