Noninfectious meningitis is inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space between the meninges (subarachnoid space) and is caused by disorders that are not infections or by drugs.

The subarachnoid space is located between the middle layer and the inner layer of the meninges (see Biology of the Nervous System: Viewing the Brain). This space contains the cerebrospinal fluid.

Noninfectious meningitis is a type of aseptic meningitis (meningitis caused by something other than the bacteria that typically cause acute meningitis).

Disorders and drugs are uncommon causes of meningitis. Disorders that most commonly cause meningitis include disorders that cause inflammation, including the inflammation that occurs when the body's immune system malfunctions and attacks the body's own tissues (autoimmune disorders). Such disorders include rheumatoid arthritis and systemic lupus erythematosus (lupus).

Drugs that can cause meningitis include nonsteroidal anti-inflammatory drugs (NSAIDs) and certain antibiotics.

Noninfectious meningitis may also develop after fluid leaks from a brain cyst into the subarachnoid space. Such cysts may be caused by a tapeworm infection called cysticercosis (see Brain Infections: Cysticercosis).

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Some Causes of Noninfectious Meningitis Type Examples Disorders Behçet syndrome Cancer that has spread to the brain from other parts of the body (as can occur in leukemia, lymphoma, melanoma, or breast or lung cancer) Rheumatoid arthritis Rupture of a brain cyst Sarcoidosis Sjögren syndrome Systemic lupus erythematosus (lupus) Drugs that suppress the immune system (used to treat autoimmune disorders and inflammation or to prevent rejection of a transplanted organ) AzathioprineSome Trade Names IMURAN CyclosporineSome Trade Names NEORAL SANDIMMUNE Cytosine arabinoside Immune globulin given by vein (intravenously) Muromonab (OKT3) Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofenSome Trade Names ADVIL MOTRIN , naproxenSome Trade Names ALEVE ANAPROX NAPROSYN , sulindacSome Trade Names CLINORIL , and tolmetinSome Trade Names TOLECTIN Other drugs Certain antibiotics, such as ciprofloxacinSome Trade Names CILOXAN CIPRO , isoniazid, and penicillin CarbamazepineSome Trade Names TEGRETOL (an anticonvulsant) PhenazopyridineSome Trade Names PYRIDIUM PLUS (used to treat urinary symptoms) RanitidineSome Trade Names ZANTAC (used to treat stomach ulcers) Sulfa drugs, such as trimethoprim-sulfamethoxazoleSome Trade Names (an antibiotic) and sulfasalazineSome Trade Names AZULFIDINE (used to treat ulcerative colitis) Substances that are injected into the subarachnoid space* for treatment or diagnosis Anesthetics Antibiotics Chemotherapy drugs Radiopaque dyes used in imaging tests Vaccines Pertussis (whooping cough) Rabies Smallpox *The subarachnoid space contains cerebrospinal fluid and is located between middle and inner layers of tissue that cover the brain and spinal cord (meninges).

Symptoms

Usually, noninfectious meningitis causes symptoms that are similar to those of bacterial meningitis but are milder and may develop more slowly. Symptoms include headache, a stiff neck, and often fever. When the neck becomes stiff, lowering the chin to chest becomes painful.

Most people recover in 1 to 2 weeks.

Diagnosis

Doctors suspect meningitis when people have a headache and stiff neck, particularly with fever. They then try to determine whether meningitis is bacterial (requiring immediate treatment) or not. If the symptoms are less severe, the cause is less likely to be bacteria.

A spinal tap (lumbar puncture—see Symptoms and Diagnosis of Brain, Spinal Cord, and Nerve Disorders: Spinal Tap) is done to obtain a sample of cerebrospinal fluid, which is sent to a laboratory to be examined and analyzed. Sugar and protein levels and the number and type of white blood cells in the fluid are determined. The fluid is cultured to check for bacteria and thus rule out or confirm bacterial meningitis. Noninfectious meningitis is possible when the fluid contains excess white blood cells (indicating inflammation) and does not contain any bacteria that could be the cause. Then other tests are done to identify infectious organisms other than bacteria, such as viruses and fungi. Noninfectious meningitis is likely If a noninfectious cause (such as a disorder that is not an infection, a drug, or recent vaccination) is possible and the person's symptoms and test results do not suggest that the cause is an infection.

If doctors suspect that a brain cyst is the cause, they do magnetic resonance imaging (MRI) of the brain or, if MRI is unavailable, computed tomography (CT).

Treatment

If people appear very ill, doctors start treatment right away without waiting for test results to identify the cause. Treatment includes antibiotics, which are given until doctors are sure that these people do not have bacterial meningitis, which, if untreated, can quickly cause permanent brain damage or death (see Meningitis: Acute Bacterial Meningitis). They are also given acyclovirSome Trade Names
ZOVIRAX
(an antiviral drug) in case the infection is due to herpes simplex virus.

After the cause is identified, doctors treat the cause accordingly—for example, by treating a disorder or stopping a drug. Symptoms are treated as needed.

Last full review/revision February 2013 by John E. Greenlee, MD