Aseptic Meningitis (Sterile Meningitis)

What is Aseptic Meningitis?
Statistics on Aseptic Meningitis
Risk Factors for Aseptic Meningitis
Progression of Aseptic Meningitis
Symptoms of Aseptic Meningitis
How is Aseptic Meningitis Diagnosed?
Prognosis of Aseptic Meningitis
How is Aseptic Meningitis Treated?
Aseptic Meningitis References

What is Aseptic Meningitis?

Aseptic meningitis is an illness characterised by headache, fever, and inflammation of the lining of the brain (meninges). The most common cause is enterovirus. It can also be caused by nonbacterial organisms (e.g. viruses, fungi, spirochetes, parasites), nonpyogenic bacteria, specific agents, or other disease processes. The illness is usually mild and runs its course without treatment; however, some cases can be severe and life threatening.

Statistics on Aseptic Meningitis

2-27 cases per 100,000 population per year; however, this figure is probably higher due to under-reporting. Infections occur any time of the year, with a increase in incidence during summer and autumn in temperate climates.

The majority of cases occur in children and young adults.

Risk Factors for Aseptic Meningitis

Many different things can cause aseptic meningitis, including viruses, fungi, tuberculosis, worms, some medications, and infections near the brain or spinal cord, such as epidural abscesses.

Risk factors for aseptic meningitis include:

Exposure to someone with recent virus infection;
Exposure to children in a daycare setting;
Being a healthcare worker; or
Having a suppressed immune system.

Progression of Aseptic Meningitis

In most cases, people with aseptic meningitis will recover completely over a matter of weeks and not suffer permanent damage as a result. However, tiredness, lightheadedness and muscle aches may persist for a period of time after recovery.

Encephalitis (infection of brain itself) may develop rarely.

Infection may last much longer in a person with a depressed immune system.

Symptoms of Aseptic Meningitis

Symptoms can include:

Neck stiffness;
Headache;
Fever;
General discomfort, uneasiness, or ill feeling (malaise);
Sore throat;
Nausea and vomiting;
Drowsiness;
Abdominal pain;
Chills;
Rash;
Muscle pain;
Confusion;
Abnormal sensitivity to light (photophobia).

How is Aseptic Meningitis Diagnosed?

Tests may reveal the following:

High or low white blood cell count in blood;
Elevated white blood cells in spinal fluid;
Bacterial cultures do not grow any bacteria.

Suspicion of viral meningitis is based on the clinical presentation and presence of certain CSF findings. Since no specific treatment is available for acute viral meningitis in immunocompetent individuals (except meningitis due to herpes) and since the presentation is often nonspecific, exclusion of other conditions becomes highly important. Until CSF findings become available, the differential diagnosis of aseptic meningitis is very broad, encompassing many toxic and vascular diseases.

Prognosis of Aseptic Meningitis

Aseptic meningitis is a benign disease, and people usually have full recovery in 5 to 14 days after the onset of symptoms. Fatigue and lightheadedness may persist longer in some people.

How is Aseptic Meningitis Treated?

Treatment is needed for fungal or mycobacterial causes of aseptic meningitis. Supportive therapy consists of analgesic medications and management of complications of encephalitis, if that occurs. No specific treatment is available for viral aseptic meningitis.

Aseptic Meningitis References

Booss J, Harris SA. Neurology of AIDS virus infection: A clinical classification. Yale J Biol Med. 1987;60(6):537-43. [Abstract | Full text]
Connolly KJ, Hammer SM. The acute aseptic meningitis syndrome. Infect Dis Clin North Am. 1990;4(4):599-622. [Abstract]
Faust S, Nadel S. Meningitis, aseptic [online]. Omaha, NE: eMedicine; 2004 [cited 3 January 2006]. Available from: URL link
Hankey G, Wardlaw J. Clinical Neurology. New York, NY: Demos Medical Publishing; 2002. [Book]
Jolles S, Sewell WA, Leighton C. Drug-induced aseptic meningitis: Diagnosis and management. Drug Saf. 2000;22(3):215-26. [Abstract]
Nelsen S, Sealy DP, Schneider EF. The aseptic meningitis syndrome. Am Fam Physician. 1993;48(5):809-15. [Abstract]
Newton HB. Common neurologic complications of HIV-1 infection and AIDS. Am Fam Physician. 1995;51(2):387-98. [Abstract]
Parasuraman TV, Frenia K, Romero J. Enteroviral meningitis: Cost of illness and considerations for the economic evaluation of potential therapies. Pharmacoeconomics. 2001;19(1):3-12. [Abstract]
Johnson RP. Aseptic meningitis in adults [online]. Waltham, MA: UpToDate; 2005 [cited 3 January 2006]. Available from: URL link