Definition of Aseptic meningitis:

Aseptic meningitis is an illness that appears similar to bacterial meningitis. However, bacteria do not grow in cultures of the fluid around the brain and spinal cord (cerebrospinal fluid). This may occur because there are no bacteria, or because the bacteria are difficult to grow.

See also:

• Meningitis
• Meningitis - cryptococcal
• Meningitis - Gram-negative
• Meningitis - H. influenzae
• Meningitis - meningococcal
• Meningitis - pneumococcal
• Meningitis - staphylococcal
• Meningitis - tuberculous

Causes, incidence, and risk factors:

There are many causes of aseptic meningitis, including:

• Cancer (causes a syndrome similar to meningitis)
• Infections near the brain or spinal cord, such as epidural abscesses
• Fungi
• Medications (cause a syndrome similar to meningitis)
• Mycobacteria (nontuberculous)
• Syphilis
• Tick-borne diseases (such as Lyme disease)
• Tuberculosis
• Viruses

About half of aseptic meningitis cases are caused by coxsackie virus or echovirus, two members of the enterovirus family. The rate of enteroviral infections increases in the summer and early fall. Enteroviruses are spread by hand-to-mouth contact and coughing. They also may be spread by contact with fecal matter.

Other viruses that cause this condition include:

• Chickenpox (varicella virus)
• Other enteroviruses
• Herpes simplex viruses, usually type 2
• HIV (especially acute HIV syndrome)
• Mumps
• Rabies virus
• West Nile virus

Risk factors for aseptic meningitis include:

• Being a health care worker
• Having a weakened immune system
• Exposure to children in a day care setting
• Exposure to someone with a recent viral infection