The aseptic meningitis syndrome.

The diagnosis and treatment of acute meningitis is a challenge for the primary care physician. Differentiating between bacterial meningitis and aseptic meningitis is not always straightforward. The aseptic meningitis syndrome is usually viral in origin, and enteroviruses account for most cases. The aseptic syndrome also may be caused by unusual bacterial organisms such as Mycobacterium tuberculosis, Leptospira species, Brucella species, Borrelia burgdorferi and others. The classic presentation consists of the acute onset of meningismus, headache, fever, malaise with pleocytosis and normal glucose and slightly elevated protein in the cerebrospinal fluid. Cerebrospinal fluid lactate and serum C-reactive protein measurements may be helpful in differentiating aseptic meningitis from treatable bacterial meningitis. Aseptic meningitis of viral origin usually responds to expectant care. Other causes of aseptic meningitis must be searched for and treated if present.