[Microbiologic-immunologic laboratory diagnosis in suspected meningitis/encephalitis].

The diagnosis on the exclusion of infectious diseases of the central nervous system, especially of bacterial infections still is one of the most important issues in clinical microbiology. In bacterial meningitis, where lethal courses as well as severe sequelae are still frequent, there should be a rapid diagnosis not only with microscopy but also with Limulus test and antigen detection tests because a specific therapy should be initiated as soon as possible. But also viral infections caused by varicella or herpes virus are increasingly susceptible to chemotherapy. The indication for the examination of cerebrospinal fluid, the minimal volume for exhaustive laboratory tests and the possibilities of a stepwise diagnostic procedure are given with reference data from literature for the various techniques. In our experience the synopsis of laboratory results and clinical symptoms yielded in 75% of all cases the exclusion of an infectious etiology of the disease. In 17% a bacterial meningitis or the infection of a hydrocephalus shunt could be diagnosed. Viral infections could be proven in 4% either by antibody or by antigen detection. Only in 1% of all patients the clinical symptoms and the laboratory parameters remained unclear.