[Listeriosis of the central nervous system]

Listeriosis of the CNS is an inflammatory disease of the central nervous system that occurs mostly sporadically or occasionally as a limited epidemic. The pathogens are generally ingested with the food. Whether or not the infection becomes manifest in an exposed person depends on the number of pathogens ingested, on the virulence of the Listeria strain and on the individual disposition. It appears to be of decisive importance for an infection that the cellular immunodefense mediated by the T cells is disturbed; however, even persons without any previous disease worth mentioning may be affected. The characteristics of the various CNS manifestations are demonstrated via the case histories of 12 own patients (acute meningitis and meningoencephalitis, brain stem encephalitis, brain abscess, meningoencephalitis with infected cerebral infarct, chronic recidivating encephalitis). Early neurological focal signs and symptoms, combined with CSF findings atypical for bacterial CNS disease, should not be taken lightly and may point to listeriosis even though they are not specific for CNS listeriosis. The decisive criterion is the proof of the pathogen in the blood or CSF or the proof of antibody titre changes in the serum. Recent CSF diagnostic methods such as CSF lactate determination and the identification of IgG-positive B lymphocytes are useful in differentiating between viral and noninflammatory CNS disease; most important for follow-up are repeat CSF examinations. High-dosage ampicillin or amoxycillin treatment combined with gentamycin is the therapy of choice in CNS listeriosis. The bactericidal effect achieved thereby is desirable especially if immunodefense is disturbed. Prognosis of CNS listeriosis depends on the underlying disease in each case. The high mortality even among persons who had been healthy before the infection, is at least in part due to delayed diagnosis.