Thrombocytopenia, leukopenia and abnormal liver function tests in the initial phase of tick-borne encephalitis.

One-hundred-seventy-five patients in whom bone marrow puncture had been performed at the Department of Infectious Diseases, University Medical Centre, Ljubljana, during the period from 1988 to 1992, were analysed in a retrospective study. In five out of these 175 patients, tick-borne encephalitis virus infection was confirmed by serological tests and in all of them bone marrow puncture was performed in the initial phase of the illness as part of diagnostic work-up in a patient with a febrile illness accompanied by leukopenia and thrombocytopenia. Bone marrow examination revealed minimal reactive changes or normal findings. In addition to leukopenia and thrombocytopenia, abnormal liver function tests were also found in four patients. All these patients later developed meningoencephalitis, i.e. they had clinically typical tick-borne encephalitis with biphasic course of the illness. In the initial phase of tick-borne encephalitis in addition to well-known leukopenia, thrombocytopenia and abnormal liver function tests may be found.