Adult Encephalitis Associated with Rubella Virus Infection: Analysis of 12 Adult Cases Reported in Japan

Many cases of encephalitis associated with rubella virus infection were reported (44 cases between 1935 to 1976, 222 cases between 1976 to 1981) in Japan, and 11 adult cases were involved in these cases. In view of the rarity of this association, a case of 22 years old man, who was affected by encephalitis associated with rubella virus infection, was reported, and we discussed clinical and laboratory findings of 11 adult cases. In addition, comparative analysis of clinical and laboratory findings between adult cases and infant cases was done. Case report: 22 years old man, his family history and past history was not remarkable. Chief Complaint: Vomiting and loss of consciousness. Present Illness: There was an onset of exanthema on his trunk, headache and fever. These symptoms diminished 3 days later. Chief complaint manifested 7 days later from the onset and he was admitted. Level of his consciousness was 100, and he did not exhibit pathological reflex nor meningeal irritation syndrome. Examination of the blood disclosed leukocytosis with a shift to the left in the hemogram. HI titer of rubella was positive in dilution of 1: 516 in sera, CRP was false positive and IgA showed an increase. Urinalysis showed a 1+ test for albumin and 2+ for glucose. The sediment contained 18 to 20 white cells and many red cells per high-power field. A lumbar puncture revealed an inital pressure equivalent to 75mm of water, and the fluid gave 189/3 cells (granulocyte 59/3, lymphocyte 130/3). The EEG showed slowing θ wave. HI titer of rubella on 7 days later from onset was positive in dilution of 1: 8162 in sera. Comparative analysis of clinical and labolatory findings between adult cases and infant ones was as follows: Infant cases were liable to exhibit nausea, vomiting and convulsion on onset, and had poor prognosis with higher mortality, but adult cases did not exhibit such syndromes on onset and had better prognosis.