Acute encephalitis. A survey of epidemiological, clinical and microbiological features covering a twelve-year period.
The 191 adult patients with acute encephalitis who attended the Department of Neurology, University Hospital, Helsinki, during the 12-year period 1967-78, were analyzed for epidemiological, clinical, and microbiological features. Young healthy adults of either sex under 30 years of age were the most susceptible. The duration of symptoms varied from some hours to more than one month (less than or equal to 5 days in half of the patients). Prodromal symptoms were observed in 37.7%, meningeal signs or symptoms in 93.2%, features indicating brain involvement in 84.3% and clear effects on consciousness in 27.7% of the patients. Half (50.8%) recovered, while 43 (22.5%) were left with at least moderate disability after the acute phase. Twelve patients (6.3%) died. Lower socioeconomic status and age over 35 years were associated with increased mortality. The 10 patients with proven or presumptive herpes simplex virus (HSV) etiology had a mortality of 40% and only one recovered satisfactorily. There were 14 further cases suggestive of HSV. Mumps, Coxsackie B, adeno, and measles were the most frequent identifiable causes after HSV. Other etiological factors, including bacteria, appeared occasionally. The etiology remained obscure in 58.6% of the cases.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001419:Bacteria / Q000302:isolation & purification; D004660:Encephalitis / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D005260:Female; D005387:Finland; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012737:Sex Factors; D018139:Simplexvirus / Q000302:isolation & purification; D014780:Viruses / Q000302:isolation & purification