Acute encephalitis from 1967 to 1991.
We studied all the adult patients with acute encephalitis, 322 in all, in the Helsinki area, Finland, during the years 1967--1991. The average incidence was 1.4/100000 adults/year. The proportion of known and suggested etiologies in 5-year periods has risen from 36 (1967--71) to 59% (1987--91). Herpes simplex virus was identified most often (16%), followed by varicella-zoster (5%), mumps (4%), and influenza A viruses (4%). In addition, 20 other agents were identified. The leading cause of encephalitis in patients aged 65 years or more was varicella-zoster virus. Eighteen patients (5.6%) died. It appears that the etiology of encephalitis changes with age and with time. It is important to establish the etiological pattern, as this assists in prompt diagnosis, which is a prerequisite for successful therapy.
Rantalaiho
T
T
Department of Virology, Haartman Institute, University of Helsinki, POB 21, FIN-00014, Helsinki, Finland.
Färkkilä
M
M
Vaheri
A
A
Koskiniemi
M
M
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D004569:Electroencephalography; D004660:Encephalitis / Q000097:blood / Q000453:epidemiology / Q000209:etiology; D020803:Encephalitis, Herpes Simplex / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D020804:Encephalitis, Varicella Zoster / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005387:Finland; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D009107:Mumps / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D014057:Tomography, X-Ray Computed