Creutzfeldt-Jakob disease in Sweden.

OBJECTIVES To find and investigate, retrospectively, as many cases as possible of Creutzfeldt-Jakob disease (CJD) in Sweden dying during the period 1 January 1985 to 31 December 1996 and to detect any possible case(s) of new variant CJD. METHODS The patients were found through computer search of all death certificates in Sweden on which CJD was mentioned, through information from the Swedish neuropathologists, and spontaneous reports from Swedish doctors and hospitals. Data concerning the patients were then collected from patients' case records and from brain histopathology reports. RESULTS In total 72 cases of spongiform encephalopathy were confirmed as definite by neuropathology, one of them with Gerstmann-Stäussler-Scheinker disease. In 51 further cases there were no brain pathology data but the diagnosis "probable" (37 patients) or "possible" (14 patients) CJD according to WHO criteria could be made on clinical grounds. There was a variation in number of deaths/year, from a minimum of five (1985) to a maximum of 16 (1990). Sixty patients died during the period 1985-90 and 62 during 1991-6. The sex ratio was nearly 1:1. Calculated for a population of 8.6 million (mean of 12 years) in Sweden this gives 1.18/million/year. Age at the time of the presenting symptoms ranged from 34 to 84 years. Only one patient was under 40 at the onset of symptoms. He had a spongiform encephalopathy but prion protein staining was negative. The duration of symptoms that could be attributed to CJD was 6 months or less in 75 cases, 7-12 months in 16 cases, 1 to 2 years in 15 cases, and more than 2 years in 16 patients. By definition all patients were demented. Other more common symptoms and signs were aphasia, dysphasia, dysathria, ataxia, myoclonus, pareses of the extremities, rigidity or spasticity, different types of hyperkinesias, and other psychiatric symptoms (depression, anxiety, and aggressiveness). Less common symptoms were hallucinations (mainly visual), visual defects, sensory symptoms (paraesthesias, itching, or pain), apraxia of swallowing, and disorders of eye movements. CONCLUSIONS The incidence, the symptomatology, the age distribution (age in years at onset and at death), and the duration of illness were similar to those of other countries except for the cases of new variant CJD in the United Kingdom. There is so far no indication of any cases of new variant CJD in Sweden.