Clinical and epidemiological characteristics of subacute sclerosing panencephalitis in Bulgaria during the past 25 years (1978–2002)

Abstract

The aims of the present study are to establish the subacute sclerosing panencephalitis (SSPE) incidence in Bulgaria for the 25-year period 1978–2002; to analyze the SSPE incidence prior to, and in the period of, routine measles immunization; and, to analyze the clinical characteristics of SSPE. SSPE was diagnosed in a total of 40 children; 28 of were diagnosed between 1978 and 1984, and 12 between 1995 and 2002. Thirty-eight cases (95%) were non-immunized and have had an early measles infection (mean age 16 months). The SSPE onset occurred primarily between 8 and 11 years of age (52.5%) with a mean latent period of about 7 years after the measles infection. After the 10-year disease-free period (1985–1994), the SSPE incidence increased between 1995 and 2002 because of the 1991–1992 measles epidemic. During the period 1995–2002 children with earlier measles infection and earlier SSPE onset predominated, compared to the period 1978–1984. The initial clinical manifestations included intellectual deterioration in 35%, extrapyramidal hyperkinesias in 29%, epileptic seizures in 15%, hemiparesis in 10%, and visual disturbances in 10% of the cases. Nine children (22.5%) demonstrated an atypical onset. A rapidly progressive course was observed in 4 children (10%) and a chronic progressive course with pseudo-remissions over 2 years-in 8 cases (20%). Our analysis of the SSPE incidence in Bulgaria for the 25-year period (1978–2002) supports the importance of early measles infection as a crucial risk factor for this persistent neuroinfection. Moreover, it confirms the role of routine measles immunization in SSPE prevention.