Clinical and electroencephalographical characterization of typical absence seizures

Abstract

The human T-lymphotropic virus type I (HTLV-I) is the etiologic agent of tropical spastic paraparesis / HTLV-I associated myelopathy (TSP/HAM), adult T cell leukemia/lymphoma (ATLL) as well as of other immunomediated systemic diseases. Contrary to other pathogenic viruses to man HTLV-I apparently causes diseases in the minority of the infected population. The real prevalence of HTLV-I neurologic manifestations is still reason for debate in the literature with percentages ranging from 0.07% to 2.6%. The relation between an increased risk for development of disease and other contributing cofactors is also speculated. The continuous prospective observation of infected individuals has suggested to us that the prevalence of neurological manifestations might be higher than what is presently assumed. In order to evaluate the prevalence of signs and symptoms of neurological involvement in a population of blood donors from the largest blood bank from the city of Rio de Janeiro, Brazil (HEMORIO) and also the possible correlation of epidemiological variables which could possibly contribute to a higher risk of development of neurological disease we designed the present study.Between May 1995 to December 1997, 392 blood donors from HEMORIO were selected by a cross sectional study. Fifty percent of these individuals were HTLV-I positive. For the prevalence study, neurologically impaired HTLV-I positive individuals were considered cases and HTLV-I positive individuals with a normal neurological examination, controls. Cases were classified in symptomatics and asymptomatics, and according to the topographic diagnosis (involvement of the central [CNS], peripheral [PNS] nervous system or muscle). Patients underwent specific laboratory investigations. The method of case-control study was employed for the evaluation of risk factors for the presence of neurological disease. For this part of the study HTLV-I positive patients were classified as cases, and seronegative asymptomatic individuals as controls.Neurological disease was found in 71 (36.2%) out of 196 seropositive individuals. Of these, 34 (48%) individuals had involvement of the CNS (11 [32.3%] TSP/HAM cases); 33 (46%) patients with involvement of PNS (18 [54.5%] cases of polyneuropathy) and 4 (6%) patients with muscular disease (one case of polymyositis). Previous use of intravenous drugs (OR 9.9 and CI95% 1.9-68.5), family history of either HTLV-I infection or HTLV-I associated disease (OR 7.5 and CI95% 3.1-18.8), risky sexual behavior (OR 6.9 and CI95% 2.5-20.4), hemotransfusion in the past , and a history of either HTLV-I infection or HTLV-I associated diseases (OR 9.9 and CI95% 1.8-11.6) were significantly associated to the presence of neurological disease among HTLV-I seropositives. Hypergammaglobulinemia and ophthalmologic abnormalities were also significantly associated to the presence of those neurologic disorders.Our data suggest that the exposition to HTLV-I was significantly associated to the development of neurological disease in a higher proportion than what has...