Human T Cell Lymphotropic Virus Type 1-Associated Myelopathy in São Paulo, Brazil

We report epidemiologic and clinical features of human T cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis in a Brazilian cohort of 86 patients from a university hospital. Cerebrospinal fluid (CSF) abnormalities and magnetic resonance imaging (MRI) findings were correlated with neurologic signs and symptoms. The patients’ mean age at disease onset was 43.2 years and the female to male ratio 1.5:1. Risk factors for retroviral exposure included blood transfusions, sexual transmission and intravenous drug use. Neurologic manifestations consisted mostly of spastic paraparesis, of gradual and asymmetric onset, with increased deep-tendon reflexes. Disability was associated with disease duration. CSF findings included mild mononuclear pleocytosis and elevated protein levels. MRI showed hemispheric areas of high signal intensity in 32.7% and spinal cord atrophy in 5.6% of cases, particularly in patients with longer duration of disease. A high frequency of past blood transfusion (32.6%) suggests that blood-borne infection was an important means of HTLV infection before implementation of screening of blood donors in Brazil.