Two Babinski signs in seropositive (HAM) and seronegative tropical spastic paraparesis.

Tropical spastic paraparesis (TSP) may or may not be associated to HTLV-I antibodies and is usually characterized by clinical and pathological spinal cord abnormalities at thoracic levels. We present here five Brazilian patients who had typical chronic idiopathic spastic paraparesis; two of them were HTLV-I seropositive (HAM) and three HTLV-I seronegative (TSP) -associated-myelopathy. Three out of these five patients also displayed clinical supraspinal involvement, indeed, platysma muscle hypotrophy or atrophy (the Babinski plus sign). These findings support the view that clinical involvement in HAM and TSP is wider than the spinal cord abnormalities usually considered. Possible non-infectious co-factors (e.g., mycotoxins) may be involved in disease pathogenesis in a multistep process of viruses, toxins and environment which may account for serological differences found in this group of patients.