Spinocerebellar syndrome in patients infected with human T-lymphotropic virus types I and II (HTLV-I/HTLV-II): report of 3 cases from Panama

Cerebellar symptoms at onset are unusual in HTLV-I/II-associated tropical s pastic paraparesis (TSP). A prospective study of neurological disorders in Panama (1985-1990) revealed 13 patients with TSP and 3 with HTLV-I/II-assoc iated spinocerebellar syndrome (HSCS) presenting at onset loss of balance, wide-based stance and gait, truncal instability, and mild leg ataxia (vermi an cerebellar syndrome), with absent upper limb dysmetria but with postural tremor, downbeat nystagmus, and dysarthria. In 4-5 years, spinal cord mani festations of TSP developed, including spastic paraparesis, pyramidal signs , bladder and sphincter disturbances. Two patients were infected with HTLV- I and another one, a Guaymi Amerindian woman, with HTLV-II. Magnetic resona nce imaging (MRI) demonstrated cerebellar atrophy involving predominantly t he superior vermis. Mild axonal peripheral neuropathy in the lower limbs, d orsal column involvement and inflammatory myopathy were found by neurophysi ology studies. There are 14 similar cases reported in Japan and Canada, but to our knowledge these are the first documented cases of HSCS in the tropi cs. A cerebellar syndrome constitutes another form of presentation of HTLV- I/II infection of the nervous system.