A case report of HTLV-I associated myelopathy presenting with cerebellar ataxia and nystagmus

HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) is characterized by spastic paraparesis in the lower extremities, and urinary disturbance. HAM/TSP has also been less frequently associated with cerebellar syndromes and nystagmus. We report a case of HAM/TSP presenting with cerebellar ataxia and nystagmus. The patient was a 73-year-old woman who was born in southern Japan. At age 41, she developed pain and spasticity in the bilateral lower limbs and gradually progressive gait disturbance. At age 57, she was diagnosed with HAM/TSP based on spastic paraparesis in the lower limbs, urinary disturbance and positive anti HTLV-I antibody in serum and cerebrospinal fluid. In June 2008, she was referred to our university and hospitalized for rehabilitation. Twenty days later, she experienced rotatory vertigo sensation. Magnetic resonance imaging revealed pontocerebellar atrophy. The patient presented with cerebellar signs in the upper limbs, gaze-evoked nystagmus in the sitting position and right-beating horizontal nystagmus in the supine and head-hanging positions. Electronystagmography (ENG) showed horizontal saccadic overshoot dysmetria and horizontal saccadic pursuit. Nystagmus is rare among the literature on HAM/TSP. ENG is helpful to evaluate and confirm the cerebellar syndromes of HAM/TSP.