Overview
HTLV-1-associated myelopathy/tropical spastic paresis (HAM/TSP) is a chronic inflammatory disease of the central nervous system that only occurs in people living with HTLV-1 infection.
Incidence
Lifetime prevalence is estimated to be approximately 2% among people with HTLV-1. There is significant variation in the reported prevalence, from 0.25% in Japan to 1.8% in Trinidad. There is evidence that HAM/TSP is associated with a higher pro-viral load.
Mortality
While HAM/TSP causes significant morbidity it is unclear whether there is a direct effect on mortality.
Symptoms
Initial presentation is often urinary symptoms or an impaired gait, as perceived by the patient.
Clinical features generally include slowly progressive weakness and spasticity in one or both legs, back pain with or without radiation, bladder dysfunction (spastic or flaccid) and bowel dysfunction, normally constipation.
Examination shows hyperreflexia, ankle clonus, extensor plantar responses and loss of vibration sense.
Diagnosis
Clinical diagnosis is based on the WHO consensus criteria of neurological signs and cerebrospinal fluid examination. Newer technologies developed after the WHO criteria including serum and cerebrospinal fluid proviral load and MRI may also be useful.
Treatment
There is no treatment proven to alter the natural history of HAM/TSP. However, systemic corticosteroids are recommended in patients with progressive disease as there is some evidence they may slow progression.
Management and Care
Support and management of the neurological deficits are an important component of care.
