Clinical, electroneuromyographic and morphological studies of pure neural leprosy in a Brazilian referral centre.

Nineteen patients with pure neural leprosy were analysed with clinical examination, electroneuromyography and histopathology of nerve biopsies. Clinical examination showed sensory loss (78.9%), paresis (78.9%), nerve enlargement (68.4%) and nerve pain (42.1%). Electroneuromyographic study revealed an axonal pattern in 18 patients (94.7%) and a demyelinating pattern in one (0.5%). Mononeuropathy multiplex was the most frequent presentation (78.9%), followed by mononeuropathy simplex (10.5%) and polyneuropathy (10.5%). The histopathological study showed the presence of inflammatory infiltrate composed of epithelioid granuloma (42.1%), mononuclear infiltrate (36.8%) or macrophages positive for bacilli (21%). Fibrosis was present in 78.9% of the biopsies. Examination of semithin sections revealed, besides inflammatory infiltrate, myelinated fibre loss (94.7%), remyelination (42%), axonal degeneration (10%) as well as regeneration (31.5%). Based on these results, the pathogenesis of leprosy neuropathy in this group of patients is briefly discussed.