Pure Neuritic Leprosy with Bilateral Foot Drop and Central Nervous Involvement: A Clinical, Electrophysiological, and MR Correlation

Background: Central nervous system (CNS) involvement in leprosy is sparsely documented. Neurophysiological tests and magnetic resonance imaging (MRI) helps in demonstrating CNS involvement in the patient of pure neuritic leprosy. Objectives: To demonstrate CNS involvement in pure neuritic leprosy. Methods: Detailed clinical presentation and skin lesions were evaluated. Sural nerve biopsy, MRI diffusion tensor imaging of spinal cord and optic nerve were performed. Visual evoked potential and tibial somatosensory evoked potential were done. Their clinical, electrophysiological, and MRI were done at follow-up visits. Results: We report three patients of pure neuritic leprosy with bilateral foot drop as the initial presentation. MRI T2W sequence of cervico dorsal cord showed dorsal column hyperintensity in two patients. Diffusion-weighted MR revealed decrease fractional anisotropy and an increase in the apparent diffusion coefficient. Similar findings were also noted in the optic nerves. The patients were managed with multidrug therapy multibacillary regimen and steroid in tapering dose. At follow-up, they showed clinical improvement in vision and power of ankle dorsiflexor. Conclusions: Patients of pure neuritic leprosy may manifest with bilateral foot drop with the involvement of posterior column and cranial nerves.