Motor neuropathies mimicking amyotrophic lateral sclerosis/motor neuron disease

We report three patients in whom the initial diagnosis was of possible Amyotrophic lateral sclerosis (ALS/MND) according to the ‘El Escorial Criteria’. All of them presented with monomelic paresis, atrophy of the paretic muscles and generalised brisk reflexes. The initial electromyograms showed a neurogenic pattern in the limbs with normal sensory and motor conduction velocities. Laboratory evaluation and imagiological investigations were normal in all of them. The previous diagnosis was changed in to demyelinating motor neuropathy with conduction block in 2 patients and tomaculous neuropathy in one after clinical and electromyographic follow-up and nerve biopsy. Patients 1 and 2 were given intravenous immunoglobulin treatment and showed moderate improvement.