Monomelic amyotrophy

Introduction: Monomelic amyotrophy is an uncommon neurological disorder causing wasting and weakness of only one limb, and rarely is bilateral and symmetric. After a slow progression for 2-4 years, it reaches a stationary course and life expectancy is not affected. This disorder should be differentiated from motoneuron diseases. Case report: A 42 year-old man, without history of trauma, infection, radiation or genetic disorders, started at the age of 17 with weakness, atrophy and fasciculations in right upper extremity. This disorder stops progression two years later. After 22 years of stationary course he developed atrophy and fasciculation in the contralateral arm. Bilateral atrophy with normal reflexes and fasciculations were observed in upper limbs. Electromyography revealed chronic denervation in proximal and distal muscles of upper extremities. Cranial nerves, pyramidal, sensitive and cerebellar systems were normal. Discussion: Our patient presented brachial monomelic amyotrophy with symmetrical involvement after a long term stationary period. After one year follow up he appears to reach a second stationary phase. This disorder may be a localized lower motor neuron degeneration affecting spinal cord segments. Recognizing this disease, avoids suffering distress for the possibility of having a progressive and invariably fatal disorder such as amyotrophic lateral sclerosis.