Monomelic amyotrophy: non progressive atrophy of the upper limb.

Monomelic amyotrophy is a rare clinical entity, resulting in wasting and weakness localized to the hand and forearm unilaterally, in the absence of any sensory or long tract signs. The onset of the disease is insidious, occurring in males before the age of 30 years, with a clinical course marked by non-progression. The case of a 19-year-old Indonesian male patient is presented, with a one year history of right upper limb weakness. Nerve conduction studies were normal, without evidence of conduction block. Electromyography showed changes of chronic partial denervation. Magnetic resonance imaging scans revealed an asymmetry of the spinal cord. Possible aetiological mechanisms for these changes are discussed. Copyright 1999 Harcourt Publishers Ltd.