neurologic disorders
Overview of Peripheral Nervous System Disorders
Key Points
Peripheral nervous system disorders are often suspected based on clinical findings (eg, stocking-glove distribution, hyporeflexia, distal muscle weakness and wasting, localization to a peripheral nerve distribution). If patients have profound motor weakness with minimal atrophy and areflexia, consider acquired demyelinating polyneuropathy. If patients have abnormal pain and temperature sensation and atrophy in proportion to weakness (sometimes with disproportionate preservation of reflexes), consider a vasculitic or ischemic neuropathy. If patients have chronic progressive muscle weakness, fasciculations, muscle atrophy, and no sensory deficits, consider motor neuron disease. Nerve conduction studies and electromyography help identify level of involvement (root, plexus, peripheral nerve, neuromuscular junction, muscle fiber) and help distinguish demyelinating from axonal disorders. 