The natural history of peripheral neuropathy in primary systemic amyloidosis.

The records of 31 patients with primary systemic amyloidosis and peripheral neuropathy seen during a 17-year period were analyzed to define the natural history of the neuropathy. Patients tended to be older men with a painful, distal, symmetrical sensorimotor neuropathy and prominent autonomic features. Loss of pain and temperature sensation was frequently more striking than loss of mechanoreception. Renal, cardiac, hematological, and gastrointestinal dysfunction often overshadowed the neuropathy. Clinical, neurophysiological, and histopathological studies pointed to axonal degeneration with predominant but not exclusive involvement of small myelinated and unmyelinated fibers. The neuropathy was progressive in all patients with or without treatment, but death was typically due to supervening medical complications.