Neuromuscular disease in tertiary hyperparathyroidism.

A 38-year-old woman with chronic renal failure had disabling proximal myopathy of the lower extremities. Investigation revealed "tertiary hyperparathyroidism". Neuromuscular evaluation, including clinical examination, electromyogram, and muscle biopsy, revealed neuropathic muscle disease. These findings are quite similar to the neuromuscular changes in primary and secondary hyperparathyroidism. This suggests that the same neuropathic mechanism may be present in all forms of parathyroid hyperfunction.