Severe proximal myopathy in advanced renal failure. Diagnosis and management

Myopathies encountered in uremic patients may have different pathogenetic mechanisms and treatment. Secondary hyperparathyroidism may cause uremic myopathy responding to specific treatment. This study aimed at presenting a case illustrative of the clinical features, diagnosis and management of uremic parathyroid myopathy. A 66-year old man with renal failure from membranous nephropathy developed sensory signs of uremic neuropathy and progressive painless weakness of the pelvic girdle muscles bilaterally. Motor nerve conduction velocity was normal, electromyogram was consistent with a myopathic pattern, while muscle biopsy showed a pattern of atrophy more consistent with a neuropathic pattern. Serological tests for collagen vascular diseases and hyperthyroidism were negative, while serum muscle enzymes were not elevated and serum phosphate levels were not low. Serum parathyroid hormone level was grossly elevated, while serum calcium was mildly elevated in a small fraction of the measurements, serum alkaline phosphatase showed a progressive rise and skeletal bone survey did not disclose osteopenia or signs of parathyroid bone disease. A course of calcitriol failed to improve the myopathy, which responded promptly and dramatically to parathyroidectomy. Uremic parathyroid myopathy, which has a characteristic clinical picture, must be differentiated from other neuropathic or myopathic conditions that require specific treatments. Progressive parathyroid myopathy is, by itself, an indication for parathyroidectomy, which is curative in this case.