Calciphylaxis: a syndrome of skin necrosis and acral gangrene in chronic renal failure.

BACKGROUND: Calciphylaxis is a rare condition of rapidly extending ischemic skin necrosis or acral gangrene of fingers, toes or penis in patients with chronic renal failure. It may be accompanied by extensive metastatic calcification of soft tissues. Histology of infarcted tissues shows prominent medial calcification and intimal hyperplasia of subcutaneous arteries and/or digital arteries, respectively. The pathogenesis of calciphylaxis is only poorly understood. Most patients have hyperparathyroidism and an elevated calcium-phosphate-product, which is thought to be a major pathogenetic factor of calciphylaxis. PATIENTS AND METHODS: All published cases of calciphylaxis including nine of own (155 patients in total) from 1936 through 1996 were reviewed and subjected to statistical meta-analysis (Fisher's exact test).
RESULTS: Proximal locations of necrosis (thighs, buttocks, trunk) carried an unfavourable prognosis (63% mortality) compared to distal locations (calves, forearms, fingers, toes, penis) with 23% mortality (p < 0.0001). Parathyroidectomy was associated with a favourable outcome (p < 0.004). Diabetics with chronic renal failure had acral gangrene in 61% compared to 34% of the non-diabetic calciphylaxis-patients (p < 0.007).
CONCLUSIONS: The present analysis of all published cases of calciphylaxis is limited by patient selection and publication bias. The unfavourable prognosis of patients with proximal necrosis is impressive and might justify an early and aggressive treatment in such cases. However, the general benefit of parathyroidectomy remains debatable. Hyperparathyroidism should be managed primarily by conservative means. Parathyroidectomy should be reserved for patients with very high parathyroid hormone level and calcium-phosphate-product or with a rapidly progressive disease.