SKIN NECROSIS - AN UNUSUAL COMPLICATION OF HYPERPHOSPHATEMIA DURING TOTAL PARENTERAL-NUTRITION THERAPY

Background:. Hyperphosphatemia complicated by calcification of subcuta neous arteries and skin infarcts are very rarely reported in the absen ce of chronic renal failure (CRF). We describe identical lesions in an obese woman with sepsis. Hyperphosphatemia resulted from an unintende d excess of phosphate in her total parenteral nutrition (TPN) formulat ions. She did not have CRF or hyperparathyroidism. Methods: The patien t's records during 37 weeks of hospitalization 12 gears ago and, subse quently her outpatient records were reviewed. Results: During a 7-week period, the total elemental phosphorus infused daily, as divalent pho sphate, ranged from 1.8 to 4.2 g, median 3.1, over triple the normal d aily requirement. This excess was unintended. This occurred before the current practice of pharmacist-monitoring of TPN formulations, and po ssibly resulted from misinterpretation of a revised formulation sheet, newly introduced to the nursing units at the start of that period. Se rum phosphorus increased to 3.02 mmo/L (normal 0.76 to 1.46 mmol/L). S he developed calcification of subcutaneous arteries, which was complic ated by widespread infarcts of the anatomically related skin and subcu tis, apparently the result of hypoperfusion of these vessels during an episode of septic shack. The infarcts were heralded by unusual, blotc hy skin discolorations. Conclusions: This report, illustrating a start ling cutaneous complication associated with apparent misinterpretation of TPN formulations, demonstrates a pathogenetic relationship between hyperphosphatemia, calcification of subcutaneous arteries, and necros is of the skin and subcutis in the absence of CRF and hyperparathyroid ism and introduces a new differential diagnosis for unusual skin lesio ns appearing during TPN therapy.