RHE2 Use of MRI in the diagnosis of calciphylaxis. (Rheumatology).

RHE2 USE OF MRI IN THE DIAGNOSIS OF CALCIPHYLAXIS. Basanti Mukerji, MD, Luis Manyari, MD, and Mark Weaver, MD. Southern Illinois University School of Medicine, Springfield, Ill.

A 38-year-old woman on hemodialysis for ten years for end-stage renal disease was admitted with a week long history of increasing pain in her legs. On admission she was unable to walk. She denied trauma, paresthesias, weakness, or fever. She bad hypertension and diabetes. One year earlier she underwent partial parathyroidectomy for secondary hype parathyroidism and a high calcium (Ca) x phosphorus (P) product. After this surgery the Ca x P product remained moderately high due to lack of compliance with medical therapy. Physical examination revealed indurated plaques on both lower extremities that were confluent over the right thigh, and exquisitely tender to touch. Due to pain, muscle strength of the thighs and legs could not be assessed. Pedal pulses were normal. To assesss the depth of tissue involvement, an MRI of her legs was obtained. This showed edema of the skin and subcutaneous tissue, with sparing of the muscles and fascia. The edema was manifest in a characteristic patchy pattern not seen in other c onditions. Serum creatinine phosphokinase, hemoglobin AlC, thyroid-stimulating hormone, parathyroid hormone, Ca, and P values were normal. Antinuclear antibody, hepatitis and HIV serology were negative. The skin biopsy showed calciphylaxis with calcium deposits in the walls of the small vessels and collagen fibers, with minimal inflammatory cell response and some fat necrosis. Calciphylaxis is a rare cutaneous phenomenon associated with chronic renal failure. There is abnormal calcium deposition in the walls of small vessels with subsequent ischemia and tissue necrosis. It can mimic other forms of panniculitis and vasculitis. It usually occurs in patients with end-stage renal disease who have a high Ca x P product. There is considerable morbidity and mortality from the disease due to skin ulceration with subsequent sepsis. Preventive measures include oral calcium-aluminum free phosphate binders and hemodialysis with low-dialysate calcium. Treatment includes pain control, parathyroidectomy if the parathyroid h ormone level is high, systemic antibiotics, and aggressive wound care. Our findings in this patient suggest that in the appropriate clinical setting, the diagnosis of calciphylaxis may be made by MRI. This may be preferred to actual biopsy because of the increased risk of wound infection and nonhealing in these patients.