Final Diagnosis

Systemic calciphylaxis affecting skin and muscle

Patient Follow-up

The patient underwent multiple skin wound debridements and parathyroidectomy. Despite these treatment measures, the patient died from sepsis 4 months after the initial presentation.

Discussion

Calciphylaxis is a rare disorder that predominantly affects patients on dialysis for chronic renal failure [1, 2]. It is characterized by systemic vascular calcification. The disorder carries a high morbidity and mortality especially in patients with ulcerative skin lesions. Clinical manifestations most commonly affect the skin, however vascular calcifications can affect any organ in the body including skeletal muscle, brain, lung, mesentery, and eyes [1, 3–5].

Muscle involvement in calciphylaxis can present with a painful proximal myopathy that progresses over several months. Media1 calcification and intimal proliferation of arterioles cause luminal narrowing which leads to muscle ischemia and resultant pain [6]. Although mural calcification predominantly involves small arterioles, it can also affect small venules and capillaries [6, 7]. A few case reports described patients with calciphylaxis who developed prominent muscle involvement manifesting with weakness, myalgias, and rhabdomyolysis [6–11]. In one case the myopathy symptoms preceded the development of skin lesions and were the first presenting symptoms of calciphylaxis [8]. Although a myopathy with skin abnormalities raises a concern for dermatomyositis [9], the ischemic necrotic skin lesions seen in calciphylaxis (Fig. 20.1a) are very different from skin rashes seen with dermatomyositis.

Laboratory studies may show higher levels of PTH, calcium, and phosphorous but are not reliable indicators of calciphylaxis. Definitive diagnosis of calciphylaxis requires a skin biopsy, which shows arteriolar medial calcification, intimal fibrosis and thrombotic occlusion [12]. However, as in this case, advanced tissue necrosis can cause the sample to be non-diagnostic. Muscle biopsy can be useful in such cases especially when myopathy is suspected to be a part of the clinical picture. Muscle biopsy shows calcification of the walls of perimysial arterioles, venules, and endomysial capillaries [6, 7].

Management includes wound debridement, pain control, dialysis, nutritional management, and parathyroidectomy in patients with refractory hyperparathyroidism. However, despite these measures, morbidity and mortality remain high.

Pearls