A Rare Case of Severe Calciphylaxis in an Adolescent With AKI

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Introduction: Calciphylaxis is a rare, life-threatening condition characterized by vascular calcification and occlusion of microvessels in the subcutaneous adipose tissue and dermis, resulting in ischemia and painful skin necrosis, mainly diagnosed in end-stage kidney disease. We present a case of a woman without a history of reduced GFR who developed calciphylaxis in the setting of critical illness with acute kidney injury (AKI). Case Description: An 18-year-old woman with morbid obesity (BMI 70) presented with acute hypoxic respiratory failure and shock. Her course was complicated by three weeks of dialysis-dependent AKI. On the first day of dialysis, multiple bullae and erosions overlying retiform violaceous patches were noticed on her bilateral thighs. These progressed to necrotic eschars in 2-3 weeks. Multiple skin biopsies had features of thrombotic vasculopathy without evidence of vasculitis or calciphylaxis. A bone marrow biopsy, viral and autoimmune serologies, hypercoagulability evaluation, and anti-phospholipid antibody syndrome panel were unrevealing. Although her AKI had clinically recovered, a kidney biopsy was performed to find a unifying diagnosis. It showed 10% interstitial fibrosis and tubular atrophy, IgA nephropathy (IgAN), and acute tubular injury without crescents or vasculitis. Her skin wounds continued to worsen despite debridement, empiric steroid therapy, and resolution of her AKI and critical illness. Another skin biopsy captured calcium deposition along deep vessels to finally make a diagnosis of calciphylaxis five months later. Discussion: This case underscores the importance of a high index of suspicion for calciphylaxis with concerning skin findings even in the absence of classic risk factors. Also, a negative Van-Kossa stain for vascular calcium deposits is not necessary to make a diagnosis and initiate empiric treatment. Our patient's risk factors were gender, morbid obesity, transient AKI-related hyperphosphatemia and secondary hyperparathyroidism, ischemia from hypotension, and, potentially, an autoimmune disorder IgAN. However, many patients have these risk factors and never develop calciphylaxis. Therefore, more research is needed to elucidate the epidemiology and pathophysiology of this highly morbid condition.

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