SAT214 A Rare Case Of Biopsy-proven Non-uremic Calciphylaxis In A Patient With Secondary Hyperparathyroidism

Disclosure: U.A. Ogar: None. A.G. Olafimihan: None. I. Asemota: None. E. Krishnaraju: None. A. Okafor: None. Introduction: Calciphylaxis, also known as calcific uremic arteriolopathy, is a rare, lethal, metastatic calcification involving cutaneous microvasculature that presents as painful necrotic skin lesions. It typically occurs in patients with end-stage kidney disease (ESKD), renal transplant, or acute kidney injury requiring renal replacement therapy. Calciphylaxis occurring without these comorbidities is termed non-uremic calciphylaxis (NUC), which is rarer. NUC’s etiology is unclear but it has been associated with hyperparathyroidism, malignancies, alcohol liver disease, and connective tissue disorders. There are only a few reported cases of biopsy-proven NUC in patients with secondary hyperparathyroidism, as in our patient. Clinical Case: A 63-year-old female with a history of COPD on home oxygen therapy, smoking, and alcohol use disorder presented with a four-day history of severe, painful, purplish left thigh rash. She had no recent trauma or insect bite. Her physical exam showed a large (6x10 cm), tender, distal anterior left thigh bruise. Laboratory findings were significant for elevated creatine of 4.3 mg/dL from a normal baseline creatinine (0.6 mg/dL), normal serum corrected calcium (10.1 mg/dL) and elevated phosphate (4.7mg/dL). Three days following her admission, the skin lesion had progressed into multiple brown coalescing bullae with central ulceration, collarette, surrounding erythema, warmth, and induration. Due to concern for possible skin and soft tissue infection, empiric vancomycin therapy was started. However, the overall clinical picture was not convincing of an infection, necessitating consultation with the Dermatology team. A skin biopsy was recommended, and this was diagnostic of calciphylaxis. Further testing revealed hyperparathyroidism (202pg/ml), low 25 hydroxy Vitamin D (12ng/ml), and negative autoimmune and thrombophilia workup. Her treatment plan included wound care with debridement, analgesia, and interdisciplinary clinic follow-up. During outpatient follow-up, her wound was seen to be slowly healing with daily wound dressing, and her elevated serum creatinine had resolved. Conclusion: NUC has a high mortality rate (52%) and requires a high index of clinical suspicion to ensure prompt diagnosis and initiation of treatment. Differential diagnoses include atherosclerotic vascular disease, vasculitis, hypercoagulable disorders, and cellulitis as in our patient. Skin biopsy is diagnostic. Aggressive wound care and analgesia are pivotal to treatment, in addition to addressing underlying precipitating conditions. Other treatment options like sodium thiosulphate exist but with uncertain outcomes. Efforts geared at definitive therapeutic modalities are needed. Presentation: Saturday, June 17, 2023