Avneet Singh, MD, Resident, Colleen McEvoy, BS, Medical Student, Nadish Garg, MD, Resident, Department of Internal Medicine, University of Missouri, Columbia.
An 80-year-old man with diabetes, hypertension, chronic kidney disease, and coronary artery disease was admitted to the hospital for chest pain. segment elevation myocardial infarction. Other medications initiated in the hospital included metoprolol, simvastatin, insulin, and calcitriol for secondary hyperparathyroidism (parathyroid hormone level >150 pg/mL). At 12 hours after admission, a skin lesion was noted at the site of the insulin administration on the abdominal wall (Figure). A biopsy of the lesion revealed the diagnosis.
What's Your Diagnosis?
- Calciphylaxis
- Heparin-induced skin necrosis
- Subcutaneous hemorrhage
- Cholesterol embolization
Quiz Answer
Subcutaneous hemorrhage—The skin biopsy confirmed the diagnosis. The likely precipitating event was subcutaneous insulin injection at that site, in addition to an elevated activated partial thromboplastin time (aPTT) from heparin infusion. Heparin is a known cause of subcutaneous and deep-tissue hematomas in patients with a prolonged aPTT. Unless the patient is hemodynamically unstable, the treatment is usually conservative. In this case, the heparin therapy was stopped, which contained the hemorrhage. The skin biopsy was negative for thrombi or necrosis (heparin-induced skin necrosis), medial calcification (calciphylaxis), and cholesterol clefts (cholesterol emboli).
Calciphylaxis is mostly seen in patients with end-stage renal disease who are on hemodialysis or who have recently received a renal transplant. Calciphylaxis is related to vascular and soft-tissue calcification and can be precipitated acutely by the initiation of calcitriol therapy for secondary hyperthyroidism. The diagnosis is confirmed by skin biopsy, which shows arterial occlusion and calcification in the absence of vasculitic change.
Heparin-induced skin necrosis is a rare entity that has been described only in patients receiving subcutaneous heparin.
Our patient did have atherosclerotic vascular disease that predisposed him to cholesterol embolization, characterized by skin lesions such as livedo reticularis, subcutaneous nodule, and ischemic ulceration. However, cholesterol embolization typically occurs after angiography, cardiac catheterization, vascular surgery, or abdominal trauma. Biopsy in cholesterol embolism shows cholesterol clefts within the vessel.
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