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Words on Wounds

A forum to discuss the latest news and ideas in skin and wound care.

Friday, September 25, 2020

Wound CSI: This Doesn't Look Like a Pressure Injury

Recently I was asked to see a woman in the hospital with a necrotic nodule on the back of her calf. Initially, the wound was thought to be caused by pressure from immobility, and the location of the wound did make this area vulnerable to ischemia secondary to pressure damage and resulting in skin necrosis. The area had well-demarcated lesions covered with strangely shaped black leathery eschar; most pressure injuries typically present in geometric shapes. On palpation, the area was indurated and lumpy, with an area of fluctuance. One of the most unusual symptoms was the intense pain over the injured area; even a light stroke was excruciating. Her medical history was complex, including diabetes mellitus, obesity, thyroid disease, hypertension, and renal failure that required hemodialysis for 8 years. 

Overall, her cutaneous lesion was inconsistent with pressure injury but seemed suggestive of calciphylaxis.  

Calciphylaxis most commonly occurs in patients with diabetes mellitus, obesity, autoimmune conditions such as systemic lupus erythematosus, hypercoagulable conditions, hepatitis, hypoalbuminemia, and end-stage renal disease, especially those who require hemodialysis. Although the exact pathogenesis is uncertain, calciphylaxis is an inflammatory disease of small- and medium-sized arteries characterized by vascular calcification, thromboembolism, and painful cutaneous ulcerations. Metabolic disturbances such as hyperglycemia, hyperphosphatemia, hypercholesterolemia, hypertension, and parathormone resistance are common. Evaluation of calciphylaxis starts with a careful medical history and clinical assessment and may require a skin biopsy for a definitive diagnosis. Evaluation may also include a panel of bloodwork including renal functions, mineral bone parameters, liver enzymes, and coagulation screen. Many patients with calciphylaxis could benefit from intravenous sodium thiosulfate, a chelating agent of calcium. Hyperbaric oxygen therapy may help to increase oxygen delivery to the affected parts of the body. Cinacalcet is considered to treat secondary hyperparathyroidism. Bisphosphonates have also been used to regulate serum calcium and phosphorous levels. Management will often involve an interprofessional and multiinterventional approach. 

For this patient, we made a local incision and drained approximately 300 cc of thick, purulent, and malodours fluid.  Because of her intense pain and inflammatory response, we decided to use collagenase to promote enzymatic debridement. The condition of the wound bed improved over the next few weeks, and the removal of nonviable unhealthy tissue exposed fragments of calcified tissue. Next, we used a silver dressing to reduce bacterial burden to control local infection. The patient continued to receive hemodialysis.