Bryan J. Michelow, MD., FACS

Bryan J. Michelow, MD., FACS

Monday, June 16, 2014

Calciphylaxis - an unusual but interesting condition

During my elective rotation at Dr. Michelow’s office, I was able to see a large amount of patients with a vast array of conditions.

One particular case that sparked my attention was a woman with presumed calciphylaxis of the lower abdomen. I was so intrigued by this condition that I decided to do my end of rotation presentation on calciphylaxis. 

Here is what I found:
Calciphylaxis is a condition where calcium is deposited in the subcutaneous and cutaneous tissue, as well as in the vessel walls. The continued calcification leads to vascular occlusion which impedes blood flow and ultimately leads to necrosis of the tissue. 

The exact etiology of calciphylaxis is unknown, however there are many risk factors that predispose a patient to this condition. The most noteable risk factor is chronic kidney disease, especially those patients requiring dialysis. The kidney does not properly excrete calcium and phosphate and often the dialysate utilized is high in phosphate and/or calcium. The calcium and phosphate then bind and precipitate, thus causing vascular occlusion. 

Another risk factor includes uncontrolled Warfarin levels. Warfarin inhibits a vitamin-K dependent factor that is responsible for inhibiting vascular calcification. 

Additional risk factors for calciphylaxis include alcoholic liver disease, diabetes mellitus, connective tissue disorders, glucocorticoid use, chronic inflammatory conditions, and clotting disorders.

Calciphylaxis typically presents as a tender, erythematous areas of skin. The lower extremities are most commonly affected (90%). Other areas that may be involved include the abdomen and the buttocks. These lesions progress to reddish-purple plaques and ultimately end up as a black stellate eschar overlying gangrenous ulcers and patches of ischemic necrosis.

Diagnosis is typically made by deep tissue biopsy. Incisional biopsy of the skin could result in a non-healing ulcer which increases risk of mortality 2-fold. Additional diagnostic tests that may help include plain films showing calcium deposits in the vessels.

The goal of treatment of calciphylaxis  is to lower calcium and phosphate in the blood. This is accomplished by Cinacalcet, which makes receptors more sensitive to calcium, and Sodium Thiosulfate which increases the solubility of calcium deposits. A non-calcium phosphate binder such as Sevelamer will decrease phosphate levels. Wound management should be optimized and prophylactic antibiotics may be necessary to prevent secondary infection. Surgery may be considered to excise the areas of vascular compromise if the patient is fit for surgery.

Unfortunately, the mortality rate for calciphylaxis is 85%. The 1-year survival rate is 45% while the 5-year survival rate is only 35%. The most common reason for mortality is sepsis. Factors that increase mortality rate include proximal lesions and ulceration.

The plan for the patient that I saw was to undergo a deep tissue biopsy to confirm the diagnosis. Once confirmed, she will be started on Cinacalcet or Sodium Thiosulfate. Wound management will be optimized with a multi-disciplinary approach and strict adherence to the medical regimen. Her prognosis is guarded.

Julie Shawver PA-S

Mount Union Physician Assistant Program