Calciphylaxis

Key Points
Lifethreatening condition associated with hyperparathyroidism
Exact cause is unknown, but calcification in the capillaries causes necrosis in the skin
Primarily found in persons in the final stages of kidney disease
Consists of purple mottling of the skin, progressing into bleeding, and then turning black

Calciphylaxis is a rare disorder, closely associated with hyperparathyroidism, in which damaged kidneys cause an excess of phosphate in the blood, thereby enlarging the parathyroid glands and leading to build up of calcium in the bloodstream. As smaller blood vessels become blocked with clots because of calcification, the surrounding tissue becomes necrotic. The condition begins as a purplish mottling of the affected area, which progresses to bleeding, after which the skin turns black in the center and lesions become roughly star-shaped. As the tissue dies, lesions become extensive and deeply ulcerated. Affected persons will experience severe pain and burning in the affected areas, with occasional itching. Lesions forming on the trunk or buttocks and thighs are often more dangerous than those occurring in the lower extremities.

Calciphylaxis primarily affects those persons in the final stages of kidney disease. It is more common in those persons who have not begun dialysis or have had renal transplants. It appears to affect women more than men, obese persons, and persons being treated with corticosteroids or other immunosuppressants.

Differential Diagnosis (Other conditions with similar appearance)
Necrotizing fasciitis
Cryoglobulinaemia
Vasculitis
Antiphosopholipid syndrome
Coumarin necrosis

Diagnosis
Key Points
Diagnosis initially based on skin appearance
Skin biopsy may be performed to confirm diagnosis and rule out similar appearing conditions
In some cases, radiological tests may confirm calcification of vessels

Calciphylaxis is initially diagnosed based on the appearance of affected areas, then confirmed through skin biopsy to detect the presence of calcium. X-rays may confirm calcification of vessels in the affected areas, though this may not always indicate a positive diagnosis, as calcification can appear in other renal disease patients.

Treatment
There is no clear course of treatment
Primary goal of treatment is to return phosphate and calcium levels to normal, and wound management
In early cases, removal of the parathyroid glands may assist in healing and reduce pain
*Anticoagulants may reduce clotting, but are not always recommended

Treatment of Calciphylaxis is difficult, and health care professionals have few options which are effective. The primary goal of treatment is reducing the levels of phosphate and calcium in the bloodstream, which is accomplished by restricted diet and specified dialysis treatments. Wound management is also extremely important, and health care professionals will remove necrotic tissues, keep the wound clean and dressed, and prescribe systemic Antibiotics to fight infection. Removal of necrotic tissue can involve limb amputation.

The removal of the parathyroid glands can assist in reducing pain and encouraging the healing of wounds, especially if performed in the early stages of the disease, though this is not an option in persons not experiencing hyperparathyroidism in association with the disease.

Other treatments with varying levels of success include reducing blood clots with anticoagulants, use of biphosphonates, and intravenous administration of sodium thiosulfate.