Dermatology Online Journal

Metastatic calcification
Elizabeth K Hale MD
Dermatology Online Journal 9(4): 2

From the Ronald O. Perlman Department of Dermatology, New York University

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Abstract

Calciphylaxis is a rare, painful, and debilitating disease of widespread metastatic calcification that progresses to ischemic tissue necrosis. It occurs almost exclusively in patients with end-stage renal disease and secondary hyperparathyroidism. Reticulated, violaceous, mottled patches commonly appear on the lower extremities and progress to cordlike nodules and necrotic ulcers with overlying eschars. Septicemia, which may occur after secondary infection of the ulcers, is the most common cause of death. Treatment with phosphate-binding antacids, total or partial parathyroidectomy, and avoidance of local tissue trauma remain the mainstays of therapy, although a uniform cure for calciphylaxis remains elusive. Prognosis for patients with calciphylaxis is dismal, even after surgical intervention. Early diagnosis and treatment is critical to prevent progression of the disease process.

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Clinical summary

History.—A 52-year-old man first presented to the dermatology clinic complaining of tightness in his legs in August 2001. The pain was bilaterally symmetric and had not been progressing. A skin biopsy was performed to confirm the suspected diagnosis. Chronic renal failure was diagnosed 9 years ago, and the patient has been treated with hemodialysis since that time. He has been followed in both the medical and surgical clinics for evaluation of secondary hyperparathyroidism and is currently being evaluated for a possible parathyroidectomy. His medical history includes diabetes mellitus, hypertension, and coronary artery disease.

Physical examination.—Indurated plaques, without overlying erythema or necrosis, were present on the medial aspects of both lower extremities. Scattered excoriated nodules were also noted. Palpation of the vessels suggested hardening. There were no erosions, ulcers, or breaks in skin integrity.

Figure 3a	Figure 3b

Laboratory data.—The blood urea nitrogen was 65 mg/dl, creatinine 9.1 mg/dl, serum calcium 10.5 mg/dl, and phosphorus 11.0 mg/dl. Parathyroid hormone was elevated at 2845 pg/ml.

Histopathology.—There are calcium deposits in the subcutaneous lobules associated with necrosis and some vacuolated macrophages. Some calcium deposits are also identified in the walls of small capillaries and along some collagen fibers.

Diagnosis.—Metastatic calcification

Comment

Metastatic calcification usually is a generalized phenomenon occurring throughout the body, but it primarily affects the interstitial tissue of the blood vessels, kidney, lungs, and gastric mucosa. Metastatic calcification may progress to calciphylaxis, which is a rare, painful, and debilitating disease of widespread metastatic calcification that progresses to ischemic tissue necrosis. It is seen almost exclusively in patients with end-stage renal disease and secondary hyperparathyroidism. Affected patients usually present with painful, violaceous, mottled lesions of the extremities or trunk that progress to skin and subcutaneous tissue necrosis and often undergo ulceration. Patients with lesions restricted to skin below the midcalf and fingers (distal type) have a much better prognosis than do those with extensive lesions occurring on the trunk and proximal extremities (proximal type).[1]

Early diagnosis and treatment is critical to prevent progression of the disease process. Furthermore, the disease is painful and debilitating, and inappropriate treatment, such as glucocorticoid administration, may aggravate the condition. [2] Studies have demonstrated that the product of serum calcium and phosphorous concentrations, parathyroid hormone levels, and the anatomical location of the soft tissue lesions do not correlate clinically with wound healing or mortality.[1,3] One group reported that lesion severity at the time of parathyroidectomy appears to correlate best with clinical outcome.[3] Septicemia, which occurs after secondary infection of chronic ulcers, is the most common cause of death, and patients with elevated white- cell counts at the time of diagnosis have a poor prognosis.[4] Treatment with phosphate-binding antacids, total or partial parathyroidectomy, and avoidance of local tissue trauma remain the mainstays of therapy, although uniform cure for calciphylaxis remains elusive. [2] Prognosis for patients with calciphylaxis is dismal, even after surgical intervention. There has been at least one report of successful use of hyperbaric oxygen therapy in the healing of skin ulcers that occurred in the setting of calciphylaxis.[5] Early recognition of the signs and symptoms of calciphylaxis should lead to timely parathyroidectomy in the hopes of ameliorating the symptoms and slowing progression to deleterious sequelae.

References

1. Oh DH, et al. Five cases of calciphylaxis and a review of the literature. J Am Acad Dermatol 1999;40:97.

2. Worth RL. Calciphylaxis: pathogenesis and therapy. J Cutan Med Surg 1991;2:245.

3. Roe SM, et al. Calciphylaxis: early recognition and management. Am Surgeon 1994;60:81.

4. Kriskovich MD, et al. Calciphylaxis: is there a role for parathyroidectomy? Laryngoscope 2000; 110:603.

5. Vassa N. Hyperbaric oxygen therapy in calciphylaxis-induced skin necrosis in a periotoneal dialysis patient. Am J Kidney Dis 1994;23:878.

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