Case Author(s): Michelle Dorsey, M.D. and Tom R. Miller, M.D., Ph.D. , 4/4/03 . Rating: #D4, #Q5

Diagnosis: Calciphylaxis

Brief history:

26 year old woman with painful, erythematous plaques of the lower extremities

Images:

Anterior and posterior images are shown

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View second image(bs). Spot images (left) and coronal (above) and axial (below) SPECT images are shown

View third image(xr). Plain radiographs

View fourth image(ct). Chest radiograph and computed tomography images

Full history/Diagnosis is available below

Diagnosis: Calciphylaxis

Full history:

This 26 year old woman presents with painful, erythematous bilateral leg plaques. They appeared 4 weeks ago, and have been painful for the last 2 weeks. Her past medical history is significant for end-stage renal disease from reflux nephropathy with renal transplant in 4 years ago followed by rejection two years later. The patient has been on peritoneal dialysis for the last 2 years. She also has renal osteodystrophy, and underwent parathyroidectomy last year with a forearm autograft implant. She has had multiple episodes of hypocalcemia raising the question of a non-functioning graft. She is currently on calcitrol. Recent history includes recurrent pneumonia over the last few months, including involvement of the right middle lobe and left lower lobe and bilateral pleural effusions.

Current labs include: Calcium 10.6 (high); Ionized calcium 5.28 (high); Phosphorus 9.0 (very high); PTH, intact <5 (low) (? nonfunctioning implant); Calcium-Phosphorus product 90 (high).

Radiopharmaceutical:

Tc-99m MDP

Findings:

Bone scan shows classic soft tissue uptake over calves in the region of the patient's plaques consistent with calciphylaxis. No renal uptake is seen due to renal failure and transplant rejection. Marked uptake in the right middle lobe and right pleura inferiorly and posteriorly is present, likely due to chronic inflammation from the patient's pneumonia with superimposed calcium and phosphorus abnormalities.

Tibia/Fibula radiograph shows subtle soft-tissue swelling with superimposed fine reticular calcification, also consistent with calciphylaxis.

Chest radiograph shows bibasilar infiltrates and effusions.

Computed tomography confirms the right middle lobe and left lower lobe infiltrates and effusions. The CT also shows calcification in the right middle lobe, correlating with the uptake on bone scan.

Discussion:

Calciphylaxis is defined as calcification within the subcutaneous soft tissues and vessels. Patients present with dense non-ulcerating plaques in the legs due to subcutaneous calcium deposition. Both lower extremities are usually involved, commonly above the Achilles tendons. Plaques can progress to severe ulcers, usually with eschar formation. The plaques are usually very painful.

The incidence is up to 4% per year in peritoneal dialysis patients, and it is also seen in post-transplant patients. Increasing freqency may be due to use of calcium and vitamin D supplments in these patients. Risk factors include a high calcium-phosphorus product (>70), female sex, peritoneal dialysis, diabetes, hyperparathyroidism, and oral CaCO3 dose.

The bone scan is the test of choice and can be positive in up to 97% of patients, usually demonstrating subcutaneous uptake in areas of plaques. If deep ulcerations are present, there can be loss of subcutaneous calcium containing tissue, and the bone scan will be negative. Conventional radiographs can be negative in 29%; when positive they can range from a subtle, diffuse, fine reticular pattern of calcification to a very coarse reticulo-nodular calcification.

Treatments have included oral prednisone for 3-8 wks, which showed 80% improvement in one study with a ~20% relapse rate in 2-6 months. Parathyroidectomy has been helpful in patients with PTH greater than 4 times normal, after which all cases improved or were cured in one study. Parathyroidectomy may not help patients who already have ulcers. Use of non-calcium containing phosphate binders is useful for prevention. Hyperbaric oxygen is of possible help in trying to reverse ulceration.

Outcome is generally poor, with mortality in patients only with plaques approximately 40% by one year in one study. Mortality with ulcers was reported at 67% by one year in the same study. However, if a patient developed ulcers from plaques, mortality was 89% by one year. Biopsy of the lesions can be dangerous as it can cause non-ulcerating plaques to ulcerate and result in rapid progression of disease and death. Related causes of death included sepsis, weight loss/malnutrition (from analgesics), stopping dialysis. Most patients also have multiple co-morbid conditions which could contribute to mortality.

Reference: Fine and Zacharias, “Calciphylaxis is usually no-ulcerating: Risk factors, outcome and therapy,” Kidney International, Vol 61 (2002), pp. 2210-2217.

Followup:

This patient was followed-up by dermatology for biopsy which revealed dystrophic vascular calcification within small-caliber vessels in the subcutaneous fat, consistent with calciphylaxis. The patient's CaCO3 was stopped to remove a further aggravating source of calcium, but she was continued on Rocaltrol due to possible non-functioning autoimplant. She was started on topical steroids, and her dialysis schedule was adjusted to improve phosphorus levels. The patient is clinically improved.

ACR Codes and Keywords:

References and General Discussion of Bone Scintigraphy (Anatomic field:Vascular and Lymphatic Systems, Category:Metabolic, endocrine, toxic)

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Case number: bs136

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