Calciphylaxis: no therapeutic concepts for a poorly understood syndrome?

Calciphylaxis is a very uncommon and severe disease which mainly appears in patients with chronic renal insufficiency. It presents with ischemia and necrosis of the skin, subcutaneous adipose tissue, muscles and rarely viscera. The pathogenetic mechanisms inducing calciphylaxis are for the most part unknown. The mortality rate of 80% in the first year is very high. Patients experience marked pain, recurrent infections and the constant risk of secondary sepsis. Even multidisciplinary therapeutic strategies are limited, although there are recent case reports providing promising new therapeutic options including sodium thiosulfate and cinacalcet. This review summarizes the important aspects of diagnosis, pathogenesis, prevention and the possible therapeutic strategies of this intriguing, rare and often fatal disease.

Pathogenesis and treatment of renal osteodystrophy

Renal osteodystrophy is the term used to describe the many different patterns of the skeletal abnormalities that occur in patients with chronic kidney disease. The main two conditions are osteitis fibrosa, characterized by high bone turnover, increased osteoclastic and osteoblastic activity, and high levels of circulating parathyroid hormone (PTH) and adynamic bone disease characterized by low bone turnover and low levels of circulating PTH. Retention of phosphorus, decreased levels of calcitriol in blood, decreased levels of serum ionized calcium, reduced numbers of vitamin D receptors and calcium sensors in the parathyroid gland, and skeletal resistance to the calcemic action of PTH play a major role in the development of renal osteodystrophy. This review will describe the current approach for the treatment of renal osteodystrophy.

Calciphylaxis: emerging concepts in prevention, diagnosis, and treatment

Calciphylaxis is a small vessel vasculopathy involving mural calcification with intimal proliferation, fibrosis, and thrombosis. This syndrome occurs predominantly in individuals with renal failure and results in ischemia and necrosis of skin, subcutaneous fat, visceral organs, and skeletal muscle. The syndrome causes significant morbidity in the form of infection, organ failure, and pain. Mortality rates are high. In individuals with renal failure, risk factors for the development of calciphylaxis include female sex, Caucasian race, obesity, and diabetes mellitus. Many cases occur within the first year of dialysis treatment. Several recent reports demonstrate that prolonged hyperphosphatemia and/or elevated calcium x phosphorus products are associated with the syndrome. Protein malnutrition increases the likelihood of calciphylaxis, as does warfarin use and hypercoagulable states, such as protein C and/or protein S deficiency. Recent advances in diagnostic tools and therapeutic strategies have helped in the management of patients with calciphylaxis.

Calciphylaxis in two patients with end-stage renal disease

Fatal calciphylaxis (CPX) occurred in two 71-year-old females both requiring haemodialysis for end-stage renal disease. Case 2 also had an associated follicular lymphoplasmocytoid lymphoma. Although laboratory tests disclosed normal coagulation parameters, this woman had a striking cutaneous histological picture of vessel thrombosis and finally died of disseminated intravascular coagulation. CPX is a rare but potentially life-threatening complication of renal failure. The clinical picture is primarily characterized by livedoid purpura with subsequent cutaneous ischaemia and painful ulcerations. Cutaneous ischaemic phenomena are sustained by a progressive process of vascular calcification and thrombosis involving small to medium size arteries of the dermis and subcutis. Although not yet clearly explained, the pathogenetic role of a predisposing hypercoagulability state is currently the most frequently considered hypothesis.