New Discoveries Provide Insights Into Calciphylaxis
It is unclear to physicians why some patients develop calciphylaxis while others do not.
Perhaps nothing is more frustrating to clinicians than not being able to ease patients' suffering or stave off death from a debilitating medical condition. No medical subspecialty faces this dilemma more than nephrologists. They care for more than 450,000 end-stage renal disease patients on chronic dialysis in the United States, arguably one of the most clinically challenging groups of patients in medicine. These patients have mortality rates of 20% or more per year. On top of the multiple comorbidities from which most dialysis patients suffer, a few develop a painful and often-fatal condition for which no generally accepted disease-altering treatment exists: calciphylaxis, also referred to as calcific uremic arteriolopathy.
It is not precisely clear how calciphylaxis develops and why it occurs in some patients and not others. Previous studies have found a link between warfarin use and calciphylaxis, but these studies were too small to allow identification of other potential risk factors. In this issue, we report on the largest study by far to examine risk factors for calciphylaxis. The study, led by Sagar U. Nigwekar, MD, MMSc, of Harvard University Medical School and Massachusetts General Hospital in Boston, included 1,030 hemodialysis (HD) patients with newly diagnosed calciphylaxis.
In addition to warfarin use, diabetes mellitus, skin trauma, higher body mass index, and use of nutritional vitamin D and cinacalcet at the time of HD initiation were independently associated with an increased risk of calciphylaxis, Dr. Nigwekar and his colleagues reported in the Journal of the American Society of Nephrology. The identification of additional risk factors is a noteworthy advance that could better enable researchers to develop strategies to prevent and treat calciphylaxis.
In a separate report published recently in the Journal of Dermatological Treatment, researchers reported on a series of 8 calciphylaxis patients treated with sodium thiosulfate, a drug indicated for cyanide toxicity, at University Hospital of Leuven in Belgium. Four patients achieved complete healing of skin lesions, 2 had stabilization of disease while experiencing pain relief. The remaining 2 had progression of the disease. Four patients eventually died due to calciphylaxis-related causes.
Anecdotally, Dr. Nigwekar said he has had some success using sodium thiosulfate to treat calciphylaxis; however, more rigorous studies are needed to ascertain its efficacy.
Calciphylaxis is quite rare, but it is likely that many nephrologists will encounter at least 1 case during their careers. With the progress being made in the understanding of the condition, nephrologists in the not-too-distant future may well have something in their armamentarium to offer their patients with calciphylaxis.