Oral sodium thiosulfate solution as a secondary preventive treatment for calciphylaxis in dialysis patients

MUSSO CG

Saudi J Kidney Dis Transpl.

Medknow

Año: 2008

1319-2442

To the Editor, Calciphylaxis is a severe complication in chronic dialysis patients which consists of an inflammation of the skin with edema, erhythema and pain that may evolve to extensive superficial necrosis of the skin resulting in ulceration and scar formation overlying a panniculitis. Such lesions are most often located on the abdomen, buttocks, thighs, and/or legs. Diagnosis is confirmed when calcification of the middle layer of the dermis small arteries is documented in the affected areas.1,2 There are recent reports regarding the potential therapeutic benefits of intravenous sodium thiosulfate (37.5-75 grams/week) in calciphylaxis. This substance is an inorganic pentahydrated salt which is absorbed from the digestive tract. In addition, it is distributed to the whole extracellular fluid when administered intravenously, and is quickly excreted in the urine. Except for the osmotic alterations, that can cause diarrhea, sodium thiosulfate is not toxic. It has also been described as a therapeutic alternative in cyanide intoxication (intravenous), and calcium urolithiasis (oral).3-5 We would like to share our experience of using oral sodium thiosulfate (7.5 grams/week) as a secondary preventive treatment for calciphylaxis. Our patient was a 59 year-old woman on maintenance hemodialysis with other comorbidities including diabetes mellitus (type II), arterial hypertension, obesity, and parathyroid hormone surgery due to hyperparathyroidism. She developed severe abdominal and inguinal calciphylaxis ulcers that healed with intravenous sodium thiosulfate (37.5 grams/week) after each hemodialysis session for a period of eleven months. Even after her ulcers completely healed, due to the multiple risk factors, we decided to continue sodium thiosulfate treatment as an oral preparation of 2 M (molar) solution: 74.4 grams in free water (150 cc). Since this was a secondary preventive measure, we decided to use half of the intravenous dose: 2.6 grams/day. However, the patient developed diarrhea and the dose was reduced to 2.6 grams after each hemodialysis session (thrice a week). She received this secondary preventive treatment for a lapse of one year, during she maintained serum calcium level: 8.3 mg/dL (range: 7.3-9 mg/dL), serum phosphorus: 5.4 mg/dL (range 4-6.7 mg/dL), calcium-phosphorus product (45 mg/dL), and serum parathyroid hormone: 365 pg/dL, while she was taking calcium acetate (8 grams/day) as phosphorus binder treatment. During this period she did not develop any new calciphylaxis lesions or sodium thiosulfate adverse effects. Furthermore, at one occasion when she stopped the treatment for a month due to unavailability of the drug, she started feeling the characteristic intradialysis pain on her abdominal calciphylaxis scars, which disappeared after restarting oral sodium thiosulphate.6-9 We believe that oral sodium thiosulfate could be a Saudi Journal of Kidney Diseases and Transplantation [Downloaded free from http://www.sjkdt.org on Friday, May 5, 2017, IP: 10.0.10.36] potential preventive treatment for calciphylaxis in dialysis patients