REPEAT BONE SCAN AS A METHOD OF MONITORING RESPONSE TO SODIUM THIOSULFATE IN CALCIPHYLAXIS – A CASE REPORT
Dr Evelyn Perry1,2, Dr James Burgess1, Dr Hnin Hnin Aye1, Dr Rachel Elliott1, Dr Lee Skeat1,2, Dr Geoff Kirkland1, Dr Steven Yew1, Professor Matthew Jose1,2, Dr Richard Yu1
1Royal Hobart Hospital, Hobart, Australia, 2University of Tasmania, Hobart, Australia
Background: Calciphylaxis, or calcific uremic arteriolopathy, is a rare condition which can present diagnostic and therapeutic challenges for patient and clinician. It is associated with high morbidity and mortality. Technetium-99m methyldiphosphonate (Tc-99m MDP) bone scans has been reported to be a promising tool in the early diagnosis of calciphylaxis with reported high sensitivity (generally in excess of 90%). However, its role in monitoring treatment response has not been confirmed. We describe a case where successive Tc-99m MDP bone scans were used to first diagnose calciphylaxis and then to monitor treatment response.
Case Report: A 61-year-old Aboriginal woman on haemodialysis presented with induration and ulceration involving the right anterior triangle of her neck over the site of a recently removed central venous catheter. CT neck with contrast showed inflammatory stranding and swelling of subcutaneous fat in the affected region. Tc-99m MDP bone scan demonstrated intense tracer activity within the neck mass in keeping with ectopic calcification and strongly suggesting calciphylaxis. A biopsy was not performed. Her calcium and phosphate indices were optimised, and she was commenced on sodium thiosulfate 25g post-dialysis. Twelve weeks later, a repeat Tc-99m MDP bone scan showed a dramatic reduction in tracer uptake within the right side of the neck, correlating clinically with marked improvement in her indurated neck mass and resolution of previous overlying necrotic ulceration.
Conclusions: Tc-99m MDP bone scan has utility not only in the diagnosis of Calciphylaxis but also in monitoring response to therapy. We postulate that the dramatic improvement in ectopic calcification on Tc-99m MDP bone scan alludes to the importance of calcium chelation as a crucial mechanism of action in the therapeutic effects of sodium thiosulphate.
Biography:
Eve is a first-year renal advanced trainee working at the Royal Hobart Hospital. She has a professional interest in general nephrology, obstetric medicine and medical education. In her spare time, Eve enjoys hiking and seeing live music.