Bone Abstracts

Background: We present a case of unusual delayed multi-systemic reaction, following treatment with Pamidronate. The reaction, resembling rhabdomyolysis, requiring intensive care support, has not been reported previously to our knowledge.

Presenting problem: An 11 month old boy with severe osteogenesis imperfecta (OI) presented with hyperpyrexia and respiratory distress 10 days after his fifth cycle of Pamidronate. He had significant derangement of his biochemical parameters (see table) including a positive urine myoglobin. His respiratory distress was out of proportion to the chest radiograph changes. BiPAP was required for ventilatory support.

Clinical management: He was initially treated as presumed sepsis. However, there were no significant positive microbiology cultures and investigations for Haemophagocytic lymphocytosis were negative. He was managed with supportive treatment and gradually improved. He subsequently developed decreased head movement, stiffness of limbs, poor interaction with carers and an anxious look. He had a normal CT head and cervical spine raising the possibility of continuing muscle and bone pain. He showed an excellent response to morphine.

Discussion: Serious adverse reactions have been reported with bisphosphonate use including renal failure after several cycles, severe muscle and bone pain, dermatomyositis and rhabdomyolysis in adults^1-3. Our patient may have developed rhabdomyolysis following Pamidronate treatment, which has not been reported previously in children. He was extensively investigated to exclude other possibilities and made a full recovery with only supportive management.

Disclosure: The authors declared no competing interests.

References:
1. D Aguiar Bujanda et al. “Assessment of renal toxicity and osteonecrosis of the jaws in patients receiving zoledronic acid for bone metastasis.” Ann of Onc (2006) 18: 3; 556-560.

2. Tong PL et al. “Drug induced myositis after Zoledronic acid”. Aust J of Derm (2012) 53: 4; e735.

3. Schaefer MW et al. Rhabdomyolysis associated with intravenous zoledronic acid infusion for the treatment of postmenopausal osteoporosis [abstract no. P2-205]. Endocr Rev 2010 Jun; 31 (3 Suppl. 1).