RESUMEN
OBJECTIVES: Bisphosphonates are used in childhood osteoporosis but can cause an acute phase reaction (APR) and hypocalcemia. We present a child with cardiac thrombosis following zoledronate, a previously unreported complication. CASE PRESENTATION: An 11-year-old with Duchenne muscular dystrophy and steroid-induced osteoporosis presented 48 h after first zoledronate infusion with fever, tachycardia, tachypnoea and hypoglycaemia. This was managed as acute adrenal crisis and possible sepsis. He also had hypocalcemia, hypophosphatemia, hyponatraemia and hypokalaemia. Echocardiography performed due to persistent chest pain and tachycardia revealed a left ventricular thrombus. CONCLUSIONS: Potential causes for intracardiac thrombosis in this patient include ventricular dysfunction due to acute adrenal crisis or electrolyte disturbance, and hypercoagulability due to the APR. Echocardiography should be considered in children with acute cardiovascular compromise following zoledronate. Stress-dose steroids to cover the APR and a reduced starting dose of zoledronate might have reduced the risk of this complication.