Endocrine Abstracts

Background: Duchenne muscular dystrophy (DMD) is a progressive muscle disorder characterised by muscle wasting and weakness. It is often associated with intracellular hypercalcaemia in dystrophin deficient muscle leading to disease progression. We present a comprehensive case report of extracellular hypercalcaemia in a DMD patient, a rare complication, emphasising the interplay of iatrogenic factors, immobilisation, and therapeutic approaches.

Case Presentation: A 28-year-old male with DMD, wheelchair-bound, on continuous CPAP with a background of severe cardiomyopathy, presented with fatigue, anorexia, and constipation. Laboratory assessment revealed markedly elevated serum calcium levels (3.78 mmol/l), normal vitamin D levels and suppressed parathyroid hormone (PTH) levels. A malignancy screening was done including CT of thorax and abdomen which showed no lesions, and a myeloma screening was negative. Thyroid function tests and cortisol were normal, ALP was within range ruling out primary bone disease. An in-depth examination of the patient’s medical history uncovered that he was on multiple doses of daily nutritional supplement milkshakes that provided excessive amounts of calcium- 338% of reference nutrient intake (RNI). This was combined with prolonged immobilisation due to respiratory insufficiency.

Management and Outcome: The patient was diagnosed with iatrogenic hypercalcaemia induced by a combination of inappropriate supplementation and immobilisation-related factors. Intravenous fluids and furosemide were administered to lower calcium levels under close monitoring to avoid fluid overload. A dietician was consulted, and his nutritional supplements were optimised to lower calcium intake whilst still meeting energy and protein requirements. Meticulous monitoring of electrolytes, renal function, and bone health was initiated. Gradual normalisation of calcium levels and clinical improvement occurred over several weeks.

Discussion: This case underscores the need for tailored management in DMD patients, recognising the intricate relationship between iatrogenic factors, immobilisation, and hypercalcaemia. Awareness of the potential risks posed by unsupervised supplementation and prolonged inactivity is vital. Monitoring of calcium, vitamin D, and PTH levels is pivotal in preventing hypercalcaemia-related complications, which could exacerbate muscular weakness and impact overall health.

Conclusion: Iatrogenic hypercalcaemia demands consideration when evaluating DMD patients with unexplained symptoms, especially in the presence of inappropriate supplementation and immobilisation. A comprehensive approach encompassing thorough history-taking, judicious prescribing practices, and vigilant monitoring is indispensable to prevent and manage hypercalcaemia. Healthcare practitioners must be attuned to the complex interplay between these factors, ensuring optimal care for DMD patients while minimising potential adverse outcomes.