Endocrine Abstracts

Introduction: Severe hypercalcaemic crisis is a recognized and potentially life threatening presentation of Primary Hyperparathyroidism. Marked bone turnover suggested by elevated ALP predisposes to Hungry Bone Syndrome following parathyroidectomy. This case highlights severe symptomatic hypercalcaemic crisis due to a parathyroid adenoma, with marked skeletal and renal involvement, complicated by Hungry Bone Syndrome post operatively.

Clinical Case: A 48 year old gentleman presented with confusion, nausea, vomiting, dehydration, abdominal pain and proximal muscle weakness. His biochemistry revealed a corrected calcium of 5.93 mmol/l (2.2 – 2.6 mmol/l), PTH of 159.4 pmol/l (1.8 – 6.8 pmol/l), Phosphate of 0.69 mmol/l (0.80 – 1.5 mmol/l), ALP of 406 U/l (30 – 130 U/l), and 25-OH Vitamin D of 17 nmol/l (51 – 374 nmol/l); consistent with severe hypercalcaemia in the setting of Primary Hyperparathyroidism with evidence of high bone turnover, and Vitamin D Deficiency. He had an acute kidney injury with Cr of 294 umol/l (59 – 104 umol/l), multiple right renal calculi up to 4 mm and bilateral nephrocalcinosis on CT KUB imaging, suggesting end-organ damage. CT Neck showed a 1.4 cm x 1.2 cm x 2 cm right inferior parathyroid nodule. Despite medical management with intravenous fluids, bisphosphonate therapy, and Cinacalcet, this patient had refractory symptomatic hypercalcaemia, and considering the severity of the presentation, with end-organ disease involvement, the patient was referred for urgent parathyroidectomy as per NICE guidance, and underwent subsequent explorative surgical excision of the right inferior parathyroid nodule, with histology confirming a parathyroid adenoma. Post operatively, he had prompt PTH normalization to 2.1 pmol/l, and Calcium stabilised to 2.46 mmol/l, confirming removal of the culprit lesion was successful. He soon developed persistent hypocalcaemia, along with persistently elevated ALP, and low phosphate levels, in keeping with Hungry Bone Syndrome. He required close monitoring and management with calcium and Vitamin D supplementation, highlighting the predictive value of raised ALP and high bone turnover pre-operatively.

Conclusion: This case highlights the skeletal and renal manifestations of a hypercalcaemic crisis in Primary Hyperparathyroidism. Elevated ALP is a marker of high bone turnover, and a predictor of the risk of developing Hungry Bone Syndrome following parathyroidectomy. Early surgical intervention, where indicated, can be life saving. Careful anticipatory planning, vigilant post operative monitoring and early recognition and management of post operative hypocalcaemia are crucial to optimize patient outcomes.

References: 1. National Institute for Health and Care Excellence. Hyperparathyroidism (primary): diagnosis, assessment and initial management. NICE guideline NG132. London: NICE; 2019. Available from: https://www.nice.org.uk/guidance/ng132