Endocrine Abstracts

Introduction: Worsening of hypercalcaemia is common during intercurrent illnesses in patients with primary hyperparathyroidism. Here, we present a patient with primary hyperparathyroidism developing an acute, severe exacerbation with the highest calcium level we have seen.

Case: A 66-year-old female was referred to the Endocrinology clinic by her GP with an incidental finding of hypercalcaemia on routine blood tests (adjusted calcium 2.61nmol/l (NR 2.12-2.51), phosphate 0.92nmol/l (NR 0.8-1.5), PTH 12.82pmol/l (NR 1.95-8.49), creatinine 73umol/l (NR 60-120)). She was asymptomatic with no evidence of end organ damage at the time so conservative management was pursued with a request for DEXA (showed osteoporosis) and urinary calcium:creatinine ratio (0.15mmol/mmol creatinine (NR0-0.59)). There was no family history of calcium disorders. Whilst awaiting follow-up, she had an acute admission with nausea, vomiting, drowsiness, polydipsia and constipation and serum calcium was profoundly elevated at 5.66mmol/l, phosphate 1.32nmol/l, creatinine 239umol/l, PTH 187.98pmol/l. This hypercalcaemia was consistent on repeat testing making a lab error unlikely. She was treated with IV fluids cautiously due to a history of heart failure. With this, the calcium gradually fell to 2.32nmol/l and has remained stable at 2.55-2.8nmol/l since, but creatinine did not improve and she has now developed CKD5. Ultrasound and SPECT both revealed a culprit parathyroid lesion but her journey has been complicated by calculus cholecystitis and exacerbations of heart failure and she has been deemed high risk for an anaesthetic. She is being prepared for dialysis.

Learning points: • Adjusted calcium level higher than 5.66mmol/l in primary hyperparathyroidism could not be found in the literature. • Parathyroid malignancy must be a concern in sudden and profound hypercalcaemia but is difficult to diagnose without evidence of metastatic disease. • Irreversible renal impairment can occur with profound hypercalcaemia in primary hyperparathyroidism, especially with coinciding risk factors such as hypertension, diabetes and diuretic therapy.