Endocrine Abstracts

Introduction: Hypercalcemia has been described in patients with granulomatous disorders. Most commonly sarcoidosis (10% of patients) and tuberculosis with three-fold increase in hypercalciuria. It’s due to production of calcidiol from calcitriol in the lung and lymph nodes that is independent of PTH. Main modalities of therapy are low-calcium diet, glucocorticoids, and treatment of the underlying disease.

The Case: A 48-year-old male, referred to endocrine team with hypercalcaemia (calcium 2.96 mmol/l). He had background of Type 2 DM, low mood and hypercholesterolemia. He was under respiratory team for suspected diagnosis of sarcoidosis for several years with suggestive x-ray and CT findings, elevated Serum ACE and recurrent anterior uveitis which has been managed by ophthalmology. No histological proof of sarcoidosis. He was on Metformin 1g bd, Simvastatin 40 mg, Sitagliptin 100 mg od, and Citalopram 40 mg od. His calcium was high at 2.96 mmmol/l on routine investigations and admission was arranged. Investigations revealed impaired renal function with urea 8mmol/l, Cr 118 umol/l, and eGFR of 58 mL/min/1.73m2 (>60mL/min/1.73m2). He expressed symptoms of polyuria and polydipsia, and otherwise had no significant finding on history or examinations. With hydration his Calcium dropped to 2.68 mmmol/l but increased again to 2.92 after 2 days. He was commenced on prednisolone 40 mg. As a result, his calcium level normalized within 10 days

Investigations revealed: Supressed PTH: 1.0(1.6-6.9), Vit D2: <12 nmol/l, Vit D3: 29 nmol/lwith Total vit D of 29 nmol/l. Negative Myeloma screening. ACE was 183 U/l. It was noted that ACE level was high at 156 U/lon August 2020, return to normal at 48 U/lon December 2020, then increased to 183 U/lat this presentation. The patient was discharge home with steroid tapering regimen when his calcium level dropped to 2.65 with follow-up with respiratory team in the OP clinic

Conclusion: Hypercalcemia and hypercalciuria have been described in patients with sarcoidosis and should be borne in mind in differential diagnosis. If undetected, it can cause nephrocalcinosis, renal stones, and renal failure Serum concentrations of vitamin D metabolites, 25-hydroxyvitamin D (calcidiol) and 1,25-dihydroxyvitamin D (calcitriol) should be measured if there is no obvious malignancy and PTH is not elevated. High 25(OH)D is indicative of vitamin D intoxication while increased levels of 1,25-dihydroxyvitamin D may be induced by direct intake of this metabolite, extrarenal production as in granulomatous diseases or lymphoma.