Endocrine Abstracts

Sarcoidosis is a rare multisystem granulomatous disease that most commonly affects the lungs and skin, and can also affect eyes and lymph glands. We describe an unusual case of sarcoidosis presenting with hypercalcemia, causing diagnostic challenges. A 5year old boy was incidentally found to have asymptomatic hypercalcaemia during a routine clinic review for failure to thrive. Apart from a recent Influenza A infection, when he was found to have normal calcium levels and severe vitamin D deficiency (10.2 nmol/l), he was well. He was started on vitamin D treatment (6000 units daily). Blood tests 3 months later showed hypercalcaemia (3.52 mmol/l), with renal impairment (creatinine 65 micromol/l), low-normal PTH (1.6 pmol/l), normal vitamin D (152 nmol/l), phosphate (1.03 mmol/l) and magnesium (0.84 mmol/l). He had resistant hypercalcaemia despite hyperhydration and furosemide, and required three doses of calcitonin, and two doses of pamidronate, to normalise his calcium levels. Parathyroid USS showed bilateral hypoechoic lesions. A whole-body nuclear medicine scan showed no parathyroid or bony foci. A renal USS showed bilateral echogenic kidneys with no hydronephrosis or nephrocalcinosis. Tuberculosis and syphilis screens were negative. In view of persistent conjunctivitis, he was referred to ophthalmology. They found pan-uveitis with choroid scars, which together with high-normal serum angiotensin converting enzyme (ACE 108 U/l; range 29–112 U/l) was suspicious of sarcoidosis. Further blood tests showed his 1,25-dihydroxyvitamin D level was raised (154 pmol/l; range 55–139 pmol/l), with normal 25-hydroxyvitamin D (93.5 nmol/l). He was given a clinical diagnosis of sarcoidosis in view of pan-uveitis, choroidal scars and raised ACE (185 U/l), with hypercalcemia likely secondary to raised 1,25-dihydroxyvitamin D. At 1 year, the sarcoidal changes in his eyes have improved. He remains well, with no musculoskeletal or respiratory symptoms, headache, hair loss, or mouth ulcers. His calcium and renal function remain normal. It is unclear if his initial renal impairment was secondary to hypercalcaemia or sarcoidosis. There are numerous case reports of children with sarcoidosis presenting with hypercalcaemia, secondary to increased 1-alpha-hydroxylase activity in granulomas, leading to increased 1,25-dihydroxyvitamin D, requiring treatment with steroids/bisphosphonates. Sarcoidosis should therefore remain in the differential of unexplained hypercalcaemia, especially if associated with additional skin, eye, renal or respiratory features.