Endocrine Abstracts

Disorders of calcium metabolism are common in Sarcoidosis. The frequency of hypercalciuria and hypercalcaemia has been reported as 30–50% and 10–20% respectively. The underlying mechanism is enhanced PTH independent extra-renal production of 1,25-Dihydroxy Vitamin D (Calcitriol) which increase absorption of Calcium from the gut causing hypercalcaemia.

A 79 year old lady was admitted with fever, cough and night sweats and was treated for pneumonia. Initial investigations showed raised WBC, acute kidney injury (on background of CKD) and anaemia. As a part of geriatric assessment, the following results were obtained: severely low 25-OH vitamin D level (14 nmol/L), normal Calcium (2.42 mmol/L) and normal PTH (2.7 pmol/L). She received only one dose of 25,000IU Vitamin D (as part of weekly replacement regime). Two days later, Calcium was 2.69 and AKI slightly worsened. Combination of AKI, anaemia and hypercalcaemia triggered investigations for multiple myeloma which came back negative. Over the next few days, there was further deterioration in the AKI and the repeat Calcium level went sharply up to 4.0mmol/L despite fluid resuscitation. Digging into the past medical history, this lady had a previous history of active sarcoidosis 43 years ago requiring high dose steroids for a few months.

Further investigations showed elevated serum ACE level (88, Normal 8–50). HRCT did not show any changes of pulmonary sarcoidosis or hilar lymphadenopathy. Repeat 25-OH Vitamin D was 26, PTH was suppressed (1.3) and 1,25 Dihydroxy Vitamin D level is still awaited. She was empirically treated with high dose Prednisolone and the Calcium level came down to normal range over the next 2 weeks.

This is an interesting case of acute severe hypercalcaemia where the cause is not entirely clear. We think that the likely cause of severe hypercalcaemia in this lady is extra-renal activation (1-alpha hydroxylation) of exogenous 25-OH vitamin D3 secondary to sarcoidosis, though we do not have convincing evidence for relapse of acute sarcoidosis.