Endocrine Abstracts

Introduction: The combination of hypokalemia and hypercalcaemia is uncommon but potentially lethal. In primary hyperparthyroidism hypokalaemia most commonly occurs due to incomplete distal renal tubular acidosis. We present the first case of simultaneous primary hyperparathyroidism with Gitelman’s syndrome resulting in profound electrolyte imbalance.

Case: A 48-year old man, referred with hypokalaemia (2.5 mmol/l) presented with a short history of extreme fatigue, myalgia, nausea and constipation. His adjusted serum calcium was raised (2.84 mmol/l). Patient was otherwise fit and well. He denied any regular medications or liquorice intake. He had no contributory medical family history and never smoked. There was nothing to suggest underlying tuberculosis, sarcoidosis or malignancy. He had normal stature and was normotensive. There was no stigmata of hypercortisolism or lymphadenopathy. Cardiovascular, respiratory and abdominal examinations were all normal. Subsequent bone profile check noted adjusted serum calcium rise to 4.01 mmol/l and prompted urgent administration of bisphosphonates.

Further investigations confirmed diagnosis of primary hyperparathyroidism secondary to large single parathyroid adenoma. Following parathyroidectomy patient’s bone profile normalised, hypokalaemia however, persisted. It was accompanied by hypomagnesaemia and metabolic alkalosis. Battery of further endocrine investigations including random glucose (5.1 mmol/l), HbA1c (5.4%), thyroid, anterior pituitary, overnight dexamethasone suppression test, calcium/creatinine urine excretion ratio, fasting gut polypeptides and MEN genotyping all proved normal. Chest and abdominal radiology were also normal. Notably, significant hyper-reninaemic hyperaldosteronism was discovered and confirmed twice on both supine and ambulatory sampling. Diagnosis of Gitelman’s syndrome was made and patient was commenced on Amiloride with a desirable effect.

Conclusion: It is known that primary hyperparathyroidism can cause hypokalaemia, but we report this rare combination of Gitelman’s syndrome in an otherwise healthy patient.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.