Endocrine Abstracts

A 27-year old Caucasian woman was referred to the Endocrine Bone Clinic after investigations for general malaise revealed hypercalaemia and elevated parathyroid hormone levels. She had no history of constipation, abdominal pain, bone pain, or other related symptoms. She had no history of renal stones or fractures and no change in weight. Her past medical history included asthma and she took a salbutamol inhaler as required. She had no family history of endocrine pathology. General examination was unremarkable. Her adjusted calcium level was 3.01mmol/l (RR2.2-2.6), phosphate level was 0.61mmol/l (RR0.8-1.5), parathyroid hormone level was elevated at 14 pmol/l(RR1.6-7.2) with low vitamin D levels 18.9nmol/l (RR70-150). She had normal renal function and normal thyroid function. 24 hour urinary collection was taken which excluded familial hypocalciuric hypercalcaemia (24h urine calcium 8.49mmol/24h (RR2.5-7.5), urine calcium:creatinine ratio 0.03). She had a normal pituitary profile, normal gut hormone profile and genetics did not identify any familial cause (genes tested: CASR, CDC73, CDKN1A/1B/2B/2C, MEN1, RET). An initial Sestamibi scan did not localise any clear adenoma. A neck ultrasound revealed a 14mm lesion bulging out of the posterior aspect of the right thyroid lobe. Given the uncertainty as to the origin, an FNA was performed with non-diagnostic histology but a PTH level of 861 pmol/l. A renal ultrasound revealed bilateral unobstructing renal calculi, with the largest stone measuring 6.2mm. A bone densitometry scan showed normal bone density including at the distal radius. She was referred for parathyroid surgery and was advised to increase her fluid intake. Due to her work as a delivery driver, she found it difficult to adhere to this due to lack of toilet facilities. Her malaise continued with development of nausea and constipation. Therefore, cinacalcet was introduced while awaiting surgery, with symptomatic relief. At parathyroidectomy, an abnormal right superior parathyroid was excised with subsequent normalisation of calcium and parathyroid hormone levels and symptomatic resolution. The histology revealed hypercellular parathyroid tissue and so she continues under follow-up. She remains normocalcaemic and her previous renal stones are no longer present on imaging.