Endocrine Abstracts

Case History: Mr AT, a 54 year old male was referred by his GP in 2019 with a two year history of raised calcium. He initially sought medical attention for pain radiating from the left buttock to the knee. He had a background of hypertension and pre-diabetes and was on Nifedipine LA 3 mg OD and Furosemide 20 mg OD. He denied headaches, insomnia, concentrating problems, constipation, polyuria and polydipsia. He had no history of fractures nor renal stones. He was a non-smoker and drank little alcohol. There was no family history of raised calcium or kidney stones.

Section 2: Investigations: In 2014, his corrected calcium was normal. Over the next few years his calcium rose to 2.7, 2.84, 2.85 and 2.88 mmol/l in 2017, 2018, 2019 and 2020 respectively. Correspondingly PTH was elevated at 156 and 192 ng/l in 2019 and 2020. Vitamin D was normal at 52, 62 and 56 nmol/l in 2018, 2019 and 2020 respectively. The first calculated urine calcium: creatinine excretion ratio was 0.0028 in June 2019. Renal ultrasound in 2019 was normal. DEXA scan showed Osteoporosis at the lumbar spine with a T score of –3.1. He had an MRI spine 2019 prior to referral showed multilevel arthritis. NM Parathyroid showed a suspected right inferior parathyroid adenoma. Ultrasound of parathyroid was discordantand did not reveal an adenoma. He was referred for parathyroid surgery.

Section 3: Results and treatment: He underwent four gland exploration and the right inferior pararathyroid gland was excised in June 2020. Histology of the excised gland showed a normal parathyroid. Post surgery his calcium levels were not corrected and remains elevated. Genetic analysis in December 2020 was negative for AP2S1, CASR and GNA11 gene variants. His bisphosphonate were stopped recently and localising scans were requested and if required Choline PET scan and 24 hour urine sample for calcium: creatinine clearance and a parallel blood test same day(sample in lab)

Section 4: Conclusions and points for discussion: Persistent hypercalcaemia post-surgery for suspected primary hyperparathyroidism. 1. Is this primary hyperparathyroidism or autoantibody associated FHH? 2. Does low Ca: Cr excretion ratio make hyperparathyroidism unlikely? 3. What further tests can be carried out to determine the cause of raised calcium and PTH? What is role functional imaging in this scenario 4. How common is autoantibody associated FHH?