ODP099 Hyperparathyroidism Causing life Threatening Hypercalcaemia in Pregnancy

31 year old woman (G2P0) 14 weeks pregnant was admitted for investigation of acute renal failure. Her creatinine was 171umol/L (normal: 45-84umol/L). Prior to her admission, patient was under investigation for a small for gestational age (SGA) baby, and had amniocentesis for suspected triplody. However, the result was normal. On admission, the patient gave a history of severe nausea and vomiting that started at 6 weeks gestation. There was also a history of constipation, lethargy and weakness. Admission blood tests showed a severe primary hyperparathyroidisim with corrected calcium level of 4.1mmol/L (normal: 2.2-2.6mmol/L), PTH=36.9 (1.6-6.9pmol/L), and thyrotoxicosis (TSH<0. 01, FT4=32.2 (12-22pmol/L). Her 24hour Urinary calcium was raised at 19.1mmol (normal: 2.5-7.5mmol/24hours) and 25 OH Vitamin D3 was 64nmol/L (Vitamin D >50 considered replete). On examination, there was a palpable nodule in the region of the left thyroid lobe. The patient was treated with 6 hourly IV fluids and carbimazole 20mg OD. Ultrasound of the neck showed a heterogenous vascularised lesion along the inferior aspect of the left thyroid lobe, 21×22×26mm in size. The lesion was thought to be a large atypical parathyroid adenoma (APA), although a parathyroid carcinoma could not be ruled out on ultrasound. Meanwhile, the patient remained hypercalcaemic with corrected calcium of 3.2mmol/L, despite aggressive IV fluids and cinacalcet 60mg BD. Her renal function improved, creatinine=110umol/L. The patient was also noted to be hypertensive, with BP ranging between 150/80 to 160/110mmHg. She was still having GI symptoms, namely retching and vomiting. In light of biochemical and clinical findings, parathyroidectomy was done in the second trimester of pregnancy. The surgery was uneventful. Cinacalcet was stopped and Ad Calcium was normal within 48hours of surgery. Ad cal=2.58, PTH low at 0.7. Patient was discharged after parathyroidectomy. The histology report was in keeping with atypical parathyroid adenoma (APA). Ultimately, our patient had a spontaneous vertex delivery of a male infant at 35+2. The baby was SGA and spent time in SCBU with fits and hypocalcaemia (Ad Cal=1.8). Baby was seen by neonatologist post discharge, and has normal development at the time of writing. Presentation: No date and time listed