Endocrine Abstracts

A 26-year-old Caucasian female presented at 14 weeks gestation with a 6-week history of lethargy, nausea and vomiting during her first pregnancy. Her adjusted Calcium was 4.12 mmol/l and parathyroid hormone (PTH) 26 pmol/l, consistent with possible primary hyperparathyroidism. She was previously well apart from occasional migraines. There was no known history of familial hypercalcaemia or MEN. Other biochemistry results revealed hypokalaemia of 3.2 mmol/l, low vitamin D at 16 nmol/l, raised 24-hour urine calcium at 8.11 mmol/24 hr, and a transient thyrotoxicosis, associated with hyperemesis gravidarum which later resolved. MEN screen negative. She was treated with intravenous isotonic saline and electrolytes deficiencies were replaced. She was also commenced on a maintenance dose of vitamin D with colecalciferol 400 units once daily. An ultrasound neck showed no evidence of parathyroid adenoma and a sestamibi nuclear medicine scan was contraindicated due to pregnancy. MRI neck was deemed not sufficiently sensitive to identify a small parathyroid adenoma. Her calcium level normalised prior to discharge. She was readmitted 3 weeks later with symptoms of generally unwell, nausea and vomiting, with an adjusted calcium of 3.41 mmol/l. Her calcium levels responded well to intravenous saline rehydration, and as she was now in her second trimester, she was referred to the tertiary centre hospital for exploratory neck surgery. This had demonstrated four normal parathyroid glands with no evidence of an adenoma. Working diagnosis was now towards an ectopic fifth parathyroid gland or mediastinal adenoma or possibly a placental-driven cause. Meanwhile, patient had struggled with recurrence of symptoms and persistent hypercalcaemia when not receiving aggressive intravenous rehydration. Following discussions with the patient and the multidisciplinary team across both tertiary and local hospitals, she was started on cinacalcet 30 mg twice daily. Her adjusted calcium had improved to 2.62 mmol/l. She later had spontaneous rupture of membranes and went into premature labour at 24+5 weeks gestation, delivering a live baby boy who needed care in the neonatal unit, in view of prematurity. Further investigations are underway, and placental histology is awaited. This case highlights the challenges of diagnosing as well as adequately treating hypercalcaemia in pregnancy. Hypercalcaemia is rare in pregnancy, and symptoms can be nonspecific and mimic those in early pregnancy. Therefore, it is important to have a low threshold in screening and early involvement of the multidisciplinary team with patient and her partner, in order to mitigate harm to both mother and fetus.