A 52-year-old female presented to hospital with a two day history of emesis and poor oral intake, on a background of six weeks of nausea, fatigue, two kilograms of weight loss and irregular vaginal bleeding. Thyroid function tests (TFTs) identified overt hyperthyroidism (TSH <0.01 mU/L [0.15-5.09 mU/L], fT4 47.2 pmol/L [9-19 pmol/L]) and concurrent βhCG testing was positive (73,036 U/L). Pelvic ultrasound and CT scan identified a 10 x 12 x 5 cm (297 cc) intrauterine heterogenous multicystic structure without definable foetal pole or yolk sac. Thyroid auto-antibody testing was negative, and a diagnosis of hyperthyroidism secondary to gestational trophoblastic disease (GTD) was established.
Hysterectomy with bilateral salpingectomy was determined to be the most suitable surgical management based on patient age, treatment preference and disease burden. Perioperatively, Carbimazole 30 mg and prednisolone 25 mg daily were utilised for one week to reduce degree of hyperthyroidism. Immediate preoperative TFTs showed a slight reduction in hyperthyroidism (TSH 0.01 mU/L [0.15-5.09mU/L], fT4 28 pmol/L [9-19pmol/L], fT3 8.6 pmol/L [2.5-6pmol/L]).
Hydrocortisone 50 mg QID and propranolol 40 mg daily were commenced on the day of surgery. Surgical resection proceeded uneventfully and histology confirmed non-invasive complete hydatiform mole. Over the following 10 weeks, normalisation of βhCG was associated with rapid resolution of hyperthyroidism without need for further pharmacotherapy.
Hyperthyroidism is a rare complication of GTD and is clinically apparent in 4-10% of cases (1). It develops due to the homology between βhCG and TSH with subsequent stimulation of the TSH receptor. Currently, no standardised guidelines exist for peri-operative management of hyperthyroidism in GTD, despite the known risk and mortality risk of hyperthyroidism in the peri-operative setting (2, 3). This case highlights the use of carbimazole, glucocorticoids and beta-blockers to successfully mitigate perioperative risk in a 52-year-old lady with overt hyperthyroidism and GTD.