Case study:
Mrs AT is a 49-year-old Sudanese G8P7 lady who was diagnosed with thyroid storm after presenting with symptomatic heart failure, severe hypertension, tachycardia, nausea and vomiting. Her medical history was significant for obesity and non-pharmacologically managed hypertension. Investigations revealed highly elevated βhCG levels >239,000IU/L, prompting a pelvic ultrasound that confirmed presence of hydatidiform molar pregnancy. She was found to be newly thyrotoxic with thyroid stimulating hormone (TSH) <0.03mIU/L (0.38–5.1mIU/L), free T4 of 60.4pmol/L (8.0– 16.5pmol/L) and T3 of 20.2pmol/L (3.3–6.8pmol/L). TSH receptor antibodies were negative for Graves’ disease. A transthoracic echocardiogram showed severe pulmonary hypertension with estimated pulmonary artery systolic pressure >60mmHg and moderate-severe tricuspid regurgitation. She was managed for thyroid storm with propylthiouracil (PTU), intravenous hydrocortisone, Lugol’s iodine solution and high-dose beta blockers, with concerns surrounding high peri-operative risk. Evacuation of the molar pregnancy was performed via dilation and curettage. Pathology confirmed complete hydatidiform mole. Post-operatively, βhCG levels declined rapidly with associated improvement in thyroid function. However, Mrs AT remained thyrotoxic requiring ongoing management with PTU post-operatively.
Discussion:
Molar pregnancy typically presents with vaginal bleeding, excessive uterine enlargement and hyperemesis gravidarum. Thyroid storm is a rare presentation for molar pregnancy, but early identification and treatment can significantly improve morbidity and mortality.
Hyperthyroidism in molar pregnancy is attributed to highly elevated βhCG levels, which increase free T3 and T4 through stimulation of the TSH receptor due to structural similarity between βhCG and TSH.
Following molar pregnancy evacuation, it can take months for βhCG levels to become undetectable and thyroid function to normalise. Pulmonary hypertension can be reversible with treatment of the underlying thyroid disease. Therefore, we anticipate resolution of pulmonary hypertension and heart failure in Mrs AT following normalisation of her thyroid function.
Conclusion:
Molar pregnancy should be considered in women of reproductive age who present with thyrotoxicosis.