Question

Management of thyrotoxicosis in pregnancy.

Hint:

Early diagnosis and appropriate treatment of thyrotoxicosis in pregnancy are critical for reducing maternal and fetal morbidity and preventing complications like thyroid storm.

Answer 1

Thyrotoxicosis in pregnancy refers to the clinical condition where there is an excess of thyroid hormone in the body, which can adversely affect both the mother and the fetus. The most common cause of thyrotoxicosis in pregnancy is Graves' disease, though it can also result from subacute thyroiditis, toxic multinodular goiter, or other thyroid conditions.
Step 1: Diagnosis of Thyrotoxicosis in Pregnancy:
1. Clinical Features: Symptoms include weight loss, palpitations, tremors, heat intolerance, and increased appetite. Pregnancy-specific symptoms may include hyperemesis gravidarum, as well as an increase in maternal heart rate and blood pressure.
2. Laboratory Tests: Blood tests to measure thyroid function (TSH, Free T4, and Free T3 levels) are essential. In pregnancy, TSH levels are generally lower due to the effects of human chorionic gonadotropin (hCG) on the thyroid gland. Thus, a low TSH with elevated Free T4 and Free T3 suggests thyrotoxicosis.
3. Ultrasound and Radioactive Iodine: A thyroid ultrasound may be used to detect goiter or nodules. Radioactive iodine scans are typically avoided during pregnancy due to their potential teratogenic effects.
Step 2: Treatment of Thyrotoxicosis in Pregnancy:
1. Antithyroid Medications: The first-line treatment involves antithyroid drugs such as propylthiouracil (PTU) or methimazole.
- Propylthiouracil (PTU) is preferred in the first trimester due to its lower risk of teratogenicity, whereas methimazole is more commonly used in the second and third trimesters, as PTU is associated with liver toxicity.
2. Beta-blockers: Beta-blockers such as propranolol can be used to manage symptoms such as tachycardia and tremors, but they should be used cautiously and in conjunction with antithyroid medications.
3. Surgical Intervention: Surgery may be considered in rare cases where antithyroid medications are ineffective or if there is a large goiter causing compression. This is typically avoided in the first trimester due to the risks of anesthesia and potential pregnancy complications.
4. Monitoring and Dose Adjustment: Close monitoring of thyroid function during pregnancy is essential. The dosage of antithyroid medications may need to be adjusted frequently due to changes in thyroid hormone levels during pregnancy.
Step 3: Management of Complications:
1. Thyroid Storm: Thyroid storm is a rare but life-threatening complication of severe thyrotoxicosis, characterized by fever, tachycardia, heart failure, and altered mental status. Immediate treatment with antithyroid drugs, supportive care, and beta-blockers is required.
2. Impact on Fetal Development: Untreated thyrotoxicosis during pregnancy can lead to complications such as preterm labor, low birth weight, and fetal hyperthyroidism. Proper management reduces the risk of these complications.