Differential Diagnosis for Pregnancy in 1st Trimester with Abnormal Thyroid Function Tests
Single Most Likely Diagnosis
- Hyperthyroidism due to Graves' disease: This condition is characterized by low TSH, elevated free T4, and elevated total T3 levels. The symptoms and laboratory findings presented are consistent with hyperthyroidism, and Graves' disease is a common cause of hyperthyroidism in pregnancy.
Other Likely Diagnoses
- Gestational transient thyrotoxicosis: This condition occurs due to the stimulatory effect of human chorionic gonadotropin (hCG) on the thyroid gland, leading to elevated thyroid hormone levels and suppressed TSH. It is a common cause of thyrotoxicosis in early pregnancy.
- Toxic multinodular goiter or solitary toxic nodule: Although less common in pregnancy, these conditions can cause hyperthyroidism and should be considered in the differential diagnosis.
- Thyroiditis (e.g., subacute or silent thyroiditis): Thyroiditis can cause a transient hyperthyroid phase due to the release of preformed thyroid hormones from the damaged gland.
Do Not Miss Diagnoses
- TSH receptor antibody-positive hyperthyroidism: This condition can be associated with an increased risk of neonatal thyrotoxicosis and requires prompt identification and management.
- Pituitary thyroid-stimulating hormone (TSH) secreting tumor: Although rare, this condition can cause hyperthyroidism and requires early diagnosis to prevent complications.
Rare Diagnoses
- Struma ovarii: A rare ovarian tumor that can produce thyroid hormones, leading to hyperthyroidism.
- Familial dysalbuminemic hyperthyroxinemia: A rare genetic disorder that affects the binding of T4 to albumin, leading to elevated total T4 levels but normal free T4 levels.
- Thyroid hormone resistance: A rare condition characterized by reduced sensitivity to thyroid hormones, which can lead to elevated thyroid hormone levels and nonsuppressed TSH.