Which statement best describes the thyroid function pattern in autoimmune Hashimoto thyroiditis?

• A. Elevated TSH with high T4
• B. Normal TSH with low T3
• C. Low TSH with high T4
• D. Elevated TSH with low T4 and T3

Answer: (D)

Hashimoto thyroiditis causes autoimmune destruction of the thyroid gland, so it produces less thyroid hormone (T4 and T3). Because the body’s cells are not getting enough thyroid hormone, the pituitary responds by releasing more TSH in an attempt to stimulate the thyroid. This feedback loop leads to a pattern of high TSH with low levels of thyroid hormones. In the typical Hashimoto pattern, you see elevated TSH and reduced free T4 (and often reduced free T3) due to insufficient hormone production by the damaged gland. This is distinct from hyperthyroid patterns, where TSH is low or suppressed and T4/T3 are high. So the statement that best describes Hashimoto’s thyroiditis is elevated TSH with low T4 and T3.