Hashimoto's thyroiditis is characterized by which antibody profile and clinical presentation?

• A. Hyperthyroidism with thyroid-stimulating antibodies
• B. Antithyroid peroxidase antibodies and antithyroglobulin antibodies; chronic disease presents with hypothyroidism
• C. Hyperthyroidism due to TSH receptor antibodies
• D. Normal Thyroid Function

Answer: (B)

Hashimoto's thyroiditis is an autoimmune attack on the thyroid that gradually destroys its ability to produce thyroid hormones. The immune response is usually reflected by antibodies against thyroid proteins, most notably anti-thyroid peroxidase (anti-TPO) antibodies, and often anti-thyroglobulin antibodies as well. This antibody profile signals autoimmune thyroid destruction, which over time leads to reduced thyroid function.

Clinically, this typically presents as a chronic, progressive hypothyroidism: fatigue, weight gain, cold intolerance, dry skin, constipation, hair loss, and a sometimes palpable, firm, non-tender goiter. Hyperthyroidism due to stimulating antibodies (as seen in Graves disease) is not the pattern here, and normal thyroid function is not characteristic once Hashimoto’s has progressed. So the combination of anti-TPO and anti-thyroglobulin antibodies with a chronic course of hypothyroidism best matches Hashimoto's.