Atrophic hypothyroidism associated with thyrotropin receptor antibodies

Area of Science:

• Endocrinology
• Immunology

Background:

• Hypothyroidism is commonly caused by Hashimoto's thyroiditis.
• The role of thyrotropin receptor antibodies (TRAbs) in hypothyroidism is an emerging area of research.

Observation:

• A 37-year-old woman presented with symptoms suggestive of hypothyroidism, including edema, weight gain, and hoarseness.
• Initial laboratory tests confirmed hypothyroidism with elevated TSH and low free thyroxine.
• Despite negative thyroid peroxidase antibodies (TPO-Ab) and thyroglobulin antibodies (TgAb), TRAbs were positive, indicating an autoimmune cause.

Findings:

• The patient was diagnosed with autoimmune hypothyroidism despite negative TPO-Ab and TgAb.
• Levothyroxine treatment improved her symptoms and laboratory values.
• Her TRAb levels normalized during pregnancy, and postpartum follow-up showed stable thyroid function without affecting the newborn.

Implications:

• This case highlights the diagnostic challenges in hypothyroidism when TPO-Ab and TgAb are negative.
• TRAb measurements are vital for differentiating autoimmune hypothyroidism, especially in women of childbearing age.
• Further research is needed to understand TRAb-mediated hypothyroidism and develop targeted therapies.