Differential Diagnosis for Elevated TPO with Normal TgAB

• Single Most Likely Diagnosis
  • Hashimoto's thyroiditis: This is the most likely diagnosis, as elevated TPO (thyroid peroxidase) antibodies are a hallmark of Hashimoto's, and normal TgAB (thyroglobulin antibodies) do not rule out this condition. Hashimoto's is an autoimmune thyroiditis that can cause hypothyroidism.
• Other Likely Diagnoses
  • Silent thyroiditis: This condition is characterized by inflammation of the thyroid gland, which can lead to elevated TPO antibodies. It may not always present with abnormal TgAB levels.
  • Postpartum thyroiditis: This is a condition that occurs in some women after childbirth, characterized by thyroid inflammation and potentially elevated TPO antibodies, with TgAB levels that can be normal.
  • Subacute thyroiditis: Although TgAB might be more commonly elevated in this condition, some cases can present with elevated TPO and normal TgAB, especially in the early stages.
• Do Not Miss Diagnoses
  • Graves' disease: While less common with normal TgAB, Graves' disease can occasionally present with isolated elevated TPO antibodies. Missing this diagnosis could lead to untreated hyperthyroidism, which has significant health implications.
  • Thyroid lymphoma: A rare condition, but one that could potentially present with elevated TPO antibodies due to the autoimmune nature of the disease. It's crucial not to miss this diagnosis due to its severe prognosis if left untreated.
• Rare Diagnoses
  • De Quervain thyroiditis: A rare form of subacute thyroiditis that might present with elevated TPO antibodies and normal TgAB, though this is less common.
  • Riedel's thyroiditis: A rare form of chronic thyroiditis that could potentially have elevated TPO antibodies. It's characterized by a hard, fibrotic thyroid gland and can be associated with other autoimmune conditions.