High TSH, low FT3 and FT4

Under normal circumstances, TSH refers to thyroid-stimulating hormone, FT3 refers to free triiodothyronine, and FT4 refers to free thyroxine. Elevated TSH with low FT3 and FT4 levels may be caused by medication effects, hypothyroidism, central hypothyroidism, Hashimoto's thyroiditis, or thyroid hormone resistance syndrome. The specific causes are analyzed as follows:

1. Medication effects

Certain medications, such as glipizide tablets and gliquidone tablets, can interfere with the synthesis or release of thyroid hormones, leading to increased TSH and decreased FT3 and FT4 levels.

2. Hypothyroidism

Insufficient secretion of thyroid hormones leads to hypothyroidism, which is one of the more common causes of elevated TSH and reduced FT3 and FT4 levels.

3. Central hypothyroidism

Central hypothyroidism results from diseases affecting the hypothalamus or pituitary gland. These conditions may disrupt the release of thyrotropin-releasing hormone (TRH) and TSH from the pituitary gland, impairing the feedback regulation of TSH.

4. Hashimoto's thyroiditis

Hashimoto's thyroiditis, caused by autoimmune antibodies attacking the thyroid gland, can also lead to elevated TSH and decreased FT3 and FT4 levels.

5. Thyroid hormone resistance syndrome

Thyroid hormone resistance syndrome is a rare genetic disorder in which patients typically have normal circulating thyroid hormone levels, but reduced tissue responsiveness to thyroid hormones, resulting in elevated TSH and decreased FT3 and FT4 levels.

If patients experience the above symptoms, they should seek medical attention promptly to determine the underlying cause and receive targeted treatment. Additionally, maintaining healthy lifestyle habits and avoiding spicy or irritating foods is recommended to support recovery.