What is the condition characterized by low serum T4 and elevated TSH in a 45-year-old woman?

The condition characterized by low serum T4 and elevated TSH is indicative of hypothyroidism. In this scenario, the thyroid gland is not producing sufficient amounts of the hormone thyroxine (T4), which leads to a compensatory increase in thyroid-stimulating hormone (TSH) from the pituitary gland. This feedback mechanism is essential in maintaining thyroid hormone levels; when T4 is low, the body attempts to stimulate the thyroid to produce more by releasing more TSH.

In hypothyroidism, symptoms can include fatigue, weight gain, cold intolerance, and depression due to the overall reduction in metabolic rate that results from insufficient thyroid hormones. Risk factors for developing hypothyroidism include age, gender (more common in women), and autoimmune disorders such as Hashimoto's thyroiditis, which can also lead to low T4 levels.

Thyroiditis refers to inflammation of the thyroid gland, which can cause fluctuations in hormone levels but does not directly indicate low T4 and high TSH, as these can also vary based on the phase of the condition. Goiter, or an enlargement of the thyroid gland, can occur in various thyroid conditions, including both hypothyroidism and hyperthyroidism, but it does not specifically indicate low