A 40-year-old woman complains of chronic fatigue, aching muscles, and general weakness. Physical examination reveals a modest weight gain, dry skin, and slow reflexes. Laboratory findings include TSH: 10 mU/L (normal range 0.5-5 mU/L), free T4: low to normal. Which of the following is the most likely explanation?

Question

A 40-year-old woman complains of chronic fatigue, aching muscles, and general weakness. Physical examination reveals a modest weight gain, dry skin, and slow reflexes. Laboratory findings include TSH: >10 mU/L (normal range 0.5-5 mU/L), free T4: low to normal. Which of the following is the most likely explanation?

Quizplus · Accepted Answer

The symptoms and lab findings are consistent with hypothyroidism, specifically primary hypothyroidism due to autoimmune thyroid disease (such as Hashimoto's thyroiditis), characterized by elevated TSH and low to normal free T4.  The described symptoms are typical for hypothyroidism. A primary thyroid gland deficiency leads to low T4 levels and high TSH levels. The most common cause of thyroid gland failure is called autoimmune thyroiditis or Hashimoto thyroiditis. It develops slowly due to persistent inflammation of the thyroid caused by the patient's own immune system. Middle-aged women are most commonly affected. The measurement of elevated TSH levels in blood is of high diagnostic value since it helps determine even minor degrees of hypothyroidism. Correct diagnosis is critical because treatment usually continues for life, and stopping of the treatment and reevaluating the original diagnosis is often difficult.

A 40-Year-Old Woman Complains of Chronic Fatigue, Aching Muscles, and General