goiter

Goiter is enlargement of the thyroid gland, in the front of the neck. It may involve the entire gland or be nodular. Many goiters are asymptomatic, while others cause a visible swelling or a feeling of fullness. Goiter is a sign of an underlying thyroid disorder rather than a disease itself.

Causes differ by region and age. The most common global cause is iodine deficiency, producing endemic goiter. In areas with adequate iodine, goiter often results from autoimmune thyroid disease such as Hashimoto's or Graves', from benign thyroid nodules, or from medications such as lithium or amiodarone. Goiter can be diffuse or nodular; when linked to hyperthyroidism it is toxic.

Symptoms depend on size and the underlying condition. A large goiter can press on the windpipe or esophagus, causing coughing, breathing difficulties, or trouble swallowing. Hyperthyroid-related goiters may cause rapid heartbeat and weight loss, while hypothyroid forms can cause fatigue and weight gain. Some goiters cause no symptoms beyond neck swelling.

Diagnosis starts with history and examination, then tests of thyroid function (TSH and free T4) and thyroid antibodies. Ultrasound assesses structure and nodules; fine-needle aspiration biopsy evaluates suspicious nodules. In selected cases, radioactive iodine uptake scans provide further information.

Treatment targets the underlying cause and the goiter's size. Iodine supplementation treats deficiency; levothyroxine treats hypothyroidism; antithyroid drugs or radioactive iodine treat hyperthyroidism. Large or compressive goiters or suspicious nodules may require surgery. Prevention focuses on adequate iodine intake, commonly via iodized salt.