Goiter is any abnormal enlargement of the thyroid gland. The condition has various causes, with the most common worldwide being iodine deficiency. In the US, however, Hashimoto's and Graves' disease are more common etiologies. Goiters can be classified based on their morphology, function, or dignity (benign or malignant). Symptoms depend on etiology and are often absent. However, patients may present with hyperthyroidism or hypothyroidism. Large goiters may also cause obstructive symptoms due to compression of the trachea and/or the esophagus. Diagnosis is established based on clinical examination, laboratory tests, and imaging techniques. Management depends on the underlying condition and may include administering iodine (for treating nontoxic euthyroid goiter) or performing surgery (e.g., for treating local compression or thyroid cancers).
Thyroid gland versus goiter
- Normal adult thyroid gland
- Growth pattern of goiter
- Goiter size: see ”Classification of goiter by palpation” below.
Thyroid function of goiter
Nontoxic goiter: normal TSH, fT3, and fT4 levels
- E.g., Iodine deficiency
- Toxic goiter: increased thyroid hormone production
Hypothyroid goiter: decreased thyroid hormone production
- E.g., Hashimoto's disease, congenital hypothyroid goiter
Dignity of goiter
- Patients are commonly asymptomatic.
- Altered hormone metabolism may occur
- Symptoms of
- Symptoms of
- Obstructive symptoms
- Best initial step: palpation of thyroid gland (see “Classification of goiter by palpation” below)
- Laboratory tests
- Imaging: determination of goiter size, nodularity, and consistency
Classification of goiter by palpation
According to the World Health Organization (WHO) classification:
- Grade 0: no goiter is palpable or visible.
- Grade 1: palpable goiter, not visible when neck is held in normal position
- Grade 2: a clearly swollen neck (also visible in normal position of the neck) that is consistent with a goiter on palpation
- Treatment is not needed if the patient is asymptomatic.
- Schedule follow-ups for possible dysfunctional thyroid and/or obstructive symptoms.
- Large goiter (> 80 mL)
- Iodine deficiency: iodine supplementation
- In other cases, goiter treatment varies depending on the exact etiology (see “Etiology” above).