Goitre

Causes:

Physiological:

• Puberty
• Pregnancy

Autoimmune:

• Grave’s disease
• Hashimoto’s disease

Thyroiditis:

• Acute (De Quervain’s thyroiditis)
• Chronic fibrotic (Reidel’s thyroiditis)

Iodine deficiency (endemic goitre)

Dyshormonogenesis

Goitrogens (e.g. sulphonylureas)

Types:

Simple

Multiple nodular

Solitary nodular

Fibrotic

Malignant:

• Adenoma
• Carcinoma
• Lymphoma

Simple goitre:

In this instance, no clear cause is found for enlargement of the thyroid, which is usually smooth and soft. It may be associated with thyroid growth-stimulating antibodies.

Multiple nodular goitre:

• Most common type of goitre (especially in older patients)
• Patient is usually euthyroid, but may be hyperthyroid or borderline
• Suppressed TSH levels but normal T₄ and T₃
• Most common cause of tracheal and/or oesophageal compression and may cause laryngeal nerve palsy

Solitary nodular goitre:

• Presents a difficult diagnostic problem

A history of:

• Pain
• Rapid enlargement of the thyroid
• Associated lymph nodes

These symptoms suggest the possibility of a thyroid carcinoma. However, the majority of such nodules are cystic or benign and, indeed, may simply be the largest solitary nodule of a multinodular goitre.

Risk factors for malignancy include:

• Previous irradiation
• Longstanding iodine deficiency
• Familial history

Solitary toxic nodules (Plummer’s syndrome) are quite uncommon and may be associated with T₃ production.

Fibrotic goitre (Reidel’s thyroiditis):

• Rare
• Usually produces a ‘woody’ gland
• Associated with other midline fibrosis and is often difficult to distinguish from carcinoma, being irregular and hard

Investigations:

Thyroid function tests (normal in brackets):

• TSH (0.5-5mU/L)
• T4 (70-140mmol/L)
• T3 (1.2-3nmol/L)

Chest and thoracic inlet X-rays

Fine needle aspiration (FNA):

• In patients with a solitary nodule or a dominant nodule in a multinodular goitre, there is a 5% chance of malignancy. In view of this, a FNA is performed.

Ultrasound:

• Good for delineating nodules
• Can demonstrate whether the nodules are cystic or solid

Thyroid scan:

• Uses either ¹²⁵I or ¹³¹I
• Useful in distinguishing between functioning (hot) or non-functioning (cold) nodules
• A hot nodule is rarely malignant
• A cold nodule is malignant in 10% of cases

Treatment:

During puberty or pregnancy, a goitre associated with euthyroidism rarely requires intervention. If euthyroid, the patient should be reassured that spontaneous resolution is likely. In other situations, the patient should be rendered euthyroid.

Indications for surgical intervention are:

• The possibility of malignancy
• Pressure symptoms on the trachea (or, more rarely, the oesophagus)
• Cosmetic reasons