Simple Goitre

Simple (non-toxic) goitre is a diffuse enlargement of the thyroid gland with normal thyroid function and no inflammation or malignancy. It results from long standing stimulation of the thyroid by raised thyroid stimulating hormone or growth factors, most often due to iodine deficiency, and it can evolve into a multinodular goitre over years.

• Grading: grade 0 no goitre; grade 1 palpable but not visible with the neck in a normal position; grade 2 visible. Normal thyroid volume on ultrasound is up to 18 mL in women and 25 mL in men (up to 0.5 mL per year of age plus growth in children).
• Causes: iodine deficiency (endemic goitre, defined as more than 5 percent of school children affected), goitrogens (cassava, millet, cabbage, soy, smoking), excess iodine, drugs (lithium, amiodarone, sulfonamides, thionamides), puberty and pregnancy (physiological enlargement), early Hashimoto thyroiditis, and genetic dyshormonogenesis (family clustering).
• Sporadic goitre in iodine sufficient areas is commoner in women (up to 4 to 5 times) and is often familial.
• Complications: compression of the trachea, oesophagus and recurrent laryngeal nerve, retrosternal extension, development of nodules, thyrotoxicosis (toxic multinodular goitre after iodine exposure), haemorrhage into a cyst, and rarely malignancy.

• Visible or palpable smooth enlargement of the neck, moving on swallowing; often painless; fullness, tightness or a cosmetic concern.
• Compressive symptoms: dysphagia, dyspnoea (worse when the arms are raised, the Pemberton sign), stridor, cough, hoarseness, positional breathlessness at night.
• No symptoms of thyroid dysfunction; check for hypothyroid or hyperthyroid features.
• Examination: thyroid size and consistency, nodularity, tenderness, bruit, retrosternal extension (cannot get below the goitre), tracheal deviation, cervical lymph nodes, and signs of obstruction (facial plethora and neck vein distension with raised arms).
• Red flags: rapid enlargement, a hard fixed nodule, new hoarseness, cervical lymphadenopathy, stridor, haemoptysis, family history of medullary thyroid cancer or multiple endocrine neoplasia, and previous neck irradiation.

• Thyroid stimulating hormone and free thyroxine (and free triiodothyronine if thyroid stimulating hormone is suppressed); anti-thyroid peroxidase antibodies.
• Thyroid ultrasound to measure volume, find nodules, and examine the structure (diffuse enlargement with uniform echo pattern).
• Fine needle aspiration cytology for a nodule 1 cm or more with suspicious ultrasound features (hypoechoic, irregular margins, microcalcifications, taller than wide), or 1.5 to 2 cm or more with intermediate features, or a nodule with growth.
• Serum calcitonin if medullary carcinoma is suspected (family history); thyroglobulin is not diagnostic.
• Radioisotope scan when thyroid stimulating hormone is low.
• Computed tomography or magnetic resonance imaging (without iodinated contrast when thyroid disease is active) for retrosternal extension or tracheal compression; flow volume loop for functional airway obstruction.
• Urinary iodine for population or individual iodine status.
• Differentials: Hashimoto thyroiditis, Graves disease, multinodular goitre, thyroid cancer, subacute thyroiditis, thyroid lymphoma, non-thyroid neck mass.

Observation (most patients)

• No treatment for small, asymptomatic, euthyroid goitres. Repeat thyroid stimulating hormone and clinical review yearly, and ultrasound at 12 to 24 months or if growth occurs.

Treat the cause

• Iodine deficiency: iodised salt and diet, or potassium iodide 150 micrograms daily (200 micrograms in pregnancy and breastfeeding); in endemic areas, iodised oil 400 mg orally once yearly. Monitor thyroid function 4 to 8 weeks after starting iodine in nodular goitre because of iodine induced thyrotoxicosis.
• Stop goitrogens when possible (cassava, smoking, excess iodine, lithium or amiodarone when alternatives exist).
• Autoimmune thyroiditis with hypothyroidism: levothyroxine 1.6 micrograms/kg daily, adjusted every 6 to 8 weeks.

Levothyroxine suppression

• It is not advised in iodine sufficient areas, because shrinkage is modest (about 20 to 30 percent), growth returns after stopping, and risks include atrial fibrillation and bone loss. It can be tried for 6 to 12 months in young patients with diffuse goitre in iodine deficient areas: levothyroxine 1 to 1.5 micrograms/kg daily (25 to 50 micrograms starting in older people), aiming at a thyroid stimulating hormone of 0.5 to 1.0 mIU/L, then stop if volume does not fall by 20 to 30 percent.

Procedures (specialist)

• Surgery (total or near total thyroidectomy, with hemithyroidectomy for unilateral disease) for compressive symptoms, retrosternal goitre, suspicious cytology, rapid growth, or cosmetic burden. Risks include recurrent laryngeal nerve injury (1 percent or less), hypoparathyroidism (temporary 10 to 30 percent, permanent 1 to 3 percent), bleeding and need for lifelong levothyroxine (about 1.6 micrograms/kg daily after total thyroidectomy).
• Radioactive iodine (iodine-131) for large goitres in patients unfit for surgery or declining it (reduces volume by 35 to 50 percent at 1 year; recombinant human thyroid stimulating hormone can enhance the effect); risks include hypothyroidism, transient swelling and thyroiditis, radiation precautions, and avoidance in pregnancy and breastfeeding.
• Percutaneous ethanol injection or laser ablation for cystic or small nodules.

Special groups

• Pregnancy: do not give radioiodine; check thyroid function each trimester; maintain adequate iodine; pregnancy can enlarge goitres.
• Children and adolescents: exclude iodine deficiency, hypothyroidism and autoimmune disease; refer to paediatric endocrinology.
• Older adults: take care with levothyroxine because of atrial fibrillation and osteoporosis; compressive symptoms favour surgery or radioiodine.
• Retrosternal goitre with airway compromise: urgent surgical referral.

Follow up

• Annual clinical review and thyroid stimulating hormone; repeat ultrasound if the goitre enlarges or new symptoms appear; refer urgently for suspected malignancy, compression, or stridor.