Goitre refers to an abnormal enlargement of the thyroid gland, which can vary in size from barely noticeable to visibly large neck swelling.
Physiological Background:
The thyroid gland synthesizes thyroid hormones (thyroxine/T4 and triiodothyronine/T3) that regulate metabolism and multiple body systems.
Causes of Goitre
Goitre can arise from multiple causes including:
- Iodine deficiency: Most common worldwide; insufficient iodine intake impairs thyroid hormone synthesis, causing gland hypertrophy.
- Thyroid dysfunction:
- Hyperthyroidism (overactive thyroid) — e.g., Graves’ disease or toxic multinodular goitre.
- Hypothyroidism (underactive thyroid) — e.g., Hashimoto’s thyroiditis.
- Physiological hormone changes: During puberty, pregnancy, or menopause.
- Medications: Lithium and others affecting thyroid function.
- Thyroiditis: Inflammation due to autoimmune or infectious causes.
- Neoplasms: Thyroid nodules, cysts, or cancer.
- Radiation exposure: Prior radiotherapy to the neck or chest.
Classification
| Type | Description | Notes |
|---|---|---|
| Simple (Non-toxic) Goitre | Diffuse enlargement usually due to iodine deficiency or defects in hormone synthesis. | Usually euthyroid. |
| Toxic Goitre | Hyperfunctioning gland producing excess thyroid hormones (T3, T4). | Causes thyrotoxicosis symptoms. |
| Neoplastic Goitre | Presence of benign or malignant nodules or thyroiditis (e.g., Hashimoto’s). | Requires cytological assessment. |
| Infectious Goitre | Rare; caused by infections such as tuberculosis. | More common in endemic areas. |
Clinical Features
- Most patients are asymptomatic.
- Local compressive symptoms:
- Neck fullness or visible swelling.
- Dysphagia (difficulty swallowing).
- Stridor or dyspnea (if large goitre compresses airway).
- Hoarseness (recurrent laryngeal nerve involvement).
- Engorged neck veins (venous congestion).
- Hyperthyroid symptoms (if toxic goitre):
- Weight loss despite increased appetite.
- Heat intolerance, sweating.
- Palpitations, tachycardia, arrhythmias.
- Tremors, anxiety.
- Menstrual irregularities.
- Ophthalmopathy in Graves’ disease (exophthalmos, lid lag).
Investigations
- Thyroid function tests: TSH, free T4, free T3 to assess thyroid status.
- Imaging:
- Ultrasound of the thyroid — assesses gland size, nodularity, and cysts.
- Chest and neck X-rays — to evaluate tracheal compression or retrosternal extension.
- Fine Needle Aspiration Cytology (FNAC):
- Indicated for suspicious nodules to rule out malignancy.
Management
General Principles
Treatment depends on the cause and clinical presentation.
Non-Toxic Simple Goitre
- Reassurance is key for asymptomatic, euthyroid patients.
- Thyroxine therapy (50–150 mcg daily) may be trialed for 6 months to suppress TSH and reduce gland size.
- If no improvement, stop therapy and monitor.
Toxic Goitre (Hyperthyroidism)
- Medical therapy:
- Antithyroid drugs:
- Carbimazole 15–20 mg three times daily for 3-4 weeks, then taper to maintenance dose (5–30 mg daily).
- Alternatively, Propylthiouracil (PTU) up to 300 mg/day in divided doses (used mainly in pregnancy or thyroid storm).
- Beta-blockers (e.g., propranolol 60–240 mg daily in divided doses) to control adrenergic symptoms.
- Radioactive Iodine Ablation:
- Recommended if medical therapy fails after 12–24 months.
- Contraindicated in pregnancy, breastfeeding, and young children.
- Preferred for patients aged >35 years and those who completed childbearing.
- Surgery (Thyroidectomy):
Indications include:
- Toxic goitre refractory to medical therapy.
- Large goiters causing compressive symptoms.
- Suspicion or confirmation of malignancy.
- Pregnancy with intolerance to medical therapy.
- Patient preference or contraindication to radioactive iodine.
Summary
| Condition | Treatment Modalities | Notes |
|---|---|---|
| Non-toxic goitre | Observation, thyroxine suppression | Monitor size and function |
| Toxic goitre (hyperthyroidism) | Antithyroid drugs, beta-blockers, radioactive iodine, surgery | Long-term management needed |
| Suspicious nodules | FNAC, surgery if malignant | Early diagnosis critical |
| Compressive symptoms | Surgery | Relief of airway or esophageal compromise |
