Toxic Multinodular Goitre
Toxic multinodular goitre (TMNG) is an enlarged thyroid containing multiple nodules, at least one of which produces thyroid hormone autonomously — causing hyperthyroidism.
It is a common cause of hyperthyroidism in older adults, typically over 50.
Last medically reviewed: 1 November 2025
How it develops
Over years, thyroid nodules accumulate genetic changes that allow them to function independently of TSH control — "autonomous" tissue. Initially the rest of the gland compensates by reducing output, but eventually autonomous hormone production exceeds needs.
Unlike Graves’ disease, TMNG is not autoimmune — TRAb antibodies are absent.
Symptoms
Patients may have a long-standing goitre plus hyperthyroid symptoms — weight loss, palpitations, atrial fibrillation risk, heat intolerance. Older patients often present with cardiac symptoms (especially atrial fibrillation) rather than classic hyperthyroid features.
The goitre itself may cause compressive symptoms if large.
Diagnosis and treatment
TSH is suppressed with elevated T4/T3. Ultrasound shows a multinodular gland; radioactive iodine uptake scan shows patchy uptake corresponding to autonomous areas. TRAb testing excludes Graves’ overlap.
Definitive treatment options: radioactive iodine — which treats the whole gland and is often preferred in older patients — or total thyroidectomy, particularly for large compressive goitres. Antithyroid drugs control hormone but rarely provide lasting cure because nodules persist.
Frequently asked questions
Is TMNG cancerous?
The autonomous nodules are almost always benign. However, any dominant nodule should be evaluated with ultrasound and FNAC if it meets suspicious criteria.
Why is RAI often preferred over surgery?
RAI treats the entire gland without surgery and is effective for toxic nodular disease in older patients. Surgery is preferred for very large goitres, compressive symptoms, or patient preference.
Will I become hypothyroid?
Yes — both RAI and total thyroidectomy for TMNG lead to hypothyroidism, managed with lifelong levothyroxine. This is expected and well-controlled.
References & further reading
This page is based on established medical knowledge and guidelines from authoritative sources. Always consult a qualified clinician for personal medical advice.
Ready to discuss your thyroid health?
Book a specialist consultation — in person or by teleconsultation.