Multinodular goitre

Any patients in whom a solitary nodule, suspicious or dominant nodule within the gland, or with palpable lymph nodes requires urgent ultrasound guided aspiration.

It is standard practise to use propylthiouracil rather than carbimazole in patients who may be or are planning pregnancy.

Patients with uncontrolled thyrotoxicosis should be advised to avoid pregnancy until biochemical control is achieved due to the risk of miscarriage. Treatment during pregnancy requires close monitoring typically every six weeks.

Radioactive iodine is contraindicated in pregnant or breast feeding individuals. Women should be advised to avoid conception for six months and men should avoid fathering children for four months following radioactive iodine treatment.

All patients with severe thyrotoxicosis should be considered for immediate medical treatment before long term decisions are taken.

All patients must receive written and verbal warnings about possible side effects of drug therapy.

Exact treatment depends on the severity of thyrotoxicosis. Doses as low as 5-10mg carbimazole may be appropriate in asymptomatic patients with mild biochemical disease.  With more severe disease, a typical starting dose is 40mg carbimazole daily. 

All patients should receive instructions as to the timing of dose reduction and firm arrangements made for serial monitoring. Appropriate dose reduction will depend on symptom control, and on the rapidity of the fall in free thyroxine levels in the early stages, as TSH does not tend to respond as quickly to treatment. Typical monitoring intervals are every six weeks, with dose reduction from 40mg, to 20mg, 15mg, 10mg and then to maintenance therapy of 5mg. 

Long term treatment should be monitored with serum TSH, aiming for a level within the normal range with complete resolution of all symptoms.

Some patients with toxic nodular goitres may choose long term medical therapy. Patients need to be warned that this treatment will be lifelong as hyperthyroidism secondary to multinodular goitres does not tend to remit. Antithyroid drugs are thus usually used short term prior to radioactive iodine therapy.  

Radioactive iodine is the treatment of choice for most patients. It will prevent future growth and reduce the size of most goitres by up to 50% and so is particularly suitable for modest sized goitres. Radioactive iodine is also the treatment of choice for toxic nodular goitres which will otherwise require life long anti-thyroid drugs.

However, it is usual to start medical treatment at presentation in patients with severe thyrotoxicosis in order to allow them to make an informed decision regarding long term management. Written information should be given to all patients on the different treatments available, and they should be warned specifically about standard radiation safety precautions, the possibility of transient thyroid swelling, the need for long term monitoring and possibile thyroxine requirements.

Radioactive iodine is contraindicated in pregnant or breast feeding individuals. Women should be advised to avoid conception for six months, and men should avoid fathering children for four months following radioactive iodine treatment. 

Thyroid function should be assessed at least every three months for the first year after radioactive iodine, and then annually thereafter for emerging hypothyroidism or for recurrent thyrotoxicosis.

Subsequent hypothyroidism should be treated conventionally.

Subsequent recurrence of hyperthyroidism may occur, though this is unusual, and should be treated with a repeat application of radioactive iodine.

With very large goitres, where cosmetic symptoms are severe or where there are definite obstructive symptoms, surgery is the standard treatment, although tracheal deviation or narrowing are not absolute contraindications to radioactive iodine.

Patients should be warned that surgery cannot prevent future re-growth or hyperthyroidism in all cases.

Most patients with multinodular goitres will receive radioactive iodine treatment and so require annual thyroid stimulating hormone (TSH) measurement to monitor thyroxine replacement only.

Patients who have not required treatment should also have their TSH monitored on an annual basis. Permanent suppression of their TSH should prompt a review of whether radioactive iodine or other treatments are now indicated. Long term low TSH is associated with osteoporosis and atrial fibrillation. Consider bone densitometry scanning in such cases. 

Asymptomatic goitres of any size may not necessarily require treatment. Increasing size, TSH suppression, frank thyrotoxicosis, osteoporosis, or atrial fibrillation should all inform the decision whether treatment is indicated in an individual case.