Multinodular Goitre

INSTRUCTION

Examine this patient's neck.

SALIENT FEATURES

History

· Strider (trachea must be narrowed to 20-30% for this symptom).

· Hoarseness of voice (due to pressure on recurrent laryngeal nerve; suggests thyroid malignancy).

· Acute painful enlargement (suggests bleeding into thyroid nodule).

· Suffusion of face when the patient raises the arms above the head (suggests substernal goitre).

· Dysphagia.

· Deafness (if due to eighth cranial nerve involvement suggests Pendred's syndrome; rare).

· Symptoms of thyroid hyper- or hypofunction.

Examination

· Middle-aged or elderly patient.

· Multinodular goitre.

· Atrial fibrillation.

· Signs of thyrotoxicosis .

DIAGNOSIS

This patient has a multinodular goitre (lesion) and is hyperthyroid with atrial fibrillation

(functional status).

QUESTIONS

What is the natural history of thyrotoxicosis in nodular goitre?

It is permanent and there are no spontaneous remissions; therefore, antithyroid drugs

to decrease thyroid hormone secretion are not an appropriate long-term therapy.

How would you investigate a nodular goitre?

· Serum thyrotrophin and tree thyroxine should be measured to identify those with subclinical or overt hyperthyroidism.

· Uhrasonography of the thyroid gland indicates whether the goitre is cystic or solid.

· If nodule is solid, perform a radioisotope scan to indicate whether it is hot or cold.

· If cold nodule, fine-needle aspiration.

· Patients with features of tracheal compression (inspiratory stridor and dyspnoea) should undergo CT or MRI of the neck and upper thorax, and pulmonary function tests, especially flow-volume loop studies. When CT is used, iodinated contrast agents should not be given because of the risk of inducing hyperthyroidism.

How would you treat such a patient?

· Beta-blockers to control thyrotoxicosis.

· Warfarin in atrial fibrillation to prevent embolic complications.

· Radioiodine for hyperthyroidism.

· Surgery if the patient refuses radioiodine, for large multinodular goitres or malignancy.

What are the indications for treatment of patients with non-toxic multinodular

goitre?

· Compression of the trachea or oesophagus and venous outflow obstruction.

· Growth of the goitre, especially where there is intrathoracic extension.

· Neck discomfort or cosmetic issues.

What treatment options are available for non-toxic multinodular goitre ?

Surgery

Standard therapy, especially when rapid decompression of vital structures is required. It allows pathological examination of the thyroid. Disadvantages include postoperative tracheal obstruction, recurrent laryngeal nerve injury, hypo-parathyroidism, hypothyroidism and goitre recurrence.

Thyroxine

Alternative to surgery in young patients with small goitres. Its disadvantage is that it causes only a small decrease in thyroid volume; long-term efficacy is not known; decrease in bone mineral density in postmenopausal women; possible cardiac side effects.

Radioiodine

An alternative to surgery in elderly patients and in those with cardiopulmonary disease. It results in a substantial decrease in thyroid volume and improvement of compressive symptoms in most patients. Disadvantages include: it only causes a gradual decrease in thyroid volume; radiation thyroiditis (usually mild); radiation-induced thyroid dysfunction (hyperthyroidism in 5%, hypothyroidism in 20-30%); possible risk of radiation-induced cancer (N Engl J Med 1998; 338: 143847).

What treatment options are available for toxic multinodular goitre?

Treatment is always indicated when overt hyperthyroidism is present. In cases of subclinical hyperthyroidism, treatment is advisable in elderly patients and in younger ones who are at risk for cardiac disease or osteoporosis. The treatment options available are:

Antithyroid drugs

Valuable as pretreatment for surgery; valuable before and after radioiodine treat-ment in elderly patients and those with concurrent health problems; long-term treatment is 'recommended only when other therapies cannot be used. The dis-advantages ale that the treatment is lifelong and there are adverse effects such as agranulocytosis.

Surgery

Should be considered for large goitres when rapid relief is needed. The other advantage is that it provides tissue for a pathological diagnosis. Disadvantages include surgical mortality and morbidity; hypothyroidism, persistence or recurrence of hyperthyroidism.

Radioiodine

An appealing option in the majority of the patients because it is highly effective for reversal of hyperthyroidism. The disadvantages include a gradual diminution of the hyperthyroid state, more than one dose may be necessary, hypothyroidism (<20%); theoretical risk of radiation-induced cancer (N Engl J Med 1998; 338:1438-47).

ADVANCED-LEVEL QUESTIONS

How do you differentiate between Graves' disease and toxic nodular goitre ?

Graves' disease ( Toxic nodular goiter )

Younger age group

Diffuse goitre

Eye signs common

Atrial fibrillation uncommon

Other autoimmune diseases common

Older individuals

Nodular enlargement of the gland

Eye signs rare

Atrial fibrillation common

(about 40% of the patients)

Other autoimmune diseases uncommon

What factors influence the decision to proceed to radiotherapy?

Patient's age, sex, diagnosis, severity of hyperthyroidism, presence of other medical conditions, access to radioiodine (I-131), and patient and doctor preference