Thyrotoxicosis or hyperthyroidism

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

Patients with suspected eye disease require evaluation by an endocrinologist or ophthalmologist experienced in Graves' ophthalmopathy. Simple lubricants, avoidance of smoky environments and avoidance of bright sunlight and strong winds by wearing sunglasses should be advised in all patients with Graves’ ophthalmopathy.

Patients with reduced acuity require urgent assessment for the consideration of medical or surgical decompression. Radiotherapy may also be considered in the acute phase.

Patients with incomplete lid closure require taping at night to protect from corneal abrasion, and also require rapid specialist ophthalmological assessment.

Patients with asymmetry, periorbital oedema and abnormalities of external ocular movements also require assessment for consideration of steroid or other medical therapy.

Prism spectacles may be helpful in diplopia. Orbital muscle surgery, and reconstructive and corrective orbital and lid surgery are usually not conducted in the acute phase, but patients should be reassured that treatment is available and is highly effective.

Smoking increases the risk and severity of ophthalmopathy.

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.

Any patient with severe clinical or biochemical thyrotoxicosis requires immediate medical treatment, before long term decisions are taken. All patients must also receive verbal and written safety warnings regarding drug therapy, and clear instructions on the need for serial blood tests and dose adjustment.

Usual treatment starts with high dose carbimazole, for example 40-60mg daily, though lower doses (5-10mg) may be appropriate in those with milder disease.

Patients with tachycardia or other severe symptoms are also usually treated with beta blockade, for example propranolol 120-240mg daily in divided doses.

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.

Treatment duration and likelihood of relapse should be discussed with all patients at the start of a treatment course, and other options discussed.

Typical treatment courses for Graves' thyrotoxicosis are 18 months. All patients with auto-immune hyperthyroidism should be warned of a 50% chance of disease recurrence after their initial treatment course. Male patients, older patients, those with high antibody titres, those with previous episodes and those with severe biochemical disease are at the highest risk of future recurrence.

Patients with hyperthyroidism secondary to thyroid nodules or multinodular goitres will need life long medical treatment if they do not choose to have radioactive iodine.

Dose titration may be difficult or inappropriate in occasional circumstances. In such cases, high dose carbimazole (40-60mg) may be continued, and thyroxine added once the serum thyroxine falls to within the normal range. Thyroxine dose is then adjusted according to symptoms and aiming for a normal serum TSH level.

It is usual to start medical treatment at presentation particularly in those with severe biochemical disease in order to allow them to make an informed decision regarding long term management. However, radioactive iodine is the best long term treatment for thyrotoxicosis in most cases.

Detailed guidance on the indications and precautions needed for radioactive iodine are available. Radioactive iodine is highly effective at rendering patients euthyroid, usually after one treatment, and offers the advantage of preventing future recurrence in auto-immune thyroid disease. Patients must be warned about standard radiation precautions, and given written information about this and other available treatments. Patients should also be warned that transient thyroid swelling may occur, repeat applications may be necessary, long term monitoring is required, and hypothyroidism requiring thyroxine replacement therapy may ensue.

Radioactive iodine is absolutely contraindicated in pregnancy. Women should also 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, and should be treated with a repeat application of radioactive iodine.

Radioactive iodine should be discussed with an experienced ophthalmologist in the case of severe eye disease. Mild to moderate eye disease does not preclude the use of radioactive iodine, but it is standard practise to render the patient euthyroid medically and wait for the eye disease to become quiescent first, and then to protect the eyes with glucocorticoid therapy to reduce the risk of exacerbation.

Typical doses would be prednisolone 30mg starting on the day of the treatment, continuing for 14 days, then reducing by 5mg every 14 days thereafter. This should be prescribed with bone protection, for example alendronate, calcium and vitamin D.

Surgery is rarely recommended as a first line treatment for straight forward thyrotoxicosis. However, all options should be discussed with patients to allow an informed choice to be made.

Patients who do not tolerate medical therapy, or who require life long treatment but are unsuitable for radioactive iodine, should strongly consider surgery as a definitive treatment. Surgery may also be used during the second trimester of pregnancy, if severe thyrotoxicosis cannot be controlled medically. Patients with obstructive symptoms from nodular disease are also recommended surgery in most cases. 

After treatment for thyrotoxicosis, most patients can be followed up by their family physician long term with an annual TSH alone. This is sufficient to monitor thyroxine replacement, or detect early recurrence of thyrotoxicosis. Patients will auto-immune thyroid disease are at increased risk of developing further auto-immune conditions, though routine monitoring is not generally necessary if their initial screening tests were satisfactory.