Hyperthyroidism

About Hyperthyroidism

Hyperthyroidism, or an overactive thyroid, occurs when the thyroid produces too much thyroid hormone. The thyroid gland is located in the neck and produces several hormones, which control metabolism. Hyperthyroidism is a common disorder and the most common cause of hyperthyroidism is Graves’ Disease

Hyperthyroidism also can result from nodular goitre, inflammation of the thyroid due to viral infections or other causes, ingestion of excessive amounts of thyroid hormone, and ingestion of excessive iodine. The most common forms of hyperthyroidism include Diffuse Toxic Goiter (Graves’ Disease), Toxic Multinodular Goiter (Plummer Disease), and Toxic Adenoma – together with Subacute Thyroiditis, these conditions constitute 85 – 90% of all causes of Thyrotoxicosis.

Hyperthyroid Symptoms: Overactive Thyroid

Initially, many patients who are hyperthyroid do not experience clear symptoms and therefore do not get diagnosed with hyperthyroidism. In older people, some or all of the typical symptoms of hyperthyroidism may be absent, and the patient may just lose weight or become depressed.

Symptoms of hyperthyroidism – If you are hyperthyroid you may have any or all of the following symptoms:

• Increased appetite with weight loss
• Intolerance of warm weather, sweating, tremor
• Infrequent menstruation
• Emotional lability, irritability and nervousness
• Fast heart rate and palpitations
• Frequent bowel movements
• Thyroid enlargement causing a lump in the neck
• A thick redness on the front of legs (pretibial myxdemia) and typically occurs with Graves’ Disease
• Thin, delicate skin and irregular fingernail and hair growth
• Menstrual disturbance, such as decreased flow
• Mental disturbances
• Sleep disturbances, including insomnia
• Eye symptoms including; changes in vision, eye irritation or exophthalmos, which is a protrusion of the eyes that typically occurs with Graves’ Disease

Subclinical Hyperthyroidism

• Subclinical hyperthyroidism is defined as a low serum TSH concentration in an asymptomatic person with normal serum thyroid hormone concentrations – this is more common in older people and is detected by measuring TSH
• Subclinical hyperthyroidism is a common thyroid disease and consistent evidence indicates that ‘subclinical’ hyperthyroidism reduces quality of life, affecting both the mental and physical components of well-being
• It may be caused by many factors including excessive TSH suppressive therapy – for example thyroxine treatment for benign thyroid nodular disease, differentiated thyroid cancer, or hormone over-replacement in patients with hypothyroidism are the most frequent causes
• Subclinical hyperthyroidism exerts many significant effects on the cardiovascular system; it is usually associated with a higher heart rate and a higher risk of arrhythmias, and decreased exercise tolerance. It is well known that these abnormalities usually precede the onset of a more severe cardiovascular disease, potentially contributing to increased cardiovascular morbidity and mortality
• In addition, it is becoming increasingly apparent that subclinical hyperthyroidism may accelerate the development of osteoporosis and increased bone vulnerability to trauma, particularly in postmenopausal women with a pre-existing predisposition
• Subclinical hyperthyroidism and its related clinical manifestations are reversible and may be prevented by timely treatment

Hyperthyroidism Treatment

Treatment varies depending on the cause of hyperthyroidism and the severity of symptoms and options include:

Antithyroid Medications

• Antithyroid drugs may be prescribed to suppress the production and release of thyroid hormones by inhibiting the use of iodine by the thyroid
• Side effects may include skin rash, joint pains, fever, low white count and jaundice

Other Medications

• Occasionally, drugs known as beta adrenergic blocking agents are prescribed to block the action of thyroid hormone on the heart and thus relieve symptoms
• Unless the hyperthyroidism is caused by thyroiditis, these drugs are used in conjunction with other treatments

Radioactive Iodine

•  This is often the initial treatment of hyperthyroidism caused by Graves’ disease
• A radioactive iodine tablet is ingested and then taken up by thyroid cells
• The overactive cells are damaged so that the thyroid can shrink in size and produce hormones at normal levels
• Although this is a safe treatment, most people eventually become hypothyroid after radioactive iodine therapy and therefore require lifelong thyroid hormone replacement therapy
• Radioactive iodine therapy cannot be given to pregnant women or those who are breastfeeding

Surgery

Surgery is very effective for the treatment hyperthyroid conditions and cures around 95% of patients.
Surgical therapy is usually recommended for:

1. People where radioactive iodine and medications are not effective or appropriate
2. Young individuals
3. Patients with one or more large nodules
4. Those with obstructive symptoms, problems with breathing or eating and drinking
5. Patients with dominant non-functioning or suspicious nodules
6. Patients who are pregnant
7. Patients who require a rapid resolution of hyperthyroid symptoms
8. If the thyroid is removed, lifelong thyroid hormone replacement therapy is required

Before surgery

Before surgery for an overactive thyroid you will need treatment for your symptoms to reduce the risk of surgery – this may include:

• Medication to lower the amount of thyroid hormone in the blood
• Medication to slow the heart rate
• Iodine supplements (Lugol’s iodine) to reduce the flow of blood in the thyroid gland

If you have any questions about hyperthyroidism or thyroid disease, contact your local doctor, who will arrange for you to see a thyroid surgeon.