Hyperthyroidism is a condition in which there is excessive production and/or secretion of thyroid hormone by the thyroid gland (overactive thyroid). Grave’s disease is the most common cause in the US and most countries. Other causes include; multinodular goiter, toxic adenoma, excessive intake of thyroid hormone, drugs (like iodine and Amiodarone), thyroiditis, excessive iodine load (ingestion or via intravenous contrast medium used in CT scans), and other less common ones like pituitary tumor producing thyroid stimulating hormone (TSH).
Graves disease
Graves disease is an autoimmune disease of the thyroid, named after an Irish physician Robert James Graves who described a case of goiter with eye involvement in the 19th century. This disorder is characterized by the immune system producing antibodies to the receptors of the thyroid resulting in stimulation and excessive production of thyroid hormones (overactive thyroid). This disease tends to be hereditary and can occur at any age, more common in females than males especially during the 2nd and 3rd decade of life.
Unlike other forms of hyperthyroidism Graves disease can also cause bulging of the eyes (a condition called exophthalmos) and thickening of the skin on the shins (Pretibial myxedema)
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Signs and symptoms of hyperthyroidism include:
During a state of hyperthyroidism the body’s functional systems and metabolism speeds up resulting in the following:
Anxiety
Irritability
Heat intolerance
Unintentional Weight loss
Tremors
Frequent bowel movements
Excessive sweating
Fatigue
Enlarged thyroid (goiter)
Bulging eyes and/or double vision if severe (Graves disease)
Rapid heart rate and sometimes irregular heart beat (Arrhythmias)
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Diagnosis and Treatment of Hyperthyroidism
After a physical examination and findings described above, your doctor will send a test to measure the levels of thyroid hormones and Thyroid stimulating hormone (TSH). A classical diagnostic result is that of elevated levels of T4, T3 and very low levels of TSH (sometimes even undetectable). Additionally your doctor can also run a blood test for antibodies directed against the receptors for TSH which will confirm the diagnosis of Graves disease.
A radioactive iodine uptake scan can also be done to measure the activity of the thyroid by how quickly and how much the thyroid takes up this iodine. This test is able to differentiate between overactive thyroid conditions (from graves) and other causes where there is just excessive release of thyroid hormones with low or no activity of the thyroid (thyroiditis). This test may not be necessary when there is no doubt in the diagnosis, however if other transient causes are suspected, like sub acute/transient thyroiditis, this test is essential in confirming the diagnosis thus dictating the form of treatment and long term follow up.
Treatment
Treatment of hyperthyroidism in Graves is aimed at controlling symptoms and/or definitive treatment by destroying or removing the thyroid gland. Often this is achieved by combination of these forms of treatment:
Anti-thyroid medications (methimazole and Propylthiouracil) – prevent thyroid hormone synthesis and release
Medications called Beta-blockers to control the heart rate and prevent further activation of thyroid hormones
Radioactive iodine – destroys and renders the thyroid gland inactive
Surgery to remove the thyroid gland
A successful treatment of hyperthyroidism most of the time results in a normal functioning or an underactive thyroid (hypothyroidism). The last two options on the list are definitive treatments that have a faster result. At the time of diagnosis there is an option of either medications (anti-thyroid medication + Beta-blocker) vs. Radioactive iodine ablation vs. surgery. The decision on which treatment option to take is a shared decision making process between you and your treating physician after reviewing the pros and cons of each. For women considering pregnancy its recommended not to have radioactive iodine ablation at least 12 months before pregnancy and during breastfeeding, therefore medication or surgery might be a better option for those planning to conceive.
