Thyroid Disorders

Overview

Through the hormones it produces, the thyroid gland influences almost all of the metabolic processes in your body. Thyroid disorders can range from a small, harmless goiter (enlarged gland) that needs no treatment to life-threatening cancer. The most common thyroid problems involve abnormal production of thyroid hormones. Too much thyroid hormone results in a condition known as hyperthyroidism. Insufficient hormone production leads to hypothyroidism.Although the effects can be unpleasant or uncomfortable, most thyroid problems can be managed well if properly diagnosed and treated.

What Causes Thyroid Problems?

All types of hyperthyroidism are due to an overproduction of thyroid hormones, but the condition can occur in several ways:

• Graves' disease: The production of too much thyroid hormone.
• Toxic adenomas:Nodules develop in the thyroid gland and begin to secrete thyroid hormones, upsetting the body's chemical balance; some goiters may contain several of these nodules.
• Subacute thyroiditis:Inflammation of the thyroid that causes the gland to "leak" excess hormones, resulting in temporary hyperthyroidism that generally lasts a few weeks but may persist for months.
• Pituitary gland malfunctions or cancerous growths in the thyroid gland:Although rare, hyperthyroidism can also develop from these causes.

Hypothyroidism,by contrast, stems from an underproduction of thyroid hormones. Since your body's energy production requires certain amounts of thyroid hormones, a drop in hormone production leads to lower energy levels. Causes of hypothyroidism include:

• Hashimoto's thyroiditis:In this autoimmune disorder, the body attacks thyroid tissue. The tissue eventually dies and stops producing hormones.
• Removal of the thyroid gland:The thyroid may have been surgically removed or chemically destroyed.
• Exposure to excessive amounts of iodide:Cold and sinus medicines, the heart medicine amiodarone, or certain contrast dyes given before some X-rays may expose you to too much iodine.You may be at greater risk for developing hypothyroidism if you have had thyroid problems in the past.
• Lithium: This drug has also been implicated as a cause of hypothyroidism.

Untreated for long periods of time, hypothyroidism can bring on a myxedema coma, a rare but potentially fatal condition that requires immediate hormone treatment.

Hypothyroidism poses a special danger to newborns and infants. A lack of thyroid hormones in the system at an early age can lead to the development of cretinism (intellectual disability) and dwarfism (stunted growth). Most infants now have their thyroid levels checked routinely soon after birth. If they are hypothyroid, treatment begins immediately. In infants, as in adults, hypothyroidism can be due to these causes:

• A pituitary disorder
• A defective thyroid
• Lack of the gland entirely

A hypothyroid infant is unusually inactive and quiet, has a poor appetite, and sleeps for excessively long periods of time.

Cancer of the thyroid gland is quite rare and occurs in about 5% of thyroid nodules. You might have one or more thyroid nodules for several years before they are determined to be cancerous. People who have received radiation treatment to the head and neck earlier in life, possibly as a remedy for acne, tend to have a higher-than-normal risk of developing thyroid cancer.