It’s shaped like a butterfly and weighs just an ounce, but regardless of its innocuous appearance, the thyroid gland wields considerable power over important biological functions. Metabolism, growth and the regulation of blood calcium levels are all strongly influenced by the thyroid gland.
Thyroid gland dysfunction can disrupt the production of thyroxine, triiodothyronine and calcitonin, three hormones that are essential to good health.
Causes
The thyroid can be affected by genetic disorders, autoimmune reactions, inflammation, dietary iodine deficiency and exposure to drugs or toxins, according to the University of Maryland Medical Center.
The autoimmune conditions known as Graves’ disease and Hashimoto’s thyroiditis cause increases or decreases of thyroid hormone levels, respectively. These conditions are both suspected to have genetic components that predispose a vulnerability to fall prey to their effects. A diet deficient in iodine depletes the body of an ingredient that is essential in the production of thyroid hormone. Inflammation of the thyroid can impair its ability to function properly.
Effects
The thyroid’s influence on metabolism is reflected in the symptoms of conditions in which thyroid hormone levels are altered abnormally. Hypothyroid disorders, wherein thyroid hormones are decreased, typically cause fatigue, constipation and intolerance to cold. Hyperthyroidism occurs when excessive thyroid hormone is produced. This condition commonly manifests in symptoms such as weight loss, accelerated heart rate and heat intolerance.
Diagnosis
The diagnosis of thyroid disorders involves patient interviews by the doctor to determine what current symptoms the patient is experiencing and whether a personal or family history of thyroid disorders exists. A physical exam will be conducted to evaluate the size of the thyroid gland, heart rate, reflexes and skin changes. Blood tests that evaluate thyroid hormone levels are commonly conducted. The American Thyroid Association adds that a thyroid scan can provide the doctor with a picture of the thyroid that will aid in discerning the presence of inflammation or toxic nodules.
Treatment
An overactive thyroid is sometimes treated with antithyroid medications to suppress the excessive production of hormones. Treatments involving radioactive iodine offer a more permanent solution by destroying thyroid tissue. Surgical treatment options exist as well. Removal of part of the thyroid gland can reduce the production of thyroid hormone, while complete thyroid removal eliminates the production of these hormones entirely
For under-active thyroid glands, supplementation with synthetic thyroid hormone pills is the most commonly used form of treatment, according to the Merck Manuals Online Medical Library.
Prognosis
Thyroid replacement hormones are effective in relieving the effects of hypothyroidism, but they do not cure the disorder. Synthetic thyroid pills must be taken as an ongoing method of managing symptoms throughout the patient’s life.
Antithyroid drugs will provide some relief from hyperthyroidism, but are not a cure for the disorder. High hormone levels will return when the use of medication ceases. Surgery and radioactive iodine treatments effectively address the causes of hyperthyroidism, and cure that condition, but often lead to a depletion of thyroid hormones that necessitates lifelong supplementation with synthetic thyroid hormone.
