Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at June 30, 2016

Hypothyroidism is a deficiency in the production of thyroid hormone which regulates the rate of metabolism. When too few of the thyroid hormones are produced, complications can result.


Definitions & Facts

The thyroid is an endocrine gland located in the front neck near the Adam’s apple. It is in constant communication with the pituitary gland and hypothalamus. Together they regulate heart rate, breathing, hormonal cycles, menstrual cycles, energy level, body temperature, and body weight.

The thyroid produces two type of hormones, known together as thyroid hormone: thyroxine (T3) and triiodothyronine (T4). If hormone levels change, either by becoming too high (hyperthyroidism) or too low, the thyroid can change the rate of metabolism with a range of metabolic effects. Hypothyroidism affects more women than men.

Symptoms & Complaints

Symptoms of hypothyroidism range from weight gain, rough and dry skin, hair loss, and irregular menstrual cycle to general feelings of depression, fatigue, weakness, and irritability. Some experience bloating and a feeling of nausea, while others have headaches and mental fog.

If hypothyroidism goes untreated for extended periods of time, growths such as goiters, nodes, or enlarged and inflamed glands can form which can be visible.


Iodine deficiency is a major cause of hypothyroidism. In order to produce the thyroid hormones T3 and T4, the thyroid gland needs the correct amount of iodine introduced into the blood stream. Iodine is consumed through food so populations in countries where iodine is not a component of the diet are at risk for developing hypothyroidism.

Another cause of hypothyroidism unrelated to iodine intake is Hashimoto's thyroiditis in which the immune system attacks the thyroid, causing inflammation and the reduced production of thyroid hormone.

A less common cause of hypothyroidism is the deficiency of thyroid-stimulating hormone (TSH). TSH is secreted by the pituitary gland and controls the process by which the thyroid creates T3 and T4 hormones. Deficiencies of TSH can be caused by disorders of the hypothalamus and pituitary gland.

The pituitary and thyroid glands can sometimes be injured, inflamed, or thrown off balance by injuries, tumors, hormonal imbalances in other areas of the body, or surgeries and radiation for thyroid cancer. Any attack or damage to these glands can cause hypothyroidism to form.

Hypothyroidism can also be congenital and caused by genetic mutations. If left untreated among babies, it can result in intellectual disabilities and physical disabilities.

Diagnosis & Tests

The diagnostic process begins with doctors first analyzing symptoms and family history surrounding thyroid hormones and glands. Doctors can then proceed to physically examine the thyroid gland for inflammation or growths as well as perform blood tests in order to detect hormonal imbalances. Thyroid-stimulating hormone tests (TSH) is a test that can be administered to determine iodine levels and T3 and T4 hormones. Hormone level tests can sometimes be an unreliable indicator of hypothyroidism for women, as levels are continually up and down due to menstruation cycles and other metabolic activities.

Treatment & Therapy

Synthetic thyroid hormone, levothyroxine is commonly prescribed to restore hormone levels and reverse the symptoms of hypothyroidism. The goal for any sort of treatment for hypothyroidism is to keep iodine, T3 and T4 levels in their normal range. While hypothyroidism is more prevalent in adults, infants may be born with the condition, requiring much more attention to hormone doses and side effects.

Prevention and Prophylaxis

Various public health initiatives have caused the addition of iodine into salt used in food consumption as a means of preventing hypothyroidism and goiter. Because hypothyroidism can have severe consequences for childbirth and the developing child, iodine supplements are recommended for pregnant women.