Bringing the Thyroid Up to Speed
What is hypothyroidism?
Hypothyroidism, more commonly known as an "underactive thyroid" is a condition in which the person doesn't make enough thyroid hormones, which controls how the body uses and stores energy. There are various reasons why this occurs, but the most common cause is called Hashimoto's thyroiditis. This is an autoimmune disease, in which the immune system turns against the body's thyroid gland causing it to produce fewer hormones over time. The exact cause of why it develops is currently unknown. There are risk factors, which increases the chance of developing thyroiditis, such as sex, age, heredity, and presence of other autoimmune diseases such as rheumatoid arthritis, type I diabetes or lupus. Women get it more than men. It can occur at any age, but most commonly during middle age.
What are the symptoms of hypothyroidism?
The symptoms of an underactive thyroid can be nonspecific and may include fatigue, constipation, dry skin, increased sensitivity to cold, unexplained weight gain, muscle and joint pain, menstrual irregularities, and depression. It can also cause low sodium levels in the blood, as well as contribute to elevated cholesterol. Untreated long-term hypothyroidism can also lead to a rare but serious complication called myxedema, which can present as intense cold intolerance, drowsiness, and subsequently severe lethargy and unconsciousness. This is usually triggered by stress on the body, such as infections, in the setting of untreated, long-term hypothyroidism.
How is hypothyroidism diagnosed?
Diagnosis of hypothyroidism can be made by obtaining blood work, specifically thyroid stimulating hormone (TSH), and free T4. TSH is a hormone produced by the pituitary gland to stimulate the thyroid to produce thyroid hormones. T4 is one of the thyroid hormones secreted by the thyroid gland. In hypothyroidism, the level of thyroid hormone (T4) is low and because the pituitary gland is trying to stimulate increased production of T4, TSH will be higher than normal. You can also be tested for thyroid antibodies, which may be elevated in thyroiditis. Testing for thyroid abnormalities is usually done for people who have symptoms as outlined above, as well as for screening, especially people who are at an increased risk for developing hypothyroidism.
Treatment for hypothyroidism includes various formulations of the thyroid hormone. The most commonly used medication is levothyroxine, which is a T4 thyroid hormone. Combinations of T3 (another thyroid hormone) and T4 as well as T3 alone are also available. T3/T4 formulations have not been shown to be superior to T4 alone. It is not recommended to treat hypothyroidism with only a T3 hormone. Thyroid medications should be taken on an empty stomach, ideally at least an hour before breakfast.
People treated for hypothyroidism usually feel an improvement after two weeks, but it can take several months to completely recover especially in severe cases. Blood tests, most commonly TSH, are used to assess the adequacy of thyroid replacement. Because it takes several weeks for the TSH concentration in the blood to achieve a steady state, it is recommended to wait approximately four to six weeks before checking TSH levels after initiation of medication or change in dose. The dose of medication that results in normal TSH levels, as well as improvement of symptoms, would be the maintenance dose.
Once a maintenance dose has been achieved, periodic testing is done yearly or more often if there are changes in symptoms or if there is an abnormal labwork result. As with any medical condition, it is important to take the medication regularly, as well as maintain a healthy diet and regular exercise.
Northern Dutchess Hospital
Health Quest Medical Practice, P.C.
6511 Springbrook Park, Suite 1001
Rhinebeck, NY 12572
TTY /Accessibility: (800) 421-1220
Read Past Topics from Dr. Abis:
Take a Step in the Right Direction to Treat Diabetes