Proper levels of thyroid hormones are critically important for metabolism and neurological function.  The hypothalamus (an areas of the brain) measures blood thyroid levels and if low sends a chemical messenger (TSH) to the thyroid gland instructing it to make more thyroid hormone.  There are two thyroid hormones, T3 (the most active) and T4 (relatively inactive).  The body converts the relatively inactive T4 into T3 - which is very active. Under stress the body produces reverse T3, which lowers the effective thyroid blood levels.   Thyroid function can be monitored with blood tests.

Children born without thyroid hormones develop “cretinism” - a syndrome of severe growth and mental retardation which is totally preventable by taking thyroid hormone pill.  Symptoms of low thyroid (hypothyroidism) can include fatigue, numbness and tingling, reduced memory and concentration, constipation, goiter (thyroid enlargement) weight gain (even with diet and exercise), dry skin, puffiness around the eyes, hair loss, coarse hair, slow heart rate, high cholesterol, fluid retention, PMS, cold intolerance, orange skin color, large tongue, hoarseness, low body temperature, loss of “lateral eyebrows”, anemia, depression, personality changes, seizures and eventually coma and death.

Some people have high amounts of thyroid hormone (hyperthyroidism).  Symptoms of hyperthyroidism include tremors, shakes, unexplained weight loss, palpitations, nervousness, sweating, excessive energy, heat intolerance, frequent bowel movements, insomnia, weakness, thin hair, increased appetite, and warm moist skin.  Hyperthyroidism can trigger the dangerous heart rhythm “atrial fibrillation,” which can cause strokes.

Some people have nodules or masses on their thyroid gland.  They are usually found on ultrasound or a CT scan of the chest or neck.  Sometimes a biopsy is necessary to rule out cancer.

The blood tests can measure T4, T3 and TSH.  The T4 and T3 should be normal.  If they are low the TSH will rise.  The TSH is the opposite - the higher the number the lower the thyroid.  With hypothyroidism the TSH will be high (preferably more than 10), with hyperthyroidism the TSH is low.  Some patients can have the T3, T4 and TSH all low - this is due to “non primary hypothyroidism.”  Instead of following the TSH, the T3&T4 need to be kept in the normal range in these patients.  Non primary hypothyroidism can be seen in depression, BPD (borderline personality disorder), panic disorder, bulimia, alcoholism (in remission) and anorexia nervosa. 

Thyroid cancer is uncommon.  Once the treatment is completed,  the goal is to keep the TSH suppressed.  The blood test thyroglobulin can monitor some thyroid cancers.

Treatment of hypothyroidism is with T4 (Synthroid, Levoxyl, levothroid), monitoring the blood levels regularly.  Thyroid “extract” is obtained from chopped up animal thyroid glands.  The most common one is “Armour thyroid” which has both T3 and T4 in it.  Rarely patients need to take the very active T3 - it is difficult to monitor.