Thyroid, an organ that influences your metabolism

The thyroid is a butterfly-shaped organ located near the throat in front of the neck region. It is a gland that produces chemicals called hormones that play a vital role in regulating body metabolism, blood pressure, heart rate, etc, as part of the endocrine system. The two main hormones that produce are Thyroxine (aka T4) and Triiodothyronine (aka T3). It uses iodine as a substrate to produce these vital hormones. T4 is the primary hormone that emits by the gland, a small portion is converted to triiodothyronine (T3) once it is released into the blood and tissues. T3 is the more active hormone.

Other important determinant functions are TSH or Thyroid Stimulating Hormone and the proteins (Thyroglobulin) which carry the hormones in the blood and convey them to the tissues that utilize them. Changes in both these substances have an effect on the function along with any other problems that are intrinsic to the thyroid gland itself.

TSH is a hormone released by the pituitary gland located near the hypothalamus in the brain. TSH stimulates the thyroid gland to release more T4 & T3. It has a feedback loop and the amount of TSH in the blood is determined by the number of thyroid hormones in the blood. An increase in thyroxine levels leads to a decrease in TSH levels or vice versa. TSH is one of the most sensitive and earliest markers to diagnose thyroid problems.

Since the thyroid hormones require proteins for transportation to the end organs, conditions that result in protein deficiency can affect the activity of the gland. To confirm thyroid abnormality monitor these conditions every time.

Health problems related to the thyroid gland are a result of either the under-activity or the over-activity of the thyroid gland, conditions known as Hypothyroidism and Hyperthyroidism respectively.

Underactive thyroid (Hypothyroidism)

Deficiency in hormones leads to a slowing down of metabolism and other vital functions in the body. Symptoms can include:

  1. Increased sensitivity to cold
  2. constipation
  3. depression
  4. fatigue
  5. heavier menstrual flow
  6. brittle hair and nails

If left untreated, severe hypothyroidism can cause obesity, joint pain, heart disease, infertility, and in very severe cases coma and death. Symptoms of severe hypothyroidism can include:

  1. hoarseness
  2. puffiness of the face, hands, and feet
  3. slowed speech
  4. decreased taste and smell
  5. thin eyebrows
  6. thickened skin

Treatment of hypothyroidism would include identifying and correcting the underlying cause and replacing thyroxine (T4) with a synthetic hormone.

Also, Read – Stress and Thyroid: Interrelation

Overactive thyroid (Hyperthyroidism)

High amounts of T4, T3, or both can cause an excessively high metabolic rate, a condition known as a hypermetabolic state. Symptoms may include a rapid heart rate, elevated blood pressure, hand tremors, excessive sweating, and a low tolerance for heat. Hyperthyroidism can cause more frequent bowel movements, weight loss, and, in women, irregular menstrual cycles.

Hyperthyroidism goes with a swelling itself, a condition known as a goiter, which can be symmetrical. In graves disease, which is a diffuse swelling of the thyroid gland due to an abnormality in the auto-immune system, the eyes may also appear quite prominent,  a sign called exophthalmos.

Other symptoms of hyperthyroidism include:

  1. irregular heartbeat
  2. difficulty sleeping
  3. fine, brittle hair
  4. itching
  5. hair loss
  6. nausea and vomiting
  7. breast development in men
  8. increased appetite
  9. nervousness
  10. restlessness
  11. inability to concentrate

Medical attention is necessary if you have these symptoms:

  1. dizziness
  2. shortness of breath
  3. loss of consciousness
  4. fast, irregular heart rate

Treatment of hyperthyroidism is specific to the underlying cause of the condition and may include Anti-thyroid medications, such as methimazole, radioactive iodine, or surgery.

Written by MedPlus