Thyroid Disease

Thyroid Disease

Thyroid disease is a medical condition that affects the function of the thyroid. The thyroid gland is one of the largest glands in the endocrine system and is located in the neck. The thyroid cells absorb the iodine and convert it into two hormones; thyroxine (T4) and triiodothyronine (T3) which help control the body’s metabolism. The pituitary gland, which is located at the bottom of the brain, controls the thyroid gland. As the different levels of T3 and T4 become very low, the Thyroid Stimulating Hormone (TSH) is released from the pituitary gland to help increase the amount of T3 and T4 hormones. Once the levels of T3 and T4 are equal, the TSH will stop being produced.

There are two main types of thyroid diseases:

  • Hyperthyroidism occurs when the thyroid gland produces an increased amount of the hormones T3 and T4.
  • Hypothyroidism occurs when the thyroid gland doesn’t produce enough of the T3 & T4 hormones.
Thyroid testing


When the thyroid gland is overactive, hyperthyroidism, it releases too much of its hormones T3 & T4. Hyperthyroidism only affects approximately 1 percent of women and is even less common in men.

Causes of hyperthyroidism

There are multiple causes of Hyperthyroidism, Graves’ disease accounts for 70% of the affected. Other possible causes are thyroid inflammation or nodules on the thyroid, also called toxic nodular goiter or multinodular goiter.

Symptoms of excessive thyroid hormone:

  • restlessness
  • nervousness
  • racing heart
  • irritability
  • increased sweating
  • shaking
  • anxiety
  • trouble sleeping
  • thin skin
  • brittle hair and nails
  • muscle weakness
  • weight loss
  • bulging eyes (in Graves’ disease)

Hyperthyroidism diagnosis and treatment

A blood test is available to measure the levels of thyroid hormone (thyroxine, or T4) and thyroid-stimulating hormone (TSH) in your blood. Because the pituitary gland releases TSH to stimulate the thyroid to produce T3 & T4. When high thyroxine (produced by the thyroid) and low TSH (produced by the pituitary gland) levels are recorded it is an indication that your thyroid gland is overactive.


Hypothyroidism is the opposite of hyperthyroidism. The thyroid gland is underactive, and it can’t produce enough of the hormones T3 & T4.

Causes of Hypothyroidism

Hypothyroidism is often caused by Hashimoto’s disease, surgery to remove the thyroid gland, or damage from radiation treatment or other medications, abnormal growths on the thyroid, or disfunction in the pituitary gland.

Symptoms of deficient thyroid hormones:

  • fatigue
  • dry skin
  • increased sensitivity to cold
  • memory problems
  • constipation
  • depression
  • weight gain
  • weakness
  • slow heart rate
  • coma

Hypothyroidism diagnosis and treatment

The blood tests used to measure your TSH and thyroid hormone levels are also effective for diagnosing hypothyroidism. A high TSH (produced by the pituitary) level and low thyroxine (produced by the thyroid) level indicates that your thyroid is underactive. These levels could also indicate that your pituitary gland is releasing more TSH in an attempt to stimulate the thyroid gland.