Kidney, Liver, and Thyroid Health

What could be affecting my thyroid health?

What is the thyroid gland?
The thyroid gland is a small organ located just under the skin in the neck. This bow tie-shaped organ is usually only about 5 cm across and normally can’t be felt or seen. The thyroid releases specific hormones (chemical messengers) that act on almost every tissue in the body (1). These thyroid hormones help regulate so many vital body functions, including:

  • Heart rate
  • Skin maintenance
  • Heat production
  • Fertility
  • Growth
  • Digestion
  • Rate at which calories are burned

What happens when the thyroid isn’t functioning properly?
Thyroid hormones influence so many different parts of the body, so when they are out of balance, lots of different symptoms can occur.

Hypothyroidism is an underactive thyroid, so it does not release enough thyroid hormones. This causes many of the body’s functions to slow down, causing symptoms like fatigue, slow heart rate, constipation, weight gain, and constantly feeling cold (2).

Hyperthyroidism is an overactive thyroid, so too many thyroid hormones are released into the bloodstream. This speeds up many of the body’s functions, causing symptoms like weight loss (even though appetite is increased), rapid or irregular heart rate, frequent bowel movements, sweating, and shaky hands (3).

What are the possible causes of hypothyroidism?
An underactive thyroid is quite common, affecting nearly 5 out of 100 Americans 12 years and older, although many are only minimally affected (2). The causes of hypothyroidism include:

Hashimoto’s disease. An autoimmune disorder where your own immune system attacks the thyroid. This is the most common cause of hypothyroidism.

Thyroiditis. Inflammation of the thyroid can cause thyroid hormones to leak out (and initially increase the levels in the blood) until the thyroid eventually becomes underactive. Thyroiditis can be one of three different types:

  • Subacute thyroiditis (painfully inflamed and enlarged)
  • Postpartum thyroiditis (after pregnancy)
  • Silent thyroiditis (painless and maybe from an autoimmune condition)

Congenital hypothyroidism. Some infants are born with a thyroid that is not fully developed or not fully functional. Prompt treatment is important to prevent intellectual disability and growth failure.

Removal of part or all of the thyroid or radiation treatment of the thyroid, head, or neck. These may occur as a treatment for hyperthyroidism, large goiter, thyroid nodules, or thyroid cancers.

Medications. Certain medications can interfere with thyroid function, including some heart, bipolar, and cancer medicines.

Who is at increased risk of hypothyroidism?

  • Women, particularly if had a child within the previous 6 months
  • People over 60 years
  • People with previous thyroid issues or a family history of thyroid issues
  • Diabetics
  • People affected by certain autoimmune conditions, including celiac disease, rheumatoid arthritis, and lupus

What are the possible causes of hyperthyroidism?
Hyperthyroidism (overactive thyroid) is less common than hypothyroidism, affecting about 1 out of 100 Americans 12 years and older (3). The causes of hyperthyroidism include:

Graves’ disease. An autoimmune disorder where your own immune system attacks the thyroid causing it to make too many hormones. This is the most common cause of hyperthyroidism.

Overactive thyroid nodules. Noncancerous lumps in the thyroid that produce too many thyroid hormones.

Thyroiditis. Inflammation of the thyroid can cause thyroid hormones to leak out and increase the levels in the blood. In some cases, thyroiditis can eventually cause the thyroid to become underactive and cause hypothyroidism. Thyroiditis can be one of three different types:

  • Subacute thyroiditis (painfully inflamed and enlarged)
  • Postpartum thyroiditis (after pregnancy)
  • Silent thyroiditis (painless and maybe from an autoimmune condition)

Excess iodine. Iodine is required to make thyroid hormones, so consuming too much iodine (either through foods (e.g., kelp), supplements, or medicines) can result in hyperthyroidism.

Excess thyroid medication. This may occur in people suffering from hypothyroidism who take too much of their thyroid medication, as the amount required may differ over time.

Noncancerous tumors of the pituitary gland. The pituitary gland releases thyroid-stimulating hormone (TSH), which signals for the thyroid to produce hormones, so issues with the pituitary function can also affect thyroid function.

Who is at increased risk of hyperthyroidism?

  • Women, particularly if had a child within the previous 6 months
  • People over 60 years
  • People with previous thyroid issues or a family history of thyroid issues
  • People affected by other health problems, including diabetes, primary adrenal insufficiency (hormone disorder), and pernicious anemia (caused by vitamin B12 deficiency)
  • People who eat large amounts of food containing iodine (e.g., kelp) or take medicines with iodine

References:
1. Hershnan JM. (Modified Oct 2020). Overview of the Thyroid Gland. Merck Manual Consumer Version
2. Hypothyroidism (Underactive Thyroid). National Institute of Diabetes and Digestive Kidney Diseases. NIH. Reviewed March 2021.
3. Hyperthyroidism (Overactive Thyroid). National Institute of Diabetes and Digestive Kidney Diseases. NIH. Reviewed August 2021.