Hypothyroidism: What is it, do I have it, and how is it treated?

What does the thyroid gland do?

The thyroid gland is an endocrine gland located at the base of your neck that regulates metabolism or how your body uses energy, which in turn affects breathing, heart rate, body weight, menstrual cycles, body temperature, cholesterol levels, and other functions. This gland uses iodine from the foods we eat to form triiodothyronine (T3) and thyroxine (T4). The hypothalamus in the brain senses how much T3 and T4 is in the blood:

• When levels of T3/T4 are low, the hypothalamus secretes thyroid-releasing hormone (TRH) to stimulate the pituitary gland to release thyroid stimulating hormone (TSH), which then stimulates the thyroid gland to produce more T3 and T4 in a ratio of approximately 1:4.
• When levels of T3/T4 are high, the hypothalamus stops secreting TRH to inhibit the pituitary gland from releasing TSH, reducing T3 and T4 production by the thyroid gland.

T4 is considered a prohormone because it is not active and needs to be converted to T3 by enzymes called type 1 and type 2 deiodinases (D1 and D2). D1 is expressed in the liver and kidneys, while D2 is found in the central nervous system, pituitary gland, and other tissues.

What causes hypothyroidism?

Women are much more likely to have hypothyroidism, and its incidence increases with age. Causes include:

• Hashimoto’s disease, an autoimmune disorder.
• Thyroiditis, inflammation of the thyroid gland.
• Surgical removal of the thyroid gland.
• Radiation treatment to the neck or thyroid gland.
• Certain medications like amiodarone and lithium.
• Damage to the pituitary gland.

What are the signs and symptoms of hypothyroidism?

• Fatigue
• Trouble sleeping
• Difficulty concentrating
• Dry skin and hair
• Depressed mood
• Cold sensitivity
• Irregular or heavy periods
• Joint and muscle pain
• Weight gain
• Myxedema

How do I know if I have hypothyroidism?

Hypothyroidism is diagnosed based on lab values: high TSH and normal/low T4. Symptoms alone are not sufficient for diagnosis but are monitored during treatment.

Read more: Thyroid Function Tests

What treatments are available for hypothyroidism?

Levothyroxine, a synthetic T4, is the first-line treatment due to its efficacy and safety profile. The goals of treatment are:

1. Resolution of symptoms
2. Normalization of TSH and T4 levels
3. Avoidance of overtreatment

Natural thyroid medications like NP thyroid and Armour thyroid are not recommended as first-line therapy. Combined preparations may benefit patients with impaired T4-to-T3 conversion.

Read the guidelines: Guidelines for the Treatment of Hypothyroidism

Since iodine is needed to make T3 and T4, should I use iodine supplements?

The U.S. population is iodine sufficient, and excessive supplementation can disrupt thyroid function. At-risk populations include:

• People who do not use iodized salt
• Pregnant women
• Vegans or those with limited dairy/seafood intake

Read more: Iodine in the U.S. Population

Summary

The thyroid gland regulates metabolic activity. Hypothyroidism, characterized by insufficient thyroid hormone, is diagnosed via lab tests and treated with medications like levothyroxine.

If you suspect hypothyroidism, call 434-260-1667 or contact us.