Hypothyroidism can affect your quality of life in far more subtle ways than you can think. Although it is common to ignore signs such as fatigue, dry skin, weight gain or joint ache and blame it on your lifestyle — we often underestimate the importance of thyroid on our normal functioning.
Luckily, underactive thyroid or hypothyroidism can be completely managed with medications and over time the severity of your symptoms can be reduced. However, before you start with your treatment regimen, it is important to understand the many causes of hypothyroidism. But before we list down the causes, let’s first understand how your thyroid gland works.
How does the thyroid function?
Thyroid is a gland — which means it is an organ that produces and releases certain substances such as hormones that control specific functions. Thyroid produces two hormones called thyroxine also called T4 and small amounts of another hormone called triiodothyroxine or T3.
T3 is the active form of thyroxine that regulates various body functions such as metabolism, body temperature, heart rate and blood pressure. However, most of the T3 that is produced is converted from T4 and the rest is produced in small amounts directly from the thyroid.
Since thyroxine plays an important role in many body processes, its production needs to be controlled. The pituitary gland which is situated at the base of your brain secretes a hormone called thyroid-stimulating hormone (TSH) which sends signals to the thyroid gland to stimulate production of thyroxine. When your doctor prescribes you to get a blood test done to check thyroid function, usually it is to measure your TSH levels.
What causes hypothyroidism?
Given the complexity of how the thyroid gland functions, it’s not surprising to imagine that something could go wrong with the thyroid functioning. In general, thyroid disorders such as underactive thyroid can either be due to an underlying condition, changes to the the thyroid gland itself or certain medication that can affect its function.
1. Autoimmune disorders
Think of your immune system as the front-line soldiers of your body. They protect you from foreign invaders, which biologically means pathogens such as bacteria and viruses. But sometimes your immune system can malfunction and attack your own body parts instead of foreign substances. Such conditions are known as autoimmune (auto meaning self) disorder. One such autoimmune disorder is called Hashimoto’s disease, where the immune system accidentally attacks the thyroid. This can cause the cells to be damaged and affect its ability to produce sufficient thyroxine. When enough thyroid cells have been damaged, very few are left to meet the body’s requirement for thyroxine resulting in hypothyroidism.
Thyroiditis simply means inflammation of the thyroid which can happen either due to an autoimmune attack, virus or certain medications. When this happens, the stored thyroid hormone gets leaked out into the blood and for a brief period of time there will be very high levels of thyroid hormones. Once the entire stored hormone has been released, the damaged thyroid is unable to make any more hormones and becomes underactive. Most people with thyroiditis recover their thyroid function, but some might end up having permanent hypothyroidism.
3. Radiation treatment
Some people who have Graves’ disease (an autoimmune disorder that causes overactive thyroid) or thyroid cancer are treated with radioactive iodine which gradually destroys the thyroid cells. This affects the ability of the thyroid gland to produce hormones and might eventually lead to hypothyroidism. Even cancers of the head and neck which require radiation therapy might also damage the thyroid.
4. Surgical removal of a part or all of thyroid
Certain conditions such as hyperthyroidism, thyroid cancer or thyroid nodules might require surgical removal of a part of a thyroid. When this happens, the remaining part of the thyroid may continue to produce normal amounts of the thyroid hormone but some people may develop hypothyroidism. Incase of removal of the entire thyroid, it always results in hypothyroidism.
Certain medications have the ability to interfere with thyroid function which can affect the production of thyroid hormones. Some medications prescribed for heart problems, bipolar disorder and cancer treatment are known to have an effect on the thyroid.
6. Congenital (from birth) hypothyroidism
Some babies are born with a thyroid that is either not fully developed or does not function properly. If left untreated, congenital hypothyroidism can lead to complications in adult life and also affect growth.
Early diagnosis of hypothyroidism by testing newborn babies, pregnant women and people who have certain risk factors such as family history is the best way to prevent hypothyroidism from worsening. Many people are diagnosed with hypothyroidism after years of showing symptoms that are often ignored by labelling it as either stress or a normal part of aging. So it is a relief for some people to finally know what the reason was and now have a clear treatment plan to start feeling better. If you are unsure of your symptoms it is always advised to see a doctor who can find out if the root cause is hypothyroidism or any other underlying condition.
Learn More with Veera Health
Hypothyroidism can cause symptoms similar to PCOS. If you are not sure what your unexplained symptoms could mean, take our free PCOS screening quiz to understand your risk levels.
Disclaimer: Content on Veera is provided for informational purposes only and is not intended as medical advice, or as a substitute for medical advice given by a physician