Healthy Living

What Causes Hypothyroidism?

What Causes Hypothyroidism?

Hypothyroidism is a type of hormonal imbalance in which the thyroid hormones are in lower than normal. Essentially, it is the result of an underactive thyroid, and may be referred to as such. The two major hormones produced by the thyroid gland (T3 and T4) play an important role in your metabolism and production of energy. Low levels of these hormones affect the temperature of the body, heart rate, and body weight. Most patients with this condition suffer from excessive fatigue and exhaustion. The afflicted tends to gain weight, even when they engages in moderate physical activities regularly. Other symptoms may include dry skin, constipation, and sensitivity to cold. This condition is very common, affecting almost three million people in the United States alone each year.

Have a question aboutHypothyroidism?Ask a doctor now


There are many causative factors for hypothyroidism or lower activity of thyroid glands. However, one should never jump to a conclusion of having hypothyroidism without first consulting a doctor and receiving a proper diagnosis. Possible causes of hypothyroidism include:

Hashimoto’s Disease – This disease is also referred to as chronic lymphyocytic thyroiditis. This is a condition characterized by impaired immune activity where the immune system attacks and destroys thyroid gland tissues. The reason for this abnormal behavior of immune system is still not clear. Hashimoto’s disease is one of the most common causes of hypothyroidism as the affected thyroid gland fails to produce enough hormones. It is treatable, but requires a medical diagnosis. Lab tests and imaging will most probably be required in order to definitively diagnose this condition. Unfortunately, the condition is chronic, lasting years or potentially the afflicted's whole lifetime. The most obvious symptoms are fatigue and sudden weight gain. Effective treatments include synthetic hormone medications.

Thyroidectomy – People suffering from thyroid nodules, thyroid cancer, or Graves' disease quite often need to have part or all of their thyroid removed through a surgery called a thyroidectomy. The production of hormones by the thyroid gland is affected by both a partial and complete removal of the glands. Total removal of glands, called as total thyroidectomy, leads to symptoms of hypothyroidism. Partial removal also affects the amount of hormones produced by the glands. This may cause hypothyroidism in about half the people undergoing partial thyroidectomy. Using anti-thyroid drugs for diseases can reduce the production of hormones by thyroid glands. Hormone replacement therapy is suggested in both the cases of thyroid removal so as to maintain hormone levels. If part of the gland is left, there may be just enough to continue adequate functioning of the thyroid.

Treatment for Overactive Thyroids – An overactive thyroid or hyperthyroidism results in excess production of hormones. Treatment for hyperthyroidism often affects the glands and reduces the hormone levels to below normal. This can be controlled by regular assessment of thyroid hormone levels in body. There have been cases where hyperthyroidism resulted in permanent reduction of thyroid hormones. 

Radiation Treatment – There is a concern for the correlation between radiation treatment and hypothyroidism. The treatment of cancers - particularly of neck region, Hodgkin's disease, and lymphoma - by radiation therapy may lead to hypothyroidism. These patients are treated with radioactive iodine and may lose all functioning of their thyroid.

Medications – Certain drugs are known to impair the function of thyroid glands and lead to reduced production of thyroid hormones. This is particularly true of certain medications used in cardiovascular and psychotic diseases.  Some common examples of medications that cause hypothyroidism are amiodarone, interleukins and interferon-α. These drugs may trigger hypothyroidism in patients with a genetic predisposition to autoimmune diseases.

Inherited Diseases – Certain inherited conditions lead to the birth of children with impaired thyroid glands. Although it is rare, children are sometimes born without a complete set of glands. This is called congenital hypothyroidism. Symptoms of this condition are not often obvious at birth, but gradually become severe as the child gets older. In another rare case, the thyroid may be born in the wrong place, in a condition known as ah ectopic thyroid.

Disorders of the Pituitary Gland – The pituitary gland is the major endocrine gland of the body. It is sometimes called 'the master gland'. It is attached to the base of the brain and is responsible for controlling growth and development of the other endocrine glands. Disorders affecting the pituitary gland in the brain affects the production of the thyroid stimulating hormone (TSH). TSH plays a role in stimulating the thyroid gland for the production of hormones. Thus, reduced TSH lowers the amount of hormone released from thyroid glands. The pitiuitary gland may also be damaged physically: a tumor, radiation, or surgery can all affect the pituitary gland, rendering it unable to accurately direct the thyroid, causing it to make an inadequate amount of hormone.

Pregnancy – In some cases, pregnant women may develop antibodies against the tissues of the thyroid gland. This can happen either during her pregnancy term or after delivery. In both conditions, the glands are affected and result in hypothyroidism. When left untreated, hypothyroidism during pregnancy causes pre-term birth and hypertension.

Nutritional Deficiencies – Certain minerals, especially iodine, are very important in the synthesis of thyroid hormones in the body. Low amounts of iodine in the diet can lead to hypothyroidism. Consuming a diet with adequate amounts of protein is vital, as it is a major factor in producing normal amounts of TSH. Every thyroid patient should monitor their nutritional levels carefully. Giving regular blood tests is a good way to monitor your nutritional levels even if you don't have hypothyroidism, as the body can undergo changes that may require you to alter your diet or lifestyle in some way. Of the various nutrients whose deficiencies contribute to hypothyroidism, Vitamin A, D, iodine and selenium are probably at the highest risk of being dangerously low. It is advisable to consume a diet rich in these nutrients to ensure your hypothyroidism is contained. The top ten nutrients you should be monitoring if you suffer from thyroid problems are:

  • Protein
  • Magnesium
  • Vitamin D
  • Vitamin A
  • Selenium
  • Zinc
  • Iodine
  • Vitamin C
  • B-12
  • B2

Various other factors can increase the risk of developing hypothyroidism. These include:

  • Age: Women above the age of fifty are particularly at risk of developing hypothyroidism. 
  • Medical History: Patients with a history of various autoimmune diseases - or current conditions - can be more susceptible to hypothyroidism. These diseases may include multiple sclerosis, rheumatoid arthritis, and celiac disease
  • Family Relations: Having family members with thyroid problems may slightly increase the possibility of you developing them too.
  • Treatment with anti-thyroid drugs and radiation
  • Partial or complete thyroid surgery
  • Pregnancy: Being pregnant renders you prone to a number of medical risks, and thyroid issues are among such risks.
  • Other Rare Disorders: There are a number of rare disorders that may find a way to infiltrate the thyroid and impede its ability to function normally. These diseases cause another bodily unction to deposit a strange substance in the thyroid, rendering it incapable of doing its job. Some of these disorders include hemochromatosis, amyloidosis, and sarcoidosis.

If you think you may be demonstrating signs and symptoms of hypothyroidism, it is wise to voice your concerns to your doctor so he or she can attempt to make a diagnosis. Do not hesitate to see your general practitioner as soon as you feel something is wrong.