Why hypothyroidism occurs

Hypothyroidism has many symptoms that can vary from person to person. Some common symptoms of hypothyroidism include. Because hypothyroidism develops slowly, you may not notice symptoms of the disease for months or even years. Many of these symptoms, especially fatigue and weight gain, are common and do not necessarily mean you have a thyroid problem.

Less often, hypothyroidism is caused by too much or too little iodine in the diet or by disorders of the pituitary gland or hypothalamus. With this disease, your immune system attacks the thyroid. Thyroiditis, an inflammation of your thyroid, causes stored thyroid hormone to leak out of your thyroid gland. The thyrotoxicosis may last for many months. After that, your thyroid may become underactive and, over time, the condition may become permanent, requiring thyroid hormone replacement.

Some babies are born with a thyroid that is not fully developed or does not work properly. Early treatment can prevent these problems. When surgeons remove part of the thyroid, the remaining part may produce normal amounts of thyroid hormone. But some people who have this surgery may develop hypothyroidism. Removing the entire thyroid always results in hypothyroidism. Radioactive iodine, a common treatment for hyperthyroidism, gradually destroys thyroid cells.

If you receive radioactive iodine treatment, you probably will eventually develop hypothyroidism. Doctors also treat people who have head or neck cancers with external radiation therapy , which can also damage the thyroid if it is included in the treatment. Download it on Google Play or the App Store. By subscribing you agree to the Terms of Use and Privacy Policy. References Statistics for Thyroid Diseases. Florida Hospital. Journal of the American Medical Association.

April Hypothyroidism Underactive Thyroid. Mayo Clinic. December 6, American Thyroid Association. Thyroid Disease. Hypothyroidism: Symptoms, Diagnosis, and Treatment.

PubMed Health. August 10, Thyroid Function Tests. American Thyroid Foundation. Health Topics. Health Tools. Reviewed: April 25, Medically Reviewed. Doctors usually carry out a physical examination, take a medical history, and sent to a laboratory for analysis. If the TSH reading is above normal, the patient may have hypothyroidism. If TSH levels are below normal, the patient may have hyperthyroidism or hypothyroidism.

The T3, T4, and thyroid autoantibody tests are additional blood tests used to confirm the diagnosis or determine its cause. The doctor may run a complete thyroid panel, testing levels of T3 and T4, TSH, and thyroid autoantibodies in order to fully establish the health and activity of the thyroid gland. Compare home thyroid hormone and TSH tests. People have a greater risk of developing a thyroid disorder if they have conditions such as Turner syndrome or autoimmune diseases like lupus or rheumatoid arthritis.

The risk of hypothyroidism is higher in people with a family history of thyroid disease and those aged over 60 years. In one study, 85 percent of women who are pregnant and taking thyroid hormone replacement needed an additional intake of 47 percent on average, during pregnancy. This condition affects between 3 and 5 out of every 1, women during pregnancy.

Uncontrolled hypothyroidism increases the risk of miscarriage, preterm delivery, and a rise in blood pressure during late pregnancy, or preeclampsia. Women who have been pregnant within the last 6 months have a higher risk of thyroiditis and hypothyroidism. Myxedema coma is a complication of hypothyroidism. This condition is also known as myxedema crisis.

Learn more about the symptoms and treatment of…. Certain foods and supplements may improve or worsen symptoms of hypothyroidism, or an underactive thyroid. Here, we describe changes to the diet that…. What is hypothyroidism? Medically reviewed by Natalie Butler, R. Share on Pinterest Hypothyroidism refers to the underproduction of hormones in the thyroid gland. It has a wide range of symptoms.

Share on Pinterest Hypothyroidism can occur after part of the thyroid is removed during surgery. Natural remedies. Risk factors. Share on Pinterest Pregnancy can be a cause of hypothyroidism. Endocrinology Hypothyroid. Latest news Could 'cupping' technique boost vaccine delivery? Medicines such as amiodarone, lithium, interferon alpha, and interleukin-2 can prevent the thyroid gland from being able to make hormone normally. These drugs are most likely to trigger hypothyroidism in patients who have a genetic tendency to autoimmune thyroid disease.

Too much or too little iodine. The thyroid gland must have iodine to make thyroid hormone. Iodine comes into the body in food and travels through the blood to the thyroid. Keeping thyroid hormone production in balance requires the right amount of iodine. Taking in too much iodine can cause or worsen hypothyroidism. Damage to the pituitary gland.

When the pituitary is damaged by a tumor, radiation, or surgery, it may no longer be able to give the thyroid instructions, and the thyroid may stop making enough hormone. Rare disorders that infiltrate the thyroid. In a few people, diseases deposit abnormal substances in the thyroid and impair its ability to function. For example, amyloidosis can deposit amyloid protein, sarcoidosis can deposit granulomas, and hemochromatosis can deposit iron.

The correct diagnosis of hypothyroidism depends on the following: Symptoms. There are no symptoms that people with hypothyroidism always have and many symptoms of hypothyroidism can occur in people with other diseases. Medical and family history. Physical exam. The doctor will check your thyroid gland and look for changes such as dry skin, swelling, slower reflexes, and a slower heart rate.

Blood tests. There are two blood tests that are used in the diagnosis of hypothyroidism. TSH thyroid-stimulating hormone test.