Hypothyroidism

A small part of your neck helps you.

It makes things your body needs. Sometimes it does not make enough. This can make you feel very tired. It can also make you feel cold.

Not having enough can cause weight gain. It can also make your skin feel dry. Some people get a swelling in their neck. This happens when the small part grows too big.

One big cause is not having enough iodine. Iodine is something found in salt. Adding it to salt helps many people. This keeps the neck part working well.

This can happen to women more than men. It can also happen to older people. Even dogs and cats can get it. It is good to talk to a doctor.

Your body has a small part in your neck called the thyroid gland.

This gland makes hormones. These are special chemicals that help your body work. Hypothyroidism happens when the gland does not make enough of these hormones.

Many things can cause this. In many parts of the world, it is caused by not having enough iodine in your food. Iodine is a mineral found in salt. In other places, an autoimmune disease called Hashimoto's thyroiditis is a common cause. This is when your body's own immune system attacks the thyroid gland.

When you do not have enough hormone, you might feel many ways. You may feel very tired or feel cold easily. Other signs include weight gain, dry skin, or a slow heart rate.

Sometimes the neck part grows large. This is called a goiter.

Doctors use blood tests to check your levels. They look for TSH and T4. TSH is a hormone that tells the thyroid to work. T4 is the main hormone the thyroid makes. If levels are low, doctors may give you medicine to replace the hormone.

This medicine is safe for women who are pregnant.

Hypothyroidism is a condition involving the thyroid gland. This gland sits in the front part of your neck.

It is an endocrine gland, which means it makes hormones. These hormones are special chemicals that help your body work. Hypothyroidism happens when the gland does not produce enough of these hormones. This can cause many different symptoms. You might feel extreme fatigue or have muscle aches. Some people feel cold easily or gain weight.

It can also cause a slow heart rate or constipation.

To understand how it works, we must look at a special chain of signals. This is called the hypothalamic-pituitary-thyroid axis. First, a part of the brain called the hypothalamus releases a hormone called TRH. This hormone tells the pituitary gland to make another hormone called TSH. The TSH then tells the thyroid gland to make thyroxine, or T4. The thyroid uses iodine from your blood to make these hormones.

When thyroxine levels are high enough, they tell the brain to slow down. This is a negative feedback process that keeps things balanced. If the gland fails, the balance is lost.

Scientists and doctors have learned a lot about why this happens. In many parts of the world, the main cause is not eating enough iodine. Iodine is a mineral found in certain foods and salt. In places where there is enough iodine, a different cause is most common. This is an autoimmune disease called Hashimoto's thyroiditis. In this condition, the body's own immune system attacks the thyroid gland. This can sometimes cause the gland to swell into a lump called a goiter.

There are many important facts and numbers to know about this condition. In the United States, about 0.3% to 0.4% of people have overt hypothyroidism. A milder form called subclinical hypothyroidism affects about 4.3% to 8.5% of people there. This condition is more common in women than in men. It is also more common in people over the age of 60. Even animals like dogs, cats, and horses can get it.

For babies, untreated cases can lead to delays in growth and learning.

Doctors can find hypothyroidism by using simple blood tests. They measure the levels of TSH and T4 in the blood. If the levels are too low, they can give medicine. This medicine is called levothyroxine. It replaces the hormone that the body is missing. This treatment is safe for women who are pregnant.

Managing these levels helps the body return to its normal state. It is a way to help the body's systems work together again.

Hypothyroidism is a chronic endocrine disease. It occurs when the thyroid gland fails to produce enough thyroid hormones. The thyroid is a gland located in the front of the neck. It is the only source of thyroid hormone in the human body. These hormones are vital for the normal functioning of many different tissues. Without enough hormone, the body's many systems can slow down. This condition can affect humans and animals like dogs, cats, and horses.

To understand how this happens, we must look at the hypothalamic-pituitary-thyroid axis. This is a chain of signals that maintains hormonal balance. First, the hypothalamus releases thyrotropin-releasing hormone, or TRH. This hormone stimulates the anterior pituitary gland to produce thyroid-stimulating hormone, or TSH. The TSH then signals the thyroid gland to produce thyroxine, also known as T4. The thyroid uses iodine and the amino acid tyrosine to create these hormones.

This system uses a process called negative feedback to stay balanced. When thyroxine levels are sufficient, they signal the hypothalamus and pituitary to decrease TRH and TSH production. In the body, T4 is often converted into triiodothyronine, or T3, by an enzyme called iodothyronine deiodinase. T3 then binds to receptors in cell nuclei to turn on specific genes. This process regulates cell growth and many other vital functions. If the thyroid cannot produce enough hormone, this delicate balance is lost.

Doctors categorize hypothyroidism into different types based on where the failure occurs. Primary hypothyroidism is the most common type. It happens when the thyroid gland itself cannot function properly. Secondary and tertiary hypothyroidism are known as central hypothyroidism. Secondary hypothyroidism occurs when the pituitary gland fails to release enough TSH. Tertiary hypothyroidism happens when the hypothalamus fails to release enough TRH. Primary hypothyroidism is about a thousand times more common than central hypothyroidism.

There are several specific causes for these conditions. Globally, the most common cause of primary hypothyroidism is iodine deficiency. In countries with enough dietary iodine, Hashimoto's thyroiditis is the leading cause. Hashimoto's is an autoimmune disease. In this condition, the body's immune system attacks the thyroid gland using T lymphocytes and autoantibodies. Other causes include previous thyroid surgery, or treatments involving radioactive iodine. Some medications, such as lithium, can also cause the condition.

Symptoms of hypothyroidism can be very diverse. Some people experience only mild signs, while others have severe issues. Common symptoms include extreme fatigue, weight gain, and constipation. People may also feel cold easily or experience a slow heart rate. Physical signs can include dry skin, hair loss, and a swelling in the neck called a goiter. In rare, extreme cases, a person may develop myxedema coma. This is a life-threatening state characterized by low body temperature and confusion.

Hypothyroidism is particularly significant during pregnancy and childhood. Untreated cases in pregnant women can lead to miscarriage or infant death. It can also cause delays in a baby's growth and intellectual development. For newborns, symptoms might include drowsiness, poor weight gain, or a hoarse cry.

In severe cases, children may face intellectual impairments of 6 to 15 IQ points. In the United States, overt hypothyroidism affects about 0.3% to 0.4% of people. Subclinical hypothyroidism, a milder form, affects between 4.3% and 8.5% of the population.

Medical professionals diagnose the condition using blood tests. They measure levels of TSH and thyroxine (T4) to confirm the diagnosis. The standard treatment is thyroid hormone replacement therapy using levothyroxine. This medication replaces the missing hormone to restore balance. Doctors adjust the dosage based on a patient's symptoms and TSH levels. This treatment is considered safe for use during pregnancy. Maintaining these levels helps the body's systems function normally again.