What is thyroid disease? What are thyroid diseases? How is it understood? What are the symptoms? Is it a serious situation? Is there any interest? How is it treated? You can find the answers to all these questions and much more below.
What is thyroid disease?
The thyroid is a small, butterfly-shaped gland in the front of your neck that surrounds your windpipe (trachea), and thyroid disease is related to problems with this tiny organelle. In fact, there are multiple thyroid diseases .
The two halves of the thyroid gland are connected in the middle by a thin layer of tissue known as the isthmus . The thyroid gland uses iodine (which is mostly absorbed from food) to produce hormones that control how your body uses energy. Almost every organ in the body is affected by the function of the thyroid gland.
The pituitary gland and hypothalamus, an area at the base of the brain, control the rate at which the thyroid produces and releases these hormones. The main function of the thyroid gland is to release the hormones T3 and T4. Both of these hormones travel through the bloodstream and help regulate your metabolism.
The amount of T4 produced by the thyroid gland is determined by the pituitary gland by a hormone called TSH or thyroid stimulating hormone. Depending on T4 levels in the body, the pituitary gland produces more or less TSH to keep the thyroid producing the appropriate amount of T4.
Thyroid diseases usually occur when this cycle is disrupted. You will find more detailed information below.
What are thyroid diseases?
Thyroid diseases usually occur when the thyroid releases too much T4 hormone or doesn’t release enough and isn’t working properly. There are three main thyroid diseases:
- Hypothyroidism (underactive thyroid)
- Hyperthyroidism (overactive thyroid)
- thyroid cancer
1- Hypothyroidism (underactive thyroid)
Hypothyroidism in thyroid diseases occurs when the thyroid gland does not produce enough T4 hormone. This condition can also be called under -functioning of the thyroid gland . An underactive thyroid can occur because the pituitary gland, hypothalamus, or the thyroid itself is not working properly.
About five percent of the population has an underactive thyroid, or underactive thyroid gland; More women than men are affected by this condition. Symptoms of an underactive thyroid include:
- high cholesterol
- hair loss
- Loss of memory
- Extremely dry skin
- To feel cold
2- Hyperthyroidism (overactive thyroid)
Hyperthyroidism in thyroid diseases occurs when the thyroid gland produces more thyroid hormone than the body needs. This situation can also be called the rapid functioning of the thyroid gland . An overactive thyroid can occur because the hypothalamus, pituitary gland, or the thyroid itself isn’t working properly. An overactive thyroid is not very common.
For example, it affects just over one percent of the U.S. population. Just like the underactive thyroid gland, more women than men are affected by this condition.
Symptoms of hyperthyroidism (fast work of the thyroid gland), a relatively common thyroid disease, include:
- weight loss
- fast heart rate
- heat intolerance
- Irregular menstrual periods
- skin changes
- sleep changes
- Frequent big toilet needs
- Goiter (a condition that looks like a large mass protruding from the neck of the thyroid gland and is caused by excess hormone production in the gland)
Elderly patients may experience arrhythmias (irregular heart rhythms), heart failure, and mental confusion (delirium). If left untreated, patients can develop high blood pressure, heart failure, and a condition where fever can lead to a critical condition that requires immediate medical care.
3- Thyroid cancer
Thyroid cancer, the most dangerous of the thyroid diseases , occurs when cells in the thyroid change and multiply, and the cancerous cells form nodules or growths. If left untreated, these cancerous nodules can spread to the lymph nodes, surrounding tissues, and bloodstream.
Thyroid cancer is rare. However, rates have been increasing over the past 30 years. Experts believe this increase is mostly due to better detection using ultrasound technology. Most thyroid cancers are treatable. There are four types of thyroid cancer.
Papillary thyroid cancer
70 percent of patients diagnosed with thyroid cancer on suspicion of having thyroid disease have papillary thyroid cancer. This cancer begins in the follicular cells where thyroid hormone is stored. Its progression is slow, but in 20 percent of patients it has spread to the lymph nodes of the neck because it is noticed late.
Follicular thyroid cancer
Like papillary thyroid cancer, follicular thyroid cancer begins in the follicular cells. However, it is much more aggressive than papillary cancer and often spreads to the bloodstream, lungs, or bones. Most patients with follicular thyroid cancer are over the age of 40.
A rare type of follicular thyroid cancer among thyroid diseases is also called Hurthle cell cancer . Hurthle cell cancers are more likely to have metastasized (spread) at diagnosis than other types of differentiated thyroid cancer.
Medullary thyroid cancer
Medullary thyroid cancer is rare. Only four percent of patients diagnosed with thyroid cancer have this type of cancer. It develops in the C cells of the thyroid, which make a hormone called calcitonin . Calcitonin helps the body maintain proper calcium levels.
Among the thyroid diseases, medullary thyroid cancer may be associated with other types of cancer and may also be genetic. This cancer has a lower cure rate than papillary or follicular thyroid cancers.
anaplastic thyroid cancer
Anaplastic thyroid cancer is the rarest form of thyroid cancer. It affects only about one percent of patients diagnosed with thyroid cancer. It is the most aggressive and difficult thyroid cancer to treat. Anaplastic cancer is often called “undifferentiated” because the cells do not look like or act like typical thyroid cells.
It can occur in follicular, papillary thyroid cancer or in a goiter. Most patients diagnosed with anaplastic thyroid cancer are over the age of 60. Most patients with anaplastic thyroid cancer have metastases (secondary tumors) at diagnosis.
What are the causes and symptoms of thyroid diseases?
Thyroid diseases have many causes. Conditions that determine how thyroid functions are affected include:
Thyroiditis (inflammatory thyroid disease)
The thyroid gland may become inflamed for unknown reasons, and thyroiditis, one of the thyroid diseases, may occur. This inflammation causes extra thyroid hormone to leak into the bloodstream and causes too much thyroid hormone to circulate throughout the body, or hyperthyroidism (overactive thyroid gland). This period of hyperthyroidism typically lasts no more than three months. Eventually, the thyroid temporarily or permanently releases very little T4 hormone.
A viral or bacterial infection may be the cause of some thyroiditis. The condition can also occur after birth. Most of the time, the inflammation is painless. However, for patients with a condition called subacute granulomatous thyroiditis , pain around the thyroid can last for several weeks.
Hashimoto’s disease or chronic lymphocytic thyroiditis (inflammatory thyroid disease)
Hashimoto’s disease , which is also associated with inflammation among thyroid diseases, occurs when the patient’s own immune system identifies the thyroid as foreign and produces antibodies that attack it. The thyroid becomes chronically inflamed from these attacks and the body stops producing enough thyroid hormone to function properly.
Scientists believe possible causes of Hashimoto’s disease include a virus or bacteria that triggers an overactive immune response and a genetic predisposition to the disorder. People suffering from other autoimmune disorders such as rheumatoid arthritis , lupus disease , and type 1 diabetes , and people exposed to higher levels of environmental radiation, have a higher risk of developing the disease.
Pituitary or hypothalamic disease
Because the thyroid is regulated by the pituitary gland and hypothalamus, injury or dysfunction in these areas can cause the thyroid to malfunction, resulting in a condition known as secondary hypothyroidism or tertiary hypothyroidism .
Because the thyroid gland works quickly, patients receiving radioactive iodine typically develop hypothyroidism (underactive thyroid gland) after treatment. Patients receiving this treatment for cancer treatment or for other reasons may experience thyroid dysfunction .
The most common cause of overactive thyroid gland is Graves’ disease . It occurs when the immune system produces antibodies that cause the thyroid to grow and produce more T4 thyroid hormone than the body needs. In healthy people, the amount of T4 is regulated by TSH (thyroid stimulating hormone). Patients with Graves’ disease release antibodies that mimic TSH and persuade the thyroid to produce more T4 than necessary, leading to an overactive thyroid.
Antibodies that attack the thyroid usually attack the tissue behind the eyes, a condition known as Graves’ ophthalmopathy or thyroid eye disease . This condition can cause mild symptoms such as red and irritated eyes or sensitivity to light.
It can also cause one or both eyes to protrude from the eye sockets as a result of inflammation and swelling in the muscles and tissues in the eye socket. People with Graves’ disease may develop a thickening and redness of the skin on the front of their lower legs, a condition called Graves’ dermopathy .
Hyperfunctional thyroid nodules
This condition is also called toxic adenoma , toxic multinodular goiter , or plummer’s disease . Noncancerous nodules called adenomas occur when part of the thyroid gland begins to swell and separate from the rest of the gland.
These adenomas may begin to produce thyroid hormones independently of the rest of the thyroid gland, a condition called a functioning nodule. When these nodules do not respond to the normal feedback mechanisms used to keep thyroid hormone levels in check, it is known as a toxic adenoma or Plummer’s disease.
How are thyroid diseases diagnosed?
Symptoms often prompt patients to see a doctor, such as fatigue, inability to become pregnant, changes in skin and hair, a lump in the neck, hoarseness or pain in the thyroid area.
Based on these symptoms, he or she will likely do a physical exam to determine if the thyroid is enlarged and order blood tests to measure thyroid hormone levels.
If blood tests for suspected thyroid conditions reveal abnormal thyroid activity or signs of thyroid cancer, further testing will be needed, such as:
A small amount of radioactive iodine (radioiodine) is swallowed during this test for the diagnosis of thyroid diseases. Over a period of time, iodine accumulates in the thyroid. After a few hours, you will be placed in front of a special camera called a gamma camera to measure the amount of iodine absorbed by your thyroid . This device emits no radiation, but swallowed or injected radioiodine may contain very small amounts of radiation.
Ultrasound guided fine needle aspiration biopsy
During a fine-needle aspiration biopsy of the thyroid, a thin, hollow needle is inserted through the skin and into the thyroid gland or suspicious nodule. To determine if cancer is present, a small sample of tissue is taken for examination under a microscope and tested for thyroid diseases.
If it is determined that you have thyroid cancer, your doctor will order one or more imaging studies to determine the size and location of the thyroid cancer and whether it has spread.
How are thyroid diseases treated?
Treatment for thyroid diseases will vary depending on which disease you are affected by.
Hypothyroidism treatment (What should be done for the thyroid gland to work fast?)
Synthetic (man-made) thyroid hormone known as levothyroxine is given as a treatment for underactive thyroid gland. Levothyroxine restores your body’s hormone levels and provides symptom relief.
Your blood will be tested periodically to make sure the drug is controlling your hypothyroidism. It may take several months to determine the correct dose needed to control your symptoms. Patients with an underactive thyroid usually need to take thyroid hormone for the rest of their lives.
Hyperthyroidism treatment (What should be done for the thyroid gland to work less?)
Treatment for thyroid gland hyperactivity depends on how severe the symptoms are and what the underlying cause is. You and your doctor will decide together which of the following options is best for you:
For hyperthyroidism among the thyroid diseases , drugs such as methimazole prevent the thyroid from producing too much thyroid hormone. It is often used for patients suffering from Graves’ disease or before thyroid surgery. Relief of symptoms typically occurs 6 to 12 weeks after starting medication, but treatment usually continues for at least a year.
While 20 to 30 percent of patients get permanent relief, others may find symptoms return. Anti-thyroid drugs can affect your liver and increase your risk of infection. A small number of people are allergic to these drugs.
Radioactive iodine (I-131), an isotope of iodine that emits radiation, is commonly used to treat hyperthyroidism. When a small dose of I-131 is swallowed, it enters the bloodstream and is absorbed by the thyroid gland. Over a period of three to six months, patients often see their symptoms subside.
Radioactive iodine typically causes the thyroid to become underactive, and many patients need daily synthetic thyroid hormone to restore adequate hormone levels in the body. Radioactive iodine has been used for decades and is safe.
This is a class of drugs used to treat high blood pressure. Beta blockers do not directly treat hyperthyroidism, a thyroid disease, but they can help reduce a rapid heart rate and prevent heart palpitations.
Beta blockers are often given with anti-thyroid medication and radioactive iodine to help patients feel better until the thyroid is functioning more normally. Beta blockers are generally well tolerated, but patients may experience upset stomach, diarrhea, dizziness or headache.
For thyroid patients with hyperthyroidism who cannot take anti-thyroid medication or radioactive iodine, surgical removal of the thyroid, called a thyroidectomy, is an option. For this procedure, the surgeon makes an incision at the base of the neck and removes most of the thyroid gland.
In minimally invasive video-assisted thyroidectomy, a smaller incision is made and the surgeon is assisted by a video camera. Most surgeries take around 2 hours. Patients are discharged either the same day or the next day after a short observation period.
While complications from thyroid surgery are rare, there are always risks associated with the surgery. An experienced surgeon can help avoid complications such as damage to the parathyroid glands (causing low calcium levels) or vocal cords (causing hoarseness).
After the thyroid gland is removed, patients need lifelong replacement of thyroid hormones with synthetic hormones. If the parathyroid glands are also removed, patients will also need calcium supplements.
Thyroid cancer treatment
Most thyroid cancers within thyroid diseases are treated with surgery to remove the thyroid gland. Radioactive iodine therapy is often used after surgery to destroy any remaining thyroid tissue. This includes both remaining healthy tissue and remaining cancer cells.
Depending on the stage of the cancer, lymph nodes in the neck may also be removed for testing. In some cases where the cancer is very small, only part of the gland may be removed. Partial removal of the gland is called a thyroid lobectomy .
After surgery, most patients will need to take synthetic thyroid hormone daily for the rest of their lives. You and your doctor can determine the best surgical option for you, based on the type of cancer you have and whether it has spread.