What Is Goiter (goitre)? What Causes Goiter?

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Main Category: Endocrinology
Also Included In: Ear, Nose and Throat
Article Date: 15 Oct 2009 - 11:00 PST

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Goiter (UK: goitre) is the enlargement of the thyroid gland and is not cancerous. A person with goiter can have normal levels of thyroid hormone (euthyroidism), excessive levels (hyperthyroidism) or levels that are too low (hypothyroidism).

The thyroid is a gland, shaped like a butterfly, located at the base of the neck, just below the Adam's apple. If the thyroid gland grows larger than normal the patient has a condition known as goiter. Goiters are generally painless; however, if the gland gets very large the patient may have problems swallowing properly, and may also develop a cough.

Goiter refers both to the enlarged thyroid gland, and the condition of having an enlarged thyroid gland.

According to Medilexicon's medical dictionary, goiter is "A chronic enlargement of the thyroid gland, not due to a neoplasm, occurring endemically in certain localities, especially regions where glaciation occurred and the soil is low in iodine, and sporadically elsewhere."

Historically, goiter was commonly caused by a lack of iodine in a person's diet. However, as most countries add iodine to salt, it is more usually caused by an imbalance in thyroid hormone production, nodules that develop in the gland, or pregnancy. A significant number of people in some parts of the world still do develop goiter due to diet factors.

According to the National Health Service, UK, approximately 8.5% of British adults have goiter. However, in most cases the swelling is not enough to be noticeable or a problem. Goiters are more common in females than males. People of all ages can develop goiter. In some cases it may be present at birth.

What are the signs and symptoms of goiter?

A symptom is something the patient feels or reports, while a sign is something other people, including the doctor detects. For example, a headache may be a symptom while a rash may be a sign.

Some patients may have goiter and not know it because they have no symptoms.

The main symptom for a person with goiter is swelling of the thyroid gland. This may eventually become a noticeable lump in the throat. The patient may be more aware of it - a visible swelling at the base of the neck - when looking in the mirror and shaving or putting on makeup.

There are two types of goiter:

• Diffuse small goiter - the whole thyroid gland swells. When touched it feels smooth.


• Nodular goiter - certain parts of the thyroid gland - nodules - swell. The gland may feel lumpy when touched.

The following symptoms may also exist when a person has goiter:

• Hoarseness (voice)
• Coughing more frequently than usual
• A feeling of tightness in the throat
• Swallowing difficulties (less common)
• Breathing difficulties (less common)

What are the causes and risk factors for goiter?

A risk factor is something which increases the chances of developing a condition or disease. For example, a risk factor for heart disease is smoking - if you smoke regularly your risk of developing heart disease is increased.

The possible causes and risk factors for goiter include:

• A diet poor in iodine - may affect people who live in areas where there is not much iodine, or those who don't have access to iodine supplements. In many countries iodine deficiency used to be the main cause of goiter. It still is in some countries, and areas within some countries.
  
  Iodine, a trace element, exists in the soil and sea. Fish, seafood, many vegetables and dairy products contain iodine. Our thyroid gland needs iodine in order to make thyroid hormones. If there is not enough iodine in a person's body their thyroid gland will get bigger so that it can produce more hormones.
  
  In the UK, USA and many other countries iodine deficiency used to be common until iodine was added to salt in the early 1900s. As more people these days are opting for low salt and low dairy diets, the number of cases of iodine deficiency has started to rise in the UK and USA.


• Gender - women are more likely to develop goiter compared to men.


• Age - people over the age of 50 are significantly more likely to have goiter compared to younger people.


• Autoimmune disease - individuals with a medical history of autoimmune disease, as well as those with a close relative who have/had autoimmune disease have a higher risk of developing goiter.


• Pregnancy and menopause - goiter is more likely to happen after a woman becomes pregnant, or goes through the menopause.


• Some medicines - antiretrovirals, immunosuppressants, amiodarone (heart medication), and lithium increase a patient's risk of developing goiter.


• Radiation - people whose neck or chest areas have been exposed to radiation have a higher risk. This could be due to radiation treatment (radiotherapy), or having worked in a nuclear facility, being involved in a nuclear test or accident.


• Hyperthyroidism - if the thyroid is over-active it can become over-stimulated and expand.


• Hypothyroidism - an under-active thyroid gland can also result in goiter. If the body does not have enough of the hormones produced by the thyroid gland it will stimulate the gland to produce more, which can lead to swelling of the gland.


• Smoking - some studies suggest that there is a link between regular smoking and goiter risk. A person who smokes and has a low-iodine diet has a significantly higher risk of developing goiter.


• Some infections - there are some parasites, bacteria and fungi which are known to increase goiter risk of the patient becomes infected with them.


• Some foods - some foods are known to suppress the function of the thyroid gland if too much of them is consumed - these are known as goitrogenic foods. They include peanuts, soybeans, tofu and spinach.


• Too much iodine - consuming too much iodine can raise the risk of developing goiter.


• Thyroid cancer - people who have thyroid cancer have a higher risk of developing goiter.

Diagnosis of goiter

A GP (general practitioner, primary care physician) may detect a swollen thyroid gland by feeling the patient's neck and asking him/her to swallow during a routine physical exam. Sometimes the nodules may also be detected simply by touch. A physical examination of the neck may also allow the doctor to assess the size of the thyroid gland and the extent of the swelling.

The doctor may order some more tests to find out what the underlying cause might be. Examples of possible tests include:

• A hormone test - this will be done with a blood test which can show levels of hormones produced by the thyroid as well as pituitary glands. Low blood levels of thyroid hormone will mean the patient's thyroid is underactive. TSH (thyroid-stimulating hormone) levels will be high if thyroid hormone levels are low. TSH is produced by the pituitary gland in an attempt to stimulate the thyroid gland to produce more hormone. Inversely, an overactive thyroid will show higher-than-normal blood levels of thyroid hormone and lower-than-normal blood levels of TSH.


• An antibody test - if the blood test confirms the presence of antibodies it could mean that the underlying cause is related to this.


• Ultrasound - a transducer is held over the patient's neck. The ultrasound device produces sound waves which bounce through the neck and return, like an echo. The variations in the echo timings are processed and an image of the inside of the neck can be seen by the doctor on a screen. This procedure allows the doctor to see how big the thyroid gland is and whether there are any nodules.


• A thyroid scan (radioactive iodine scan) - the patient is injected with a small amount of radioactive iodine, usually into a vein on the inside of the elbow. He/she lies on a table with the head stretched backward while a camera produces an image of the thyroid on a monitor.
  
  The radioactive iodine accumulates in the thyroid gland and shows up in the scan.
  
  This scan helps the doctor determine the size, structure and function of the thyroid gland.
  
  The amount of radiation is not hazardous to the patient's health. It may not be suitable for pregnant women.

What are the treatment options for goiter?

The type of treatment may depend on various factors, including the size of the thyroid gland, symptoms and their severity, and any underlying conditions. If the patient's goiter is small, the thyroid gland is working properly and there are no underlying conditions the doctor will probably recommend long-term monitoring, but no treatment.

• Underactive thyroid - if the patient is found to have an underactive thyroid the doctor may prescribe the use of synthetic hormone, levothyroxine (Levothroid, Synthroid), to make up for the shortfall. The patient will swallow a pill once a day. Possible side effects of this hormone therapy may include:
  
  
  • Muscle cramps
  • Irregular heart beat
  • Pain in the chest
  
  In most cases side effects go away after a few days.
  
  These side effects are also possible, but they are rare:
  
  
  • Insomnia
  • Diarrhea
  • Hot flashes
  • Weight loss
  • Excessive sweating
  • Accelerated heart beat
  • Headaches
  
  Patients who experience any of these unusual side effects should tell their doctor immediately, because the dosage may need adjusting.


• Over-active thyroid - patients with an overactive thyroid will most likely be prescribed thionamides, which help lower the amount of thyroids hormones being produced by the thyroid gland.
  
  This medication is generally taken by mouth (orally). Patients may not notice any effect for several weeks. Side effects may include:
  
  
  • Skin rash (usually mild)
  • Itchy skin
  • Joint pain
  • Nausea
  • Agranulocytosis - a serious drop in the number of granulocytes. Granulocytes are a kind of white blood cell filled with microscopic granules - small sacs containing enzymes that digest microorganisms. This side effect is extremely rare. If it does occur it will do so during the first three months of treatment.
  
  Any patient who develops a fever, sore throat, mouth ulcers, or any signs of infection, and is taking thionamides should seek immediate medical attention.
  
  Treatment with thionamides usually lasts from two to four months.


• Radioactive iodine - this is a possible treatment option for patients with an overactive thyroid gland. The iodine is taken by mouth. The radioactive iodine destroys thyroid cells when it reaches the thyroid gland, resulting in a smaller goiter. The patient may end up with an under-active thyroid gland, and subsequently need hormone therapy.


• Iodine supplements - the patient will be prescribed iodine supplements if the goiter is caused by an iodine deficiency. Iodine supplements are available OTC (over-the-counter, no prescription required). It is important to follow the dosage prescribed by your doctor. We do not all have the same iodine requirements.


• Surgery - this is an option if the goiter is so large that the patient has problems breathing or swallowing and other treatments have not worked.
  
  In most cases half the thyroid gland will be surgically removed. The surgeon will remove enough of the gland to relieve symptoms, while at the same time try not to underme the gland's ability to manufacture hormones. Some patients, however, will need hormone therapy after surgery. Possible complications from surgery include:
  
  
  • Infection
  • Nerve damage that affects the voice box and gives the patient a permanent hoarse voice.
  • Damage to the parathyroid glands, which regulate body calcium levels.

What are the possible complications of goiter?

While small goiters do not usually cause any problems, large ones can make it hard for the patient to breathe and swallow properly, as well as causing a cough and hoarseness.

If the goiter is caused by an underlying problem, such as hypothyroidism or hyperthyroidism, the possible complications will be related to those conditions.

Written by Christian Nordqvist


Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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