what are thyroid problems.docx

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What is the thyroid gland?

The thyroid gland is a butterfly-shaped endocrine gland that is normally located in the lower

front of the neck. The thyroids job is to make thyroid hormones, which are secreted into the

blood and then carried to every tissue in the body. Thyroid hormone helps the body useenergy, stay warm and keep the brain, heart, muscles, and other organs working as they

should.

What Are Thyroid Problems?

The thyroid is a butterfly-shaped gland located in the front of the neck just below the Adams

apple. The gland wraps around the windpipe (trachea) and has a shape that is similar to a

butterfly formed by two wings (lobes) and attached by a middle part (isthmus). The thyroid

gland works like a tiny factory that uses iodine (mostly from the diet in foods such as seafood

and salt) to produce thyroid hormones. These hormones help to regulate the body'smetabolism and effects processes, such as growth and other important functions of the body.

The two most important thyroid hormones are thyroxine (T4)

and triiodothyronine (T3), representing 99.9% and 0.1% of

thyroid hormones respectively. The hormone with the most

biological power is actually T3. Once released from the thyroid

gland into the blood, a large amount of T4 is converted to T3 -

the active hormone that affects the metabolism of cells

throughout our body.

Through the hormones it produces, the thyroid gland influencesalmost all of the metabolic processes in your body. Thyroid

disorders can range from a small, harmless goiter (enlarged

gland) that needs no treatment to life-threatening cancer. The

most common thyroid problems involve abnormal production

of thyroid hormones. Too much thyroid hormone results in a

condition known as hyperthyroidism. Insufficient hormone

production leads to hypothyroidism.

Although the effects can be unpleasant or uncomfortable, most thyroid problems can be

managed well if properly diagnosed and treated.

Thyroid Disease Symptoms:

The term goiter simply refers to the abnormal enlargement of the thyroid gland. It is

important to know that the presence of a goiter does not necessarily mean that the thyroid

gland is malfunctioning. A goiter can occur in a gland that is producing too much hormone

(hyperthyroidism), too little hormone (hypothyroidism), or the correct amount of hormone

(euthyroidism). A goiter indicates there is a condition present which is causing the thyroid to

grow abnormally.

The signs and symptoms of hypothyroidism vary widely and some of the complaintsexperienced by individuals with hypothyroidism include:
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Fatigue, Mental fogginess and forgetfulness, Feeling excessively cold, Constipation, Dry skin, Fluid retention, Non specific aches and stiffness in muscles and joints, Excessive or prolonged menstrual bleeding (menorrhagia), and Depression.

What Causes Thyroid Problems?

All types of hyperthyroidism are due to an overproduction of thyroid hormones, but the

condition can occur in several ways:

Graves' disease : The production of too much thyroid hormone Toxic adenomas: Nodules develop in the thyroid gland and begin to secrete thyroid

hormones, upsetting the body's chemical balance; some goiters may contain several of

these nodules.

Subacute thyroiditis: Inflammation of the thyroid that causes the gland to "leak"excess hormones, resulting in temporary hyperthyroidism that generally lasts a fewweeks but may persist for months

Pituitary gland malfunctions or cancerous growths in the thyroid gland:Although rare, hyperthyroidism can also develop from these causes.

What causes a goiter?

One of the most common causes of goiter formation worldwide is iodine deficiency. Whilethis was a very frequent cause of goiter in the United States many years ago, it is no longer

commonly observed. The primary activity of the thyroid gland is to concentrate iodine from

the blood to make thyroid hormone. The gland cannot make enough thyroid hormone if it

does not have enough iodine. Therefore, with iodine deficiency the individual will become

hypothyroid. Consequently, the pituitary gland in the brain senses the thyroid hormone level

is too low and sends a signal to the thyroid. This signal is called thyroid stimulating hormone

(TSH). As the name implies, this hormone stimulates the thyroid to produce thyroid hormone

and to grow in size. This abnormal growth in size produces what is termed a goiter. Thus,

iodine deficiency is one cause of goiter development. Wherever iodine deficiency is common,

goiter will be common. It remains a common cause of goiters in other parts of the world.
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Hashimotos thyroiditis is a more common cause of goiter formation in the US. This is an

autoimmune condition in which there is destruction of the thyroid gland by ones own

immune system. As the gland becomes more damaged, it is less able to make adequate

supplies of thyroid hormone. The pituitary gland senses a low thyroid hormone level and

secretes more TSH to stimulate the thyroid. This stimulation causes the thyroid to grow,

which may produce a goiter.

Another common cause of goiter is Graves disease. In this case, ones immune system

produces a protein, called thyroid stimulating immunoglobulin (TSI). As with TSH, TSI

stimulates the thyroid gland to enlarge producing a goiter. However, TSI also stimulates the

thyroid to make too much thyroid hormone (causes hyperthyroidism). Since the pituitary

senses too much thyroid hormone, it stops secreting TSH. In spite of this the thyroid gland

continues to grow and make thyroid hormone. Therefore, Graves disease produces a goiter

and hyperthyroidism.

Multinodular goiters are another common cause of goiters. Individuals with this disorder

have one or more nodules within the gland which cause thyroid enlargement. This is oftendetected as a nodular feeling gland on physical exam. Patients can present with a single large

nodule or with multiple smaller nodules in the gland when first detected. Thus, in early stages

of a multinodular goiter with many small nodules, the overall size of the thyroid may not be

enlarged yet. Unlike the other goiters discussed, the cause of this type of goiter is not well

understood.

In addition to the common causes of goiter, there are many other less common causes. Some

of these are due to genetic defects, others are related to injury or infections in the thyroid, and

some are due to tumors (both cancerous and benign tumors).

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 forheart 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 muchiodine, 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.
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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 comparedto younger people.

Autoimmune disease: individuals with a medical history of autoimmune disease, aswell 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 becomespregnant, or goes through the menopause.

Some medicines: antiretrovirals, immunosuppressants, amiodarone (heartmedication), and lithium increase a patient's risk of developing goiter.

Radiation: people whose neck or chest areas have been exposed to radiation have ahigher 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 andexpand.

Hypothyroidism: an under-active thyroid gland can also result in goiter. If the bodydoes 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 andgoiter risk. A person who smokes and has a low-iodine diet has a significantly higher

risk of developing goiter.
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Some infections: there are some parasites, bacteria and fungi which are known toincrease goiter risk of the patient become infected with them.

Some foods: some foods are known to suppress the function of the thyroid gland iftoo much of them are 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 developinggoiter.

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 ofhormones 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 hormones. Inversely, an overactive thyroid will show higher-than-normal bloodlevels 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 meanthat the underlying cause is related to this.

Ultrasound - a transducer is held over the patient's neck. The ultrasound deviceproduces 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
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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 smallamount 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 thedoctor 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.
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Over-active thyroid - patients with an overactive thyroid will most likely beprescribed 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 overactivethyroid 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 iscaused 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 problemsbreathing 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
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Nerve damage that affects the voice box and gives the patient a permanenthoarse voice.

Damage to the parathyroid glands, which regulate body calcium levels.

Thyroid hormone regulation - the chain of command

The thyroid itself is regulated by another gland located in the brain, called the pituitary. In

turn, the pituitary is regulated in part by the thyroid (via a "feedback" effect of thyroid

hormone on the pituitary gland) and by another gland called the hypothalamus.

The hypothalamus releases a hormone called thyrotropin releasing hormone (TRH), which

sends a signal to the pituitary to release thyroid stimulating hormone (TSH). In turn, TSH

sends a signal to the thyroid to release thyroid hormones. If over activity of any of these three

glands occurs, an excessive amount of

thyroid hormones can be produced, thereby

resulting in hyperthyroidism. Similarly, if

under activity of any of these glands occurs, a

deficiency of thyroid hormones can result,

causing hypothyroidism.

Hypothalamus - TRH

Pituitary- TSH

Thyroid - T4 and T3

The rate of thyroid hormone production is

controlled by the pituitary gland. If there is

an insufficient amount of thyroid hormone

circulating in the body to allow for normal

functioning, the release of TSH is increasedby the pituitary in an attempt to stimulate

more thyroid hormone production. In contrast, when there is an excessive amount of

circulating thyroid hormone, TSH levels fall as the pituitary attempts to decrease the

production of thyroid hormone.

There is another hormone that is produced by the thyroid called calcitonin. Calcitonin is

produced by specific cells in the thyroid gland, and unlike T3 and T4, it is not involved in this

regulation of metabolism. Calcitonin is a hormone that contributes to the regulation of

calcium and helps to lower calcium levels in the blood. Excess calcium in the blood is

referred to as hypercalcemia.
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Hypothyroidism, by contrast, stems from an underproduction of thyroid hormones. Since

your body's energy production requires certain amounts of thyroid hormones, a drop in

hormone production leads to lower energy levels. Causes of hypothyroidism include:

Hashimoto's thyroiditis: In this autoimmune disorder, the body attacks thyroidtissue. The tissue eventually dies and stops producing hormones.

Removal of the thyroid gland: The thyroid may have been surgically removed orchemically destroyed.

Exposure to excessive amounts of iodide: Cold and sinus medicines, the heartmedicine amiodarone, or certain contrast dyes given before some X-rays may expose

you to too much iodine. You may be at greater risk for developing hypothyroidism if

you have had thyroid problems in the past.

Lithium: This drug has also been implicated as a cause of hypothyroidism.Untreated for long periods of time, hypothyroidism can bring on a myxedema coma, a rare

but potentially fatal condition that requires immediate hormone injections.

Hyperthyroidism is suggested by a number of signs and symptoms. People with mild

hyperthyroidism or those older than 70 years of age usually experience no symptoms. In

general, the symptoms become more obvious as the condition worsens. Common symptoms

of hyperthyroidism include:

excessive sweating, heat intolerance, increased bowel movements, tremor (usually a fine shake), nervousness; agitation, rapid heart rate, weight loss, fatigue, decreased concentration, and Irregular and scant menstrual flow.

Hypothyroidism poses a special danger to newborns and infants. A lack of thyroid

hormones in the system at an early age can lead to the development of cretinism (mental

retardation) and dwarfism (stunted growth). Most infants now have their thyroid levels

checked routinely soon after birth. If they are hypothyroid, treatment begins immediately. In

infants, as in adults, hypothyroidism can be due to these causes:

A pituitary disorder A defective thyroid Lack of the gland entirely
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Conclusion:Research on the treatment of thyroid disease is proceeding in promising directions.

Autoimmune thyroid disease is being intensively studied, and synthetic antibodies have been

produced that neutralize Graves' antibodies in mice. Other studies are uncovering the role of

TH in the brain, and finding new genetic causes of thyroid hormone metabolism disorders.

TH function is being studied in various vertebrates, and environmental chemicals areundergoing examination as possible TH disruptors. Such research provides hope that

autoimmune thyroid disease can one day be attacked at its source

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