THYROID DISORDERS

What are thyroid disorders?

Thyroid disorders are conditions that affect the thyroid gland and cause dysfunction of the thyroid gland. The three main problems that can lead to a thyroid disorders include:

  1. Thyroid gland working overdrive and this leads to high levels of thyroid hormone.
  2. Thyroid gland not make enough hormone and this leads to low levels of thyroid hormone.
  3. Have a lump or nodule on the thyroid gland.

What does the thyroid gland do?

The hormones that the thyroid make have an important role in regulating numerous metabolic processes throughout the body.

Thyroid hormones talk to other parts of the body and regulate how the other parts of the body work such as heart, brain, gut, muscle, skin, bones and blood. For example, in the heart if the thyroid hormones are high they can make the heart go faster.

What are the types of thyroid hormone?

The thyroid gland uses iodine to produce the two different types of thyroid hormone called T3 (triiodothyronine) and T4 (thyroxine).  T4 is the main hormone produced by the gland.

After delivery throughout the body via the bloodstream, a small portion of the thyroxine (T4) released from the gland is converted to triiodothyronine (T3), which is the most active hormone.

The thyroid’s function is regulated by the brain's hypothalamus. When thyroid hormone levels are low, the brain produces a hormone that causes the pituitary gland to release Thyroid Stimulating Hormone (TSH). Since the thyroid gland is controlled by the pituitary gland and hypothalamus, disorders of these tissues can also affect thyroid function and cause thyroid problems.

What is the anatomy of thyroid gland

The thyroid gland is located below the adam's apple wrapped around the trachea (windpipe) in the front of the neck.

A thin area of tissue in the gland's middle, known as the isthmus, joins the two thyroid lobes on each side. It is butterfly-shaped.

Types of thyroid disorders?

The most common types of thyroid disorders are:

  • Hypothyroidism - The under-production of hormones by the thyroid gland

  • Hyperthyroidism - The over-production of a hormone by the thyroid gland

  • Goiter - Abnormal enlargement of the thyroid gland below the Adam's apple

  • Thyroid Nodules - A lump in the thyroid gland

  • Thyroiditis - Inflammation of the thyroid gland

  • Thyroid Cancer - A cancer of the thyroid gland

Although the effects of thyroid disorders can be unpleasant or uncomfortable, most thyroid problems can be managed well if properly diagnosed and treated.

What are the causes of thyroid disorders?

There are lots of different causes of thyroid problems. The potential cause depends on the particular type of thyroid disorder. The most common cause for thyroid problem is autoimmune problems. Normally the immune system targets bugs or infections. In autoimmune conditions the immune system is abnormal and attacks the normal cells in the body instead.

Causes of hypothyroidism?

There are different causes of hypothyroidism. The most common cause of hypothyroidism is:

  • Hashimoto's thyroiditis - this is an autoimmune condition where the body makes antibodies that destroy parts of the thyroid gland

Other less common causes are:

  • Post thyroidectomy - after the thyroid has been removed surgically the hormone levels can become low if they are not replaced adequately

  • Post radioiodine

  • Pituitary problems

  • Congenital hypothyroidism

  • Medications

  • Iodine deficiency

Cause of Hyperthyroidism?

There are different causes of hyperthyroidism. The most common cause of hyperthyroidism is

  • Graves' disease when the immune system produces an antibody that stimulates the entire thyroid gland; this leads to overactivity and higher levels of thyroid hormones.

Other causes are:

  • Toxic nodular goiter or toxic thyroid adenoma which are abnormal nodules of tissue in the thyroid that constantly produce thyroid hormones even when they are not needed.

  • Secondary hyperthyroidism is caused when the pituitary gland makes too much TSH, leading to over-stimulation of the thyroid gland

  • Thyroiditis or inflammation of the thyroid gland can cause transient hyperthyroidism

Who is at risk of thyroid disorders?

Both hypothyroidism or hyperthyroidism are common conditions that numerous people suffer from.

People at higher risk of thyroid disorders include those with:

  • Family history of thyroid problems

  • Family history of autoimmune problems

  • People with other hormone problems

  • People who have had previous radiotherapy to the neck

  • Females

  • Smokers

What are the symptoms of thyroid Disorders?

Thyroid Disorders can involve a changing metabolic rate.

  • Hair Loss - visible changes in their hair thinning

  • Skin Problems - uncharacteristically dry and patchy or more oily and acne-prone.

  • Weight Gain or weight loss

  • Unpredictable Bowel Function - Low thyroid levels creating a slower metabolism, a lazy gut and constipation.  With high thyroid levels some people may experience diarrhoea and/or frequent urge to defecate.

  • Swelling of the Neck - This may be due to inflammation or a lump in the thyroid

  • Menstrual Problems

  • Depression or Anxiety

  • Loss of Libido

  • Change in Sleep Patterns - Altered sleep patterns. sluggish and sleepy from hypothyroidism.  Alert and sleepless from hyperthyroidism.

  • Muscle and Joint Pain - Frequent aches and pains, muscle weakness that has no obvious explanation and carpal tunnel syndrome.

Diagnosis of thyroid Disorders

Tests that may be used to evaluate your thyroid include blood tests, radiology tests or biopsies. These tests are used to identify the characteristics of the thyroid disorder and what problems they are causing, specifically whether they are:

  • Enlarged nodules or goiters that can crowd around the wind pipe or gullet and make breathing or swallowing difficult

  • Cyst or fluid-filled nodules

  • Graves’ disease, which causes thyroid enlargement and hyperthyroidism

  • Hashimoto’s disease, where your thyroid is damaged by your immune system and hypothyroidism

  • Cancer or replicating abnormal cells

Pathology Tests

Blood tests are used to

  • Measure levels of thyroid hormones T3 & T4

  • Measure Thyroid Stimulating Hormone (TSH)

  • Measure thyroid antibodies levels

Radiology Tests

Imaging tests such as ultrasound, CT or MRI are used to

  • Work out the size of lumps or nodules in the thyroid gland

  • Visualize the consistency of the tissue within and around the gland

Imaging tests using radioactive iodine are used to

  • Review the function of thyroid nodules

Biopsy Tests

A fine needle biopsy uses a needle to aspirate (suck) some fluid from the thyroid gland.  By looking at a small part of the thyroid tissue under a microscope your doctor can tell if there are features suspicious for cancer.

Thyroid cancer

A Thyroid cancer can mean several things and the treatment can depends on the type and stage of the cancer.

Types of thyroid Cancer

  • Papillary (most common)

  • Follicular

  • Medullary

  • Anaplastic

Stages of thyroid Cancer

  • Tumor size

  • Has it spread or metastasized to other areas of the body or organs, namely the lungs, liver, and bones

  • Has the cancer spread to nearby lymph nodes

Treatments for thyroid disorders

Treatment depends on the diagnosis and nature of the disease. Common treatments include:

  • Medication

  • Radioiodine

  • Surgery

If thyroid levels are not treated and remain abnormal it can cause infertility, cognitive impairment, mood changes, weight change, gastrointestinal symptoms, neuromuscular dysfunction and problems with cholesterol.

Medication treatment for thyroid Disorders

Most patients with hypothyroidism will require lifelong thyroxine (T4).  People with hypothyroidism do not usually need to take T3 tablets.  This is because the body can naturally convert enough thyroxine (T4) in to triiodothyronine (T3).

It is important to take your thyroxine as recommended by your doctor.

  • Take thyroxine 30-60 minutes before eating

  • Calcium and iron supplements should not be taken within four hours of taking levothyroxine, because these supplements may decrease thyroid hormone absorption.

  • Thyroxine tablets should be kept in their original container and stored out of sunlight in a cool dry place

  • Do not continue taking a thyroxine preparation that it out of date

Some medications that may be used in hyperthyroidism include:

  • Beta-blockers: Used in hyperthyroidism to reduce the response of the body to the high thyroid levels and help decrease heart rate, tremor, nervousness and agitation

  • Antithyroid Drugs: Used in hyperthyroidism to block thyroid hormone synthesis

  • Iodine: Used in hyperthyroidism to inhibit the release of thyroid hormone from the overactive gland.  

Radioiodine treatment for thyroid Disorders

The thyroid gland and most thyroid cancers absorb iodine. Radioiodine can be used to destroy both normal and abnormal thyroid tissue.

Radioiodine is given usually as a pill.  Once inside the body the radioiodine is concentrated in the thyroid gland.  The radiation emitted from the radioiodine destroys the thyroid.

This treatment takes several months to work.  Sometimes it can be followed by hypothyroidism.

The dose of radioiodine used depends on the thyroid disorder:

  • Lower doses can be used in graves disease or in toxic multinodular goitre.

  • Higher doses may also be used for thyroid cancer.  The radioiodine can also be used to treat thyroid cancer if has spread to nearby lymph nodes or other parts of the body.

Thyroid Surgery (Thyroidectomy)

There are different types of thyroid operations that can be performed.  These include:

  • Total thyroidectomy - removing the entire thyroid gland

  • Hemithyroidectomy - removing half the thyroid gland

Reasons for thyroid surgery may include:

  • Removing a large goiter

  • Removing a nodule in the gland that is hyperfunctioning or working overdrive

  • Removing thyroid cancer

  • Graves disease

If the thyroid gland is removed entirely, then you will need to take thyroid hormone medicine for life.