The thyroid gland is the biggest
gland in the neck. It is situated in the anterior (front) neck below the skin
and muscle layers. The thyroid gland takes the shape of a butterfly with the two
wings being represented by the left and right thyroid lobes which wrap around
the trachea. The sole function of the thyroid is to make thyroid hormone. This
hormone has an effect on nearly all tissues of the body where it increases
cellular activity. The function of the thyroid therefore
is to regulate the body's metabolism.
Through the hormones it produces, the thyroid gland
influences almost 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.
effects can be unpleasant or uncomfortable, most thyroid problems can
be managed well if properly diagnosed and treated.
What Causes Thyroid Problems?
All types of hyperthyroidism are due to an
overproduction of thyroid hormones, but the condition can occur in
- Graves' disease: The production of too much thyroid
- 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 few weeks but may
persist for months
- Pituitary gland malfunctions or cancerous growths in the
thyroid gland: Although rare, hyperthyroidism can also develop
from these causes.
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
- Hashimoto's thyroiditis: In this autoimmune disorder, the
body attacks thyroid tissue. The tissue eventually dies and stops
- Removal of the thyroid gland: The thyroid may have been
surgically removed or chemically destroyed.
- Exposure to excessive amounts of iodide: Cold and sinus
medicines, the heart medicine 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
Untreated for long periods of time, hypothyroidism can
bring on a myxedema coma,
a rare but potentially fatal condition that requires immediate hormone
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
is unusually inactive and quiet, has a poor appetite, and sleeps for
excessively long periods of time.
Cancer of the thyroid gland is quite rare and
occurs in less than 10% of thyroid
nodules. You might have one or more thyroid nodules for several
years before they are determined to be cancerous. People who have
treatment to the head and neck earlier in life, possibly as a remedy
tend to have a higher-than-normal risk of developing thyroid