The thyroid gland (glandula thyreoidea)
is a hormone gland in the larynx in the neck.
It produces thyroid hormones which contain iodine:
triiodothyronine (T3)
and tetraiodothyronine, also known as thyroxine (T4).
These hormones play an important part in human metabolism
and help to regulate a number of bodily functions.
In fetuses, newborns and children
these thyroid hormones are essential for growth and maturation of the body.
If the thyroid gland stops working properly
it may produce too many hormones or not enough.
Either type of disruption to hormone production
can cause numerous problems.
If the thyroid gland does not produce enough hormones
this is referred to as hypothyroidism.
Low levels of thyroid hormones slow down metabolism
which can cause, for example,
listlessness,
sensitivity to cold,
weight gain or constipation
or depression.
Hypothyroidism (underactive thyroid) is frequently caused
by Hashimoto’s thyroiditis.
This is an autoimmune disease where the body’s defense system
mistakenly attacks the cells of the thyroid gland.
This causes chronic inflammation of the thyroid gland.
Hypothyroidism responds well to treatment with drugs
containing the active ingredient levothyroxine (L-thyroxine)
which replaces the body’s own hormone thyroxine (T4).
The symptoms usually clear up completely when treated.
Depending on the cause, treatment of hypothyroidism
may be temporary or may be lifelong.
If the thyroid gland produces too many hormones
this is referred to as hyperthyroidism or overactive thyroid.
Hyperthyroidism makes many bodily functions work continuously “flat out”.
It can be detected by symptoms such as
weight loss, sweating, nervousness or heart palpitations.
This means that hyperthyroidism also increases the risk
of certain cardiovascular diseases.
The commonest cause of hyperthyroidism
is Basedow’s disease.
This again is an autoimmune disease.
However in this case the immune system produces antibodies
that activate the thyroid gland and make it grow.
This results in overproduction of hormones.
Mild hyperthyroidism
can occasionally clear up even if untreated.
In most cases, production of excess hormones in the thyroid gland
is initially slowed down by administering tablets
known as “thyreostatics”.
Long-term use of thyreostatics
can restore normal thyroid function in people with Basedow’s disease.
If this does not work
parts or all of the gland is surgically removed
or treated with radioactive iodine.
Radioactive iodine therapy involves administering radioactive iodine
which accumulates in the thyroid gland
and destroys the overactive cells.
If hyperthyroidism is not properly treated
the people affected may develop cardiovascular diseases
such as atrial fibrillation.
Over the long term it may accelerate bone remodeling
leading to osteoporosis (weak bones).
A blood test can shed light
on whether existing symptoms are caused by a thyroid gland disorder
or a precursor to such a disorder.
In short:
The thyroid gland is a hormone gland
that regulates metabolism and many bodily functions
through its thyroid hormones.
Hypothyroidism (underactive thyroid), which shuts down the metabolism
and is associated particularly with fatigue and being overweight,
is frequently caused
by the autoimmune disease Hashimoto’s thyroiditis.
It can be treated with drugs
to replace the missing thyroid hormone T4.
Hyperthyroidism (overactive thyroid)
is most commonly caused by Basedow’s disease
where the thyroid gland is enlarged and permanently activated.
People with hyperthyroidism sweat quickly,
are nervous and have heart palpitations.
If hyperthyroidism does not clear up by itself
tablets are prescribed to slow down hormone production
and return it to normal levels in the long term.
If this does not work thyroid gland tissue must be removed
or destroyed by radioactive iodine therapy.