Structure and Function
of the Thyroid
Iodine Deficiency Goiter
- Treatment of Hyperthyroidism
The situation in Europe has shown that approximately
10% of the population has an enlarged thyroid gland (goiter). With age,
this rate increases to even 40-50%. Of these 40-50%, a number could
have been helped if they had received treatment early enough. Many of
the operations that are performed year for year could have been avoided.
The rate of hyperthyroidism incidence in Europe amounts to several hun-dred
thousand per year.
Structure and Function
of the Thyroid
The word thyroid stems from the Greek word thureos
and means oblong shield. As the name implies, the thyroid is situated
like a shield before the trachea. It is butterfly-shaped and weighs
up to 19 grams in women and up to 25 grams in men.
The thyroid gives off its secretion inwardly, into
body tissue and from there into the bloodstream. These secretions are
called hormones. Thyroid hormones are indis-pensable. A critical component
of hormones is iodine, which is taken up via water and food. From iodine
and protein building blocks, the thyroid produces triiodothyron-ine
and thyroxine, or T3 and T4 for short. These hormones are released into
the body as needed.
Hormones stimulate development and growth, step up
metabolic processes and en-ergy conversion and are of great significance
to mental development and the devel-opment of the central nervous system.
In short: a loss of function slows down physical and mental life processes,
and an increase in function speeds them up.
The population in Europe consumes just 1/3 of the recommended
dosage of iodine. The recommendation calls for 150-300 micrograms. In
times of hormonal transition such as puberty, pregnancy or menopause,
the required amount is even higher. Therefore, in part due to their
monthly menstrual cycles, women are affected 3 times more often than
It is easy to increase iodine intake
You should only use iodised salt in your household. As industrially
prepared food-stuffs are not usually seasoned with iodine table salt,
domestic intake is not enough to provide the body’s daily allowance.
Moreover, high sodium intake entails the risk of high blood pressure
and associated circulatory disorders.
The most important source for increasing iodine intake
is saltwater fish (ocean perch, pollock, mackerel, cod); i.e. not freshwater
fish such as trout for example. The con-sumption of one portion of saltwater
fish twice a week means saying goodbye to worries of iodine deficiency.
As far as possible, you should make sure that the fish you eat is fresh
or frozen, as processed fish products contain hardly any iodine. Frying
destroys less iodine than cooking.
Classification of the degree of severity of iodine deficiency on the
basis of io-dine excretion in urine (WHO)
||excretion of 50-150 g iodine/g creatinine
||excretion of 25-50 g iodine/g creatinine
||excretion below 25 g iodine/g creatinine
An iodine deficiency of grade I or grade II is prevalent in Europe.
Iodine Deficiency Goiter
Iodine deficiency goiter occurs, as the name already
indicates, from a lack of iodine. If not enough iodine is available,
no thyroid hormone can be produced. As a result, the level of this hormone
in the blood drops. This deficiency is then reported back to the brain
with the message that the thyroid needs to actively produce more hormones
for the metabolism. To confront this situation, the thyroid grows in
order to be able to exploit the last bit of iodine left in the body.
Thus, in the event of too little iodine, too much tissue is the result.
That means that when faced with the presence of a sus-tained state of
iodine deficiency, the thyroid attempts to compensate for this condition
Categorisation of goiter size on the basis of palpitation findings
according to the recommendation of the WHO
||not visible when bending head back
||visible when bending head back
||visible goiter when neck is in a normal position
||very large goiter, visible even from a distance
How long a goiter grows will depend on the degree of
iodine shortage and to what extent iodine deficiency forces the thyroid
to grow. However, the body defines individually when a state of iodine
deficiency is reached and when not. The ability of cells to absorb iodine
differs from person to person. A goiter can be present for many years
before any dysfunction occurs. Left untreated, a goiter almost always
leads to hyperthyroidism.
If too many thyroid hormones are produced in the thyroid, the body
can become flooded with thyroid hormones, signalling the onset of the
condition : thyroid hyperfunction (Hyperthyroidism).
These symptoms may occur due to hyperthyroidism:
|increase in appetite
|increase in heart rate
|frequent bowel movements
|heat intolerance, moist skin
Rapid, at times irregular pulse, slightly elevated blood pressure.
The skin is warm and velvety. Patients sweat a lot and prefer colder
rooms. Afflicted persons tend to dress lightly. Nails break easily and
increased hair loss is noted during brushing. The hair is silky soft
and “doesn’t lay right”.
Tendency to diarrhoea or frequent bowel movements. Stool that was once
firm becomes soft.
Musculature and skeletal system:
Moderate grade osteoporosis is possible, muscular weakness, muscle aches
Hormonal system and metabolism:
Menstrual disorders, decrease in libido and potency. In the event of
insufficient treatment during pregnancy, there is a risk of miscarriage,
premature birth or birth defects.
Patients become nervous. They have difficulty controlling their emotions.
Restless, unmotivated movements and sleeping disorders are common. The
irritability can build up leading to serious psychotic states.
Often there is presence of thyroid enlargement, or a goiter forms simultaneously
with onset of the hyperfunction. However, there may be a lack of visible
With Graves’ disease, watery eyes, foreign body eye sensation,
photosensitivity, redness and protrusion of the eyes may occur.
Hyperthyroidism can be the manifestation of thyroid
segments which have liberated themselves and separated from tissue,
thus becoming autonomous. However, it can also be caused by Graves’
disease. On the whole, these two diseases account for 95% of all hyperthyroidism
Causes of Hyperthyroidism
|immunethyreopathy (Graves’ disease)
|hormone production outside the thyroid: e.g. carcinomatous metastases
|hyperthyroidism caused by external influences: e.g. caused by
The term autonomy refers to the independency of certain functions from
regulative influences. In the thyroid, cells defy regulation and uninhibitedly
produce hormones. These cells become “nodules” which overheat
due to overactive production. Autonomy can occur as single nodules (unifocal
autonomy or autonomous adenoma), in the form of multiple nodules (multifocal
autonomy) or as scattered cell heaps (disseminated autonomy). Although
autonomy does tend to develop more prevalently in older goiters, it
can still be found in normalsized thyroids. Hence, even people without
goiters are not safe from thyroid hyperfunction caused by autonomy.
If autonomy is not the cause of the overactive thyroid, then the signs
point to the presence of Graves’ disease. Graves’ disease
is a socalled autoimmune disease: Thereby various defence proteins (antibodies)
of the body’s own police force (immune system) are formed to attack
the cells of the thyroid. This means that the im-mune system, which
usually protects against disease entering the body from the out-side,
itself becomes a link in the chain of destructive events. The thyroid
“thinks” that the antibodies are thyroid-stimulating hormones
(TSH) and begins to produce hor-mones. This leads to a hyperfunction.
In 60 % of all cases, patients with Graves’ disease have greatly
protruding eyeballs. Through the lymphatic system, these defence proteins
infiltrate into the depths of the eye orbits. Here as well, autoimmune
processes take place. In rare cases, a third area can become affected:
the main front sections of the lower legs. Scientists still do not know
why the body’s own immune system suddenly attacks itself. The
cause of the disease is probably genetic on the one hand, but mental
and hormonal processes seem to also play a role on the other hand.
The most common symptoms in Graves’ disease are
of a mental nature.
Treatment of Hyperthyroidism
As an autoimmune disorder, Graves’ disease tends to heal itself.
In order to bridge the time until the degeneration of disease processes,
medical therapy is expedient. Therefore, thyreostatic long-term therapy
is the treatment of choice for Graves’ disease. The duration of
its existence is of key significance to the selection of the optimal
form of therapy. Patients with “fresh” onset of hyperthyroidism
will be treated with medicine as a general rule. If there are still
indications after 1-2 years of the persistence of hyperthyroidism, then
a surgical therapy form should be considered. Antithyroid drugs are
thyroid inhibitors which curtail hormone production by preventing the
thyroid from absorbing iodine.
Autonomy does not regress under the influence of antithyroid
drugs. In this respect, as a rule, the thyreostatic therapy serves as
a preparation to a definitive therapy in this case (operation or radioiodine).
Thyroid inhibitors curtail the production of hormones,
but have no influence on those hormones that have already been produced
and are “in storage”. Therefore, delayed effects are to
be expected. For a while, from one up to three weeks time, the unset-tling
symptoms will persist. At times, tranquillisers are also prescribed
along with thyroid medicines. The initial dosage is adjusted according
to the patient and the active ingredient in the thyroid inhibitor. If
symptoms normalise after approximately 4 weeks, dosage will be reduced
to a minimal so that the thyroid is not completely incapacitated.
Pregnancy and Breastfeeding
Maternal hyperthyroidism during pregnancy can be associated with an
increased rate of miscarriage and birth defect. During the 10th –
14th week of pregnancy, foetal hormone production commences. Thence,
the dosage of antithyroid medicine must be kept as low as possible.
In the last trimester of pregnancy, hyperthyroidism often improves spontaneously.
During lactation, iodine therapy is only good for iodine
deficiency goiter. However, thyroid inhibitors are passed into the breastmilk.
Therefore, the antithyroid drug propylthiouracil is the treatment of
choice, as its concentration in milk amounts to a maximum of one-tenth
of the maternal blood serum concentration.
Nevertheless, gynaecologists, thyroid specialists and
paediatricians should work together in this matter.
Effects of Therapy
If the treatment of hyperthyroidism was successful, hormone production
slows down, the metabolism normalises and the body can put on weight
again. At times, the patient will put on more weight than before, as
the patient’s eating habits are still tailored to the increased
It should also be kept in mind that once muscle weakness
is present, time is needed for the body to get back to its original
strength. Therefore, immediate bounciness is not to be expected.
Peace and Quiet
An overactive thyroid can be countered with peace and quite. Sleeping
and going for quiet walks has a positive effect on patients. A great
deal of understanding is required from family members, as on the outside
patients appear to be normal. However, on the inside a storm is still
raging. Moreover, patients should avoid sunbathing and sports. Naturally,
smoking is one of the things that should be avoided.
Avoidance of Iodine
Iodine-containing foods are taboo in the event of hyperthyroidism. Seafood
should not be a part of the patient’s diet. However, if nutrition-based
iodine deficiency was the cause of the disease, this will certainly
not be a problem.
For over 50 years, millions have undergone radioiodine therapy across
the globe by now. Radioactive iodine is absorbed preferentially by hormone
cells whose metabolic rate has increased. In the case of Graves’
disease, all cells are affected and diseased sections are reached in
the event of autonomy. This way, inopportune thyroid tissue is deactivated
cleanly, thoroughly and without complication, thus eliminating hyperthyroidism.
Irradiation takes place on site and is limited to this site. An individual
dosage can be determined which is oriented to the motto “as little
as possible, as much as necessary.” The surrounding tissue is
not exposed, therefore receiving no damage. For purposes of irradiation
protection, therapy is conducted on an inpatient basis. Therapy takes
a little bit longer because radioiodine treatment is very thorough.
Effects begin to unfold after 4 weeks time. After this point, care should
be taken to rule out hypothyroidism.
Today, thyroid operations rank number 3 on the most frequently performed
operation list, following appendicitis and hernia operations. Surgery
is performed on larger goiters, which, for example, block the windpipe,
or in the event of nodular changes. Some nodules no longer absorb iodine,
making radioiodine therapy ineffective. Surgery is only performed after
the metabolism has been stabilised through drug treatment. This is the
fastest way for the patient to rid himself of hyperthyroidism. Thyroid
removal or removal of all but a small remainder of the thyroid can cause
hypofunction, which would have to be treated with thyroid hormone tablets.
However, the following holds true: it is better to have a healthy individual
with an underactive thyroid than a mentally disturbed person with hyperfunction.
As opposed to hyperfunction, with thyroid hypofunction,
the body has too little thyroid hormone available to it. Causes of this
are congenital, stimulated by inflammation or extreme Iodine deficiency
Thyroid hypofunction (hypothyroidism) develops gradually.
As all body cells are de-pendent on thyroid hormones, effects of the
shortage thereof spread out throughout the entire body. More than 2/3
of patients complain of less efficiency, weakness, lethargy, fatigue,
chills, constipation and loss of memory. The overall scaled-down metabolism
coupled with physical inactivity at the same level of food intake leads
to patients becoming overweight. Further physical findings are manifested
as oedema. Excess water causes swelling of the eyelids. The fingers
become fat. The skin becomes dry and pale and even patchy at times.
Treatment of Hypothyroidism
As hypothyroidism is the effect of a lack of hormones,
therapy consists of administering thyroid hormones such as thyroxine
(T4). The synthetic made hormone is identi-cal to the body’s own
so that no side effects can be expected if the proper dosage is given.