GOITRE

GOITRE

A goitre can be described as an enlargement of the thyroid gland.
This gland is situated at the front of the throat, below the

Adam’s apple (larynx). It comprises two lobes that lie on either

side of the windpipe and are joined in front by an isthmus. The

thyroid gland secretes hormones to regulate many metabolic

processes, including growth and energy expenditure. The thyroid

gland is controlled by the pituitary gland, which is located in

the brain. The pituitary prompts the thyroid to make its hormones

- including thyroxine (T4) and tri-iodothyronine (T3) - by

releasing thyroid-stimulating hormone (TSH). However, the thyroid

can’t manufacture its hormones without sufficient dietary iodine.

If a person’s diet is low in iodine, the pituitary keeps sending

chemical messages to the thyroid, but in vain. The thyroid gland

enlarges as it attempts to comply with the pituitary’s demands.

Apart from iodine deficiency, other causes of goitre involve

conditions of the thyroid - such as nodules, cancer,

hyperthyroidism and hypothyroidism.


TYPES OF GOITRE

Goitres are broadly classified into TWO groups including:

    ENDEMIC GOITRE -  which affectS a whole community through

insufficient dietary iodine. This is caused by lack of iodine in

the soil in which foods are grown. An example is Australian

Capital Territory with low iodine levels in the soil.    iodine

deficiency are found in cities like Melbourne and Sydney.

Mountainous areas and areas far from the sea are the ones most

likely to be iodine deficient. Endemic goitres tend to be more

prevalent in developing countries. They are rare in developed

countries because of widespread iodine supplementation.
   

SPORADIC GOITRE- is one which only the individual is affected.

Risk factors for sporadic goitre include family history, diet, age

(over 40 years) and gender (women are more susceptible than men).


SYMPTOMS

Goitre symptoms include:

1) Enlargement of the throat, ranging from a small lump to a huge 

   mass.

2) Swallowing problems, if the goitre is large enough to press on 

  the oesophagus.

3) Breathing problems, if the goitre is large enough to press on

the windpipe (trachea).


CAUSES OF GOITRE

Goitre can be caused by a range of factors, including:

1) Insufficient iodine in the diet.
2) High consumption of certain foods that neutralise iodine, such

as cabbage, broccoli and cauliflower. Other foods, like soy, may

also induce goitres.
    Certain drugs, such as lithium and phenylbutazone.
    Thyroid cancer.
    Nodules growing on the thyroid gland.
    Hyperthyroidism (overactive thyroid gland).
    Hypothyroidism (underactive thyroid gland).

OTHER CAUSES ARE


Hyperthyroidism - which means the thyroid gland is overactive. A

common cause is Graves’ disease, in which the immune system

produces antibodies that act like TSH and stimulate the thyroid

gland uncontrollably. The gland responds by producing an excessive

amount of hormones. The goitre is caused by this massive

overstimulation.
Hypothyroidism

Hypothyroidism means the thyroid gland is underactive. The

pituitary gland keeps sending its chemical messages, instructing

the thyroid to produce its hormones. The thyroid gland enlarges as

it attempts to comply.

Thyroid nodules

Thyroid nodules are lumps that grow on the gland. Nodules are

classified into two groups:

    Hot or warm - these nodules account for around 15 per cent of

cases, and can cause hyperthyroidism. The cancer risk is low.
    Cold - these nodules account for around 85 per cent of cases.

Around 20 per cent of these are cancerous.

Thyroid cancer

Sometimes, the thyroid gland is enlarged because of cancer. Anyone

can develop thyroid cancer, regardless of age or gender. The

incidence rates are very low and the cure rate is very good.

RISK FACTORS

 Chronic goitre - persistent enlargement of the thyroid gland.
 Family history - a susceptibility to thyroid cancer can be 

inherited.
 Gender - more women than men develop thyroid cancer.
 Radiation exposure - high doses of radiation were used during the

 1950s to treat disorders of the throat and skin.

Diagnosis methods

    Physical examination
    Blood tests - to check for thyroid hormone levels and    

particular antibodies
    Ultrasound scan
    Fine needle biopsy
    Radioactive iodine scan.

Treatment options

Treatment depends on the cause:

1) Goitre caused by iodine deficiency - can be helped with the

introduction of iodine-rich foods into the diet, such as seafood

and iodised salt.
2) Hyperthyroidism - is managed with drugs that slow the activity

of the thyroid. If these fail to work, part or all of the thyroid

gland is surgically removed. Alternatively, some or all of the

thyroid’s hormone-producing cells can be destroyed with

radioactive iodine treatment.
3) Hypothyroidism - is treated by lifelong hormone replacement

therapy.
4) Benign thyroid nodules - are shrunk with medications, destroyed

with radioactive iodine treatment or surgically removed, depending

on the type.
4) Cancer of the thyroid - is treated by surgical removal of the

gland, followed by radioactive iodine treatment.



IMPORTANT NOTE

    A goitre is an enlargement of the thyroid gland.
    Causes include iodine deficiency, hyperthyroidism,

hypothyroidism, thyroid nodules and thyroid cancer.
    Treatment depends on the cause.