Glossary On What is Hyperthyroidism?

About the Thyroid gland

The thyroid gland is a small butterfly-shaped gland located in the neck region and it weighs about 20 to 25 grams in an adult. The thyroid gland takes up the iodine from the foods we eat and converts it into hormones namely Thyroxine (T4), Tri-iodothyronine (T3) Calcitonin. The levels of thyroid hormones are in turn controlled by TSH (Thyroid Stimulating Hormone/ Thyrotropin) that is secreted by another gland called Pituitary which is situated in the brain.

Thyroid hormones are instrumental in growth and development of the body and also control the way body utilizes energy. Besides these, thyroid hormones also affect the functioning of brain, nervous system and heart; regulate body temperature, skin hydration, muscle strength, body weight, menstrual cycles, etc.

What happens in Hyperthyroidism?

When the thyroid gland starts producing more than the required quantities of thyroid hormones, the patient ends up having 'too much of thyroid hormones' circulating in the blood. This condition is called hyperthyroidism and can be caused due to various factors ranging from excess iodine intake to infection of the thyroid gland to excess stimulation by the pituitary gland.

Normal hormone levels:

T3 (Tri-iodothyronine): 80-220 nanograms/dl
T4 (Thyroxine): 4.5 to 12.5 micrograms/dl
TSH (Thyroid Stimulating Hormone): 0.5-6 micro International units/ml

Hyperthyroidism can have widespread consequences on the body since the excess hormones speed up the normal body metabolism resulting in numerous symptoms like excess hunger yet losing weight, intolerance to heat, tremors, hyperexcitability, anxiety, fatigue, etc.

Hyperthyroidism can occur at any age though it tends to have a peak incidence during 20 to 40 years of age. It’s almost 5 to 10 times more common in women as compared to men. The overall incidence of this condition is between 0.05 to 1 %.

A large number of cases are diagnosed with subclinical hyperthyroidism wherein the patient has no apparent symptoms of hyperthyroidism but abnormal levels of thyroid hormones are detected in laboratory tests.

A sudden worsening of hyperthyroid state may lead to a crisis condition called Thyrotoxicosis (also known as Thyroid storm). Thyrotoxicosis is not very common but can be life threatening and requires immediate medical attention whenever it does occur.