The thyroid gland is the largest endocrine gland in the body. It is a butterfly shaped structure that is present in the front of the neck. It secretes thyroid hormone – also called thyroxine(T4). It also secretes a small amount of triiodothyronine (T3). The thyroid gland requires iodine to synthesize thyroid hormones. The thyroid hormones regulate the metabolic rate of the body. All the tissues in the body require thyroid hormone to function optimally.
The amount of T4 and T3 secreted by the thyroid gland is regulated by the pituitary gland, which lies underneath your brain. The pituitary secretes thyroid stimulating hormone – TSH , which stimulates the thyroid gland to secrete T3 and T4. The pituitary senses the level of thyroid hormones in the blood, and maintains thyroid secretion in the normal range. If thyroid hormone level drops even a little the pituitary reacts by increasing the amount of TSH secreted.
Thus T4 and T3 levels are more important in thyroid disease management and treatment. Check more thyroid conditions and diagnosis methods below
What are the symptoms of hypothyroidism?
The thyroid hormones are necessary for optimum functioning of almost all the tissues of the body. A decrease in the level of thyroid hormones, therefore result in a general slowing down of the body. Some of the symptoms seen with hypothyroidism tiredness
- dry and coarse skin, hair fall
- hoarse voice
- muscle weakness, cramps and aches
- Inability to tolerate cold
- pins and needles in the fingers and hands (carpal tunnel syndrome)
- heavier and longer periods
- weight gain
- swollen or puffy face
- low mood or depression
- memory problems
- difficulty in concentration
How are thyroid problems diagnosed?
Problems due to increased or decreased functioning of the thyroid gland are diagnosed by performing blood tests called thyroid function tests.
TSH (thyroid stimulating hormone) is the test which is initially done. It is increased in patients with hypothyroidism and decreased in patients with hyperthyroidism. Normal ranges for adults are between 0.2 to 5 mU/L. In pregnancy the reference ranges are lower, with cutoffs depending on the stage of pregnancy.
Tests for total T4 levels, free T4 levels, and T3 may be done if TSH is lower than normal in order to look for hyperthyroidism.
How is hypothyroidism diagnosed?
Hypothyroidism is diagnosed on the basis of an increased TSH level. Unequivocally high levels indicate hypothyroidism and treatment is started directly.
Patients with borderline TSH levels are said to have subclinical hypothyroidism. Your doctor may ask for a thyroid antibody test and tests for levels of T4, T3 in order to determine the need for treatment.
How is hyperthyroidism diagnosed?
A low TSH with high T4 and T3 suggest thyrotoxicosis (overactive thyroid). Your doctor will advise further tests in order to differentiate between different causes of thyrotoxicosis.
What is the treatment for hypothyroidism?
Patients are given levothyroxine tablets in order to compensate for the decreased hormone production by the thyroid. The dose of levothyroxine depends on the blood test reports and the age and weight of the patient. This tablet needs to be taken on an empty stomach. A gap of 30 to 45 minutes between the medication dose and your morning meal will ensure complete absorption.