Thyroid malfunction is usually due a problem called autoimmunity which has a genetic basis. Antibodies are produced by our body to fight against infections. These antibodies act against the thyroid and alter its structure and function (Autoimmunity). As a result the thyroid gland commonly becomes underactive, but rarely can become overactive too. Contrary to the popular belief, iodine deficiency does not play a significant role except in some pockets of the country. Rarer causes include congenital problems of thyroid development, drugs and infections.

Since the thyroid hormone affects the function of all organs of the body, symptoms do not pertain to a particular system or organ. Most often the symptoms are vague like tiredness, generalized weakness etc. and a high index of suspicion is required to diagnose the problem. The following are some of the common symptoms of hypothyroidism:

• Fatigue
• Frequent, heavy menstrual periods
• Forgetfulness
• Weight gain
• Dry, coarse skin and loss of hair
• Hoarse voice
• Intolerance to cold
• Remember excessive weight gain is usually not due to thyroid disease!

The diagnosis of an under active thyroid gland involves a thorough physical examination, an appropriate blood test and a physician experienced in interpreting the result. This commonly involves the estimation of 2 hormones, T4 (Thyroxine) and TSH (Thyroid stimulating hormone). In the commonest form of hypothyroidism T4 is low or normal with a high TSH.

The principle of treatment is replacing the deficient thyroid hormone. This is done by administering thyroid hormone (thyroxine) in a tablet form taken in empty stomach. Dietary restrictions like avoidance of certain vegetables like cabbage, cauliflower etc are usually not recommended. Periodic monitoring with blood tests (T4 and TSH) is necessary for adjusting the dose.

An overactive thyroid gland (otherwise called hyperthyroidism) is a less common problem. This problem is most commonly due to autoimmunity, but occasionally may be due to autonomously functioning thyroid nodules.

The following are the common symptoms of hyperthyroidism: .

• Irritability/nervousness or anxiety
• Muscle weakness/tremors
• Infrequent, scant menstrual periods
• Weight loss
• Sleep disturbances
• Enlarged thyroid gland
• Vision problems or eye irritation or protrusion of eyes
• Heat sensitivity

Swelling and protrusion of the eyes (Thyroid eye disease) is a common accompaniment of hyperthyroidism and may rarely be the only manifestation.

The diagnosis of an over active thyroid involves a thorough physical examination by doctor along with a blood test. Special thyroid gland scans(Thyroid uptake scan) is usually necessary to plan treatment.

The treatment options include medications (carbimazole or prophylthiouracil), radioactive iodine to destroy the overactive thyroid tissue or rarely surgery. Treatment decision is done on an individual basis depending on individual circumstances. Regular follow up is needed.

Thyroid nodules are swelling in the thyroid gland (goitre). They may be single or multiple. Few clues which may suggest malignancy include rapidly enlargement of the nodule, hoarseness of voice and breathing or swallowing difficulty. The most important step in the management is to know whether these are malignant or benign. This most vital test is FNAC (Fine Needle Aspiration Cytology) wherein a needle is put into the thyroid nodule and the cells are aspirated and analyzed. The next step i.e whether the nodule or the whole gland needs surgical removal depends on the result. Accessory tests like ultrasound of the neck and technetium scan of the thyroid gland are done to guide the treatment decisions. Fortunately, majority of the nodules of the thyroid are benign and do not require surgical removal.

Endocrinologists are the doctors trained to diagnose and treat all thyroid problems.