Hypothyroidism is a very common ailment which is found more commonly in women and keeps growing with the age. Every 3 to 5 % of the population is suffering from hypothyroidism.

Some of the common causes resulting hypothyroidism in adults are as follows:

In this form of hypothyroidism, the immune system of the human body attacks the thyroid tissues. As a result, the thyroid gland enlarges and its ability to form thyroid hormones reduces. This kind of hypothyroidism is mostly found in women in a proportion of about 5 to 10 times more than men. Hashimoto’s Thyroid is recognized as the autoimmune disease and usually the patients of hashimoto thyroid suffer from one or more autoimmune diseases like diabetes or pernicious anemia. The identification of the disease can be made by detecting the anti-TPO antibodies present in the blood or by conducting a thyroid scan.

It causes inflammation in the thyroid gland and occurs due to the type of white blood cell called lymphocyte. This form of thyroid, large amount of thyroid hormone leaks out of the inflamed gland. The ailment generally develops after the pregnancy. About 8 % of women suffer after the delivery.
The patients suffering from hyperthyroid condition such as graves diseases are treated with the radioactive iodine. As a result of such treatment, they are left with a minimal or relatively zero functioning of thyroid tissue thereafter. It depends on large number of factors involved in the treatment like the dose of iodine provided as per the size and the activity of the thyroid gland. If no significant activity of the thyroid gland takes place within the 6 months after the radioactive treatment then it is assumed to be silent with no functioning. Also the hypothyroidism is followed by the removal of thyroid gland as a result of surgery.

The pituitary gland or the hypothalamuses are not able to function properly with the production of reduced levels of T4 and T3 circulations, even though the thyroid gland is normal. This ailment is also called as tertiary hypothyroidism.

It may occur if the patient had undergone brain surgery or due to the less amount of blood supply in the brain. In such cases the TSH as generated by the pituitary gland becomes deficient with the low blood levels of TSH. Hypothyroidism is caused because the pituitary TSH is not being stimulated by the Thyroid gland. The ailment occurs in association with the other hormone deficiencies as pituitary regulates the other processes of growth, reproduction and adrenal function.

• Medications
Medications are being used to cure over-active thyroid actually result in hypothyroidism. These drugs constitute methimazole (Tapazole) and propylthiouracil (PTU). The other medication includes the use of psychiatric medication called lithium (Eskalith, Lithobid) that is being considered as the cause for hypothyroidism. Also the drugs having large amount of iodine in it like amiodarone (cordaron), potassium iodide (SSKI) and Lugol’s solution may result in the changes in the thyroid function resulting in the low blood levels of thyroid hormone.