Hypothyroidism refers to the condition resulting from deficiency of thyroid hormones.

Symptoms of Hypothyroidism
Tiredness, depression, mental showing, excess sleep, laziness, body ache, tingling, cramps, swelling, thickening and drying of skin, hair loss, weight gain, decreased appetite, feeling of cold, constipation, hoarseness of voice, impotence, changes in menstrual flow, failure to conceive and goiter may result from hypothyroidism in adults, in children, in addition, growth and sexual development as well as school performance are affected. In new born, hoarse cry, large tongue, distended abdomen, hernia through the umbilicus, prolonged jaundice, loose muscle tone may be seen. All complaints need not be present in a given patient. In fact, quite often, the patient has no complaint.

Causes of Hypothyroidism
Hypothyroidism can result from several causes:

1. In adults, the commonest cause of hypothyroidism is thyroid shrinkage and failure resulting from production in the body of certain substances called antibodies against the thyroid. This tendency of the body to produce antibodies, against its own tissues may run in families. In such an individual, antibodies against other body tissues may be produced leading to other disorder like white skin patches, childhood diabetes, certain types of anemia, arthritis etc.
2. In some situations where antibodies are produced, the thyroid may not shrink but actually increase in size (goiter) to compensate for its failing function.
3. As iodine is necessary for production of thyroid hormones, iodine deficiency due to poor dietary iodine intake leads to hypothyroidism.
4. If Inflammation of the thyroid glands as after infection or delivery can deplete the thyroid glands of its hormones over a period of time leading to hypothyroidism.
5. Certain drugs and radiation can lead to hypothyroidism. It is important to tell us details of all drugs (allopathic, ayurvedic etc.) that the patient is taking.
6. Deficiency of certain enzymes essential for thyroid hormone production can lead to hypothyroidism. This deficiency can run in families.
7. Absence of thyroid gland at birth leads to hypothyroidism since birth.
8. Disorders leading to decreased TSH secretion from the pituitary gland in the brain lead to hypothyroidism.
9. Certain drugs and radiation can lead to hypothyroidism. It is important to tell us details of all drugs (Allopathic, ayurvedic etc.) that the patient is taking.
10. Deficiency of certain enzymes essential for thyroid hormone production can lead to hypothyroidism. This deficiency can run in families.
11. Absence of thyroid gland at birth leads to hypothyroidism since birth.
12. Disorders leading to decreased TSH secretion from the pituitary gland in the brain lead to hypothyroidism.

Tests for presence of hypothyroidism

1. All newborns should be tested for presence of hyperthyroidism. Hypothyroidism is the commonest treatable cause of mental retardation. If untreated even for a few days or weeks, they hypothyroid new born will life long mental retardation.
2. All individuals with a family history of thyroid disorders.
3. All individuals suffering from disorders resulting from production of antibodies against one or more tissues. Examples of such disorders are childhood diabetes, white skin patches (vitiligo), certainly of anemia, rheumatoid arthritis etc.
4. All individuals who have one or more complaints suggestive of hypothyroidism (see above).
5. All women within first year after delivery particularly if they have persistent cramps, body aches, depression, tiredness, goiter or a positive family history.
6. All individuals with psychiatric disorders especially depression or psychosis.
7. All individuals detected to have persistent anemia.
8. All individuals over 70 years of age, particularly females.

Diagnosis of Hypothyroidism
Hypothyroidism is diagnosed by estimating the blood levels of thyroid hormone and TSH. As the levels in blood are extremely minute, accurate and reliable methods of estimation are of utmost importance. In the majority of the cases, hypothyroidism is indeed lifelong. However, hypothyroidism that occurs after certain drugs or after inflammation as after infection or delivery may be temporary.

Treatment of Hypothyroidism
Treatment of hypothyroidism is replacement treatment i.e. the deficient thyroid hormone is replaced externally in tablet form. The treatment does not cause the non–functioning thyroid to resume its function. Except a few cases where hypothyroidism is temporary, the treatment is hence lifelong. The medicine is given as a single dose with water, on empty stomach first thing in the morning and at least 30 minutes before breakfast. Usually, a small dose is started initially and is gradually increased after a couple of weeks. Under treatment will cause inadequate replacement of the deficient thyroid hormone and hence complaints will persist. On the other hand, over treatment may cause irritability, sense of heart beating fast or irregularly, tremors etc. More importantly, it can deplete the bones of calcium and make them take the minimum essential dose of thyroid hormone in hypothyroidism.

Certain complaints like puffiness and weight generally improve in a couple of weeks. Thereafter, improvement in appetite and constipation occur. some complaints like hoarseness of voice, changes in skin and and hair require several months to disappear. The abnormal blood thyroid hormone levels usually take 4–8 weeks to normalize. Till the correct replacement dose of thyroid hormone is established, thyroid function tests must be done once in 4–8 weeks. Thereafter, they may be done at least once in 6 months in children and at least once in 8–10 months in adults. In pregnancy, they may be checked at least once in 2–3 months.

Hypothyroid patients who are properly treated can enjoy a normal sex life. In particular, hypothyroid women who are properly treated can have regular menstrual cycles, normal conception, pregnancy and delivery. There is no excess risk of congenital defects in the new born. The off springs of hypothyroid individuals need not necessarily have thyroid disorders.