Hypothyroidism|Underactive Thyroid.

What is Hypothyroidism. As explained in Thyroid ,when  the thyroid function drops below normal, it is referred to as hypothyroidism. In other words, it is the underactive thyroid which results in hypothyroidism.

As a result of this decreased functioning of the thyroid, the levels of the thyroid hormones T3 and T4 in the blood, fall below normal, and certain symptoms of hypothyroidism  present themselves.

The thyroid  is responsible for the metabolism in the body and due to fall in levels of thyroid hormones, the metabolism is adversely affected.  The more severe form of hypothyroidism is called Myxedema.

Hypothyroid.

Hypothyroid is an underactive thyroid, which does not produce the thyroid hormones to its normal capacity. This results in fall of blood levels of thyroid hormones resulting in hypothyroidism.

Causes of Hypothyroidism.

What causes hypothyroidism. 95% of hypothyroidism cases are caused due to some thyroid diseases. In other words, most of hypothyroidism cases are due to some problems arising in the thyroid itself.  Some of these hypothyroid causes may be reversible while some may be irreversible.

1) Lack of Iodine causes hypothyroidism.

Certain countries typically exhibit a lack of iodine in the diet. As explained in “Thyroid diseases – Basics”, it is with the uptake of iodine from the blood, that the thyroid  is able to make its hormones, T3 and T4. Lack of iodine  prevents the thyroid to make and secrete sufficient hormones and hypothyroidism develops.

2) Hashimoto’s disease causes hypothyroidism.

Hashimoto’s disease (named after Dr Hashimoto, who first described it) is a condition wherein the thyroid gets enlarged and is unable to make sufficient thyroid hormones. This disease or Hashimoto’s thyroiditis is caused by the auto immune system of our body, which attacks the thyroid tissue and destroys it. The cause is unknown, but there is a hereditary trait and it does run in families.

3) Destruction of the thyroid tissue due to treatment after hyperthyroidism.

Treatment of hyperthyroidism with radioactive iodine therapy can result in excessive damage to the thyroid cells resulting in insufficient production of T3 and T4 giving rise to hypothyroidism.

4) Surgical removal of thyroid  for hyperthyroidism.

This will also result in hypothyroidism.

5) Certain medications cause hypothyroidism.

Certain medicines used to treat hyperthyroidism like Tapezole and PTU can cause hypothyroidism. Lithium, used in psychiatry, is also known to disrupt thyroid function.

6) Pituitary gland and hypothalamus damage.

This will result in hypothyroidism. As explained in Thyroid , the thyroid gland function is controlled by the TSH hormone secreted by the  pituitary gland situated in the base of the brain. The pituitary gland is,  in turn, controlled by the TRH hormone situated in the hypothalamus of the brain.

If there is damage to these two, either by a tumor or surgery  or some other pathology, the thyroid function is disturbed and hypothyroidism develops. Hypothyroidism due to pituitary damage is called Secondary hypothyroidism, while hypothyroidism due to hypothalamus damage is called Tertiary hypothyroidism.

Symptoms of Hypothyroidism|Hypothyroid Symptoms.

Patients of hypothyroidism may  present  some or all of the hypothyroidism symptoms mentioned below and these symptoms are not the same for all the patients. But, in short, these hypothyroid symptoms are due the adverse effect that hypothyroidism has on the metabolic activity of the body. Those patients, in whom, the hypothyroidism is mild may not even present any of these symptoms.

Hypothyroidism Symptoms Checklist.

1) Dry skin

2) Dry hair and hair loss.

3) A feeling of depression and irritability.

4) Gain in weight.

5) Fatigue and muscular weakness and pain.

6) Intolerance to cold weather.

7) Hypothyroidism symptoms in women. In addition to symptoms being mentioned here, women may experience abnormal changes in menstrual cycles.

Decreased  libido.

9) Constipation.

10) Difficulty to concentrate.

11) Swelling of legs.

12) Increased levels of cholesterol and triglycerides in blood.

Effects of Hypothyroidism.

If untreated, hypothyroidism causes certain complications which can be serious. Given below are the side effects of hypothyroidism.

• As a result of low levels of thyroid hormones in the blood, the pituitary gland secretes additional Thyroid Stimulating hormone (TSH) in the blood in order to stimulate the thyroid to secrete more T3 and T4, which cannot happen due to the inefficient thyroid in hypothyroidism. This persistent secretion of TSH causes the thyroid to enlarge, resulting in Goitre. (explained in “Non Toxic Thyroid Goitre”.)
• Heart disease
• Infertility
• Miscarriages.

Hypothyroidism Diagnosis.

Once you have been diagnosed with hypothyroidism by your symptoms, your physician will want to confirm the hypothyroidism diagnosis by advising certain blood tests. The tests for hypothyroidism and their results seen in a hypothyroid are explained below.

• Serum cholesterol and Serum triglycerides will be high.
• Blood count will indicate anemia.
• Thyroid hormones, T3 and T4 levels will be below normal. However, in sub clinical hypothyroidism, these levels may be normal. in such a case to confirm the diagnosis of hypothyroidism,  the levels of TSH hormone will have to be determined.
• TSH levels in hypothyroidism. As explained earlier, the pituitary gland secretes the TSH hormone to stimulate the thyroid to secrete its hormones, when their levels in the blood fall. In hypothyroidism, due to decreased function of the thyroid, the pituitary is constantly secreting  the TSH to stimulate the thyroid.  Therefore, in hypothyroidism, TSH levels are raised. This is seen even in sub clinical cases of hypothyroidism. Therefore, increased levels of TSH with even normal levels of T3 and T4 will confirm hypothyroidism.
• However, in cases of secondary hypothyroidism, ( explained above), where the hypothyroidism is due to a defect in the  pituitary gland,  the levels of TSH will be decreased. In such cases, the levels of the hormone secreted by the hypothalamus, the TRH,  is to be determined. Its level will be high as it is secreted in excess to stimulate the pituitary gland to secrete TSH.
• Thyroid scan will help to find out the underlying cause of the thyroid pathology.
• MRI of the brain  is indicated if there is involvement of the pituitary or the hypothalamus.

Treatments for Hypothyroidism.

Thyroid Medication. Treatment of hypothyroidism involves taking thyroid medication throughout life. Frequently the doctor may require monitoring of the thyroid hormones’ blood levels to arrive at the hypothyroid medicine and dosages which best suit that particular hypothyroid patient.

Drugs and medicines for Hypothyroidism.

• Levothyroxine is the drug of choice. Small doses are initially prescribed, to control the symptoms and bring the raised levels of TSH to normal.
• In heart patients, the doses prescribed are even smaller.
• Hormone levels are to be monitored every 2 to 3 months to establish the exact dosage required for you. Once the dosage has been fixed, the monitoring of levels has to be carried out every year.
• Medication is to be taken life long.
• This medicine works best on an empty stomach, and has to be taken in the morning about 60 minutes before breakfast or any other medicine.
• Do not change the brand. If you do so, inform your physician..
• If you develop any symptoms of hyperthyroidism, ( explained in “hyperthyroidism”) consult your physician, who may then have to reduce the dosage.
• Patients of Myxedema can go into coma and require hospitalization and intra venous thyroid hormones and steroids.

Hypothyroid Diet.

There is no such thing as a diet for hypothyroidism. Though claims are made to the contrary, there are no foods that improve the function of the thyroid. However there are certain foods and medicines that can impair the absorption of thyroid medication and thyroid hormones taken for hypothyroidism. Such foods and medications should be avoided. They are:

• Foods containing high dietary fiber.
• Iron and multivitamin tonics.
• Calcium supplements.
• Ulcer medicines such as antacids and sucralfate.
• Certain medicines taken to lower cholesterol such as cholestyramine and colestipol.
• Cottonseed meal.
• Soybean flour.

Prevention Measures for thyroid diseases are not yet established.

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