Thyroid Disorders
Hypothyroidism an Overview
| Types & Causes |
| Diagnosis & Detection |
| Management |
Introduction
What is Hypothyroidism ?
When the thyroid gland produces less hormone than what is required by the body the person is said to be suffering from hypothyroidism.
The thyroid is a small butterfly shaped gland located in the 'throat' region, in front of the windpipe. The function of the thyroid gland is to make, store and release thyroid hormones. The hormones produced by the thyroid gland influence almost all the organs, every tissue and every cell in the body.
Thyroid hormones regulate the body's metabolism too. They have a bearing on the heart rate, cholesterol level, body weight, energy level, muscle strength, skin condition, menstrual regularity, memory function and many other conditions.
If the thyroid gland becomes over active and produces more hormones than are needed by the body the condition is called hyperthroidism. But, the most common thyroid disorder results from an underactive thyroid gland, or hypothyroidism. This results when the thyroid fails to produce enough hormones.
The influence of the thyroid gland is both far-reaching and critical to normal body function. Hypotheriodism was first discovered as recently as in early 19th century when physicians surgically removed the thyroid gland and observed some of the same symptoms as in hypothyroidism. They named this syndrome - Myxoedema. Despite its pervasive influence, however, the thyroid gland and its disorders are still not widely understood among the general public.
To simplify the situation for easier understanding: First, the hypothalamus sends a signal to the pituitary gland which in turn releases its own hormone to activate the thyroid gland. On receiving the signal from the pituitary gland, the thyroid releases its own two hormones T3 and T4.
Hypothyroidism may also result when the immune system produces antibodies that destroy the thyroid tissue. As the damaged thyroid gland produces less thyroid hormones, the pituitary gland secretes more thyroid-stimulating hormone (TSH) to encourage the thyroid gland to work harder. This increased demand on the thyroid may cause it to enlarge, resulting in what is commonly known as a goitre.
High Risk Categories
There are a lot of people who seem to be more prone to becoming hypothyroid than others. Various factors may be involved in increasing their risk levels.
For example:
- Women, especially those over 40
- Women within 6 months after delivery
- People with past record of thyroid disorder
- People with high cholesterol
- People experiencing depression
- People with a family history of autoimmune thyroid disease
- People who have had x-ray therapy of the head or neck for cancers or Hodgkin's disease
- People who have taken or who are taking lithium or amiodarone
- People with non thyroid autoimmune disease, for example: Addison's disease, Type I diabetes, Pernicious anaemia, Rheumatoid arthritis, Systemic lupus erythematosus, vitiligo
Effect On Daily Life
A common sign of hypothyroidism is a lack of energy or feeling of tiredness. Unfortunately, many people attribute their fatigue solely to lifestyle pressures and demands without thinking that there might be a medical reason for it. Other symptoms of hypothyroidism include mood changes, depression, muscle weakness, unexplained weight gain or loss, and persistent hoarseness.
Complications Due To Neglect
Left untreated, a thyroid disorder can compromise overall health. When the thyroid is not working properly, it can lead to a variety of long-term complications. Although not all of complications will occur in every hypothyroid patient.
Thyroid disorders can affect a patient's
Cardiovascular system:
Slowed heart rate, increased diastolic blood pressure
Central Nervous System:
Decreased concentration, loss of interest and/or pleasure, depression
Gastrointestinal Tract:
Decreased secretion of digestive juices, constipation
Musculoskeletal System:
Muscle stiffness, cramps, weakness, pain, slow muscle stretch reflexes, muscle enlargement, atrophy, joint pain and stiffness
Kidneys:
Fluid retention and edema
Liver:
Increased LDL cholesterol in the blood, elevated triglycerides in the blood
Reproductive System:
Abnormally heavy menstrual bleeding, missed ovulation, decreased fertility, missed menstrual periods
Skin and Hair:
Thickening and dryness of the skin, dry, coarse hair and/or loss of hair, loss of lateral eyebrow hair & other major organs.
Outside of the US, it is iodine deficiency which is one of the most common causes of hypothyroidism. Iodine must be supplied by the diet. It is an essential component of thyroid hormone. Iodine though should be available in normal diet, often it is lacking. A fairly common way to augment iodine requirement of the body is by using iodised salt.
In the US Hashimoto's disease is the most common cause of hypothyroidism. Hashimoto's disease, named after the Japanese doctor who first described it, is an autoimmune condition in which the body's immune system attacks and destroys the thyroid gland.
Signs & Symptoms
In the case of mild thyroid failure, patients often do not show obvious symptoms and thus may not even be aware of their condition. Left untreated, however, mild thyroid failure can progress to where symptoms begin to surface. Some of the more common signs and symptoms of hypothyroidism include:
- Fatigue
- Hoarse voice
- Mood swings
- Difficulty swallowing
- Forgetfulness
- Intolerance to cold
- Dry, coarse skin and hair
Hypothyroidism is often not even suspected. Largely on account of its often vague signs and symptoms, it can be easily confused with other conditions like natural ageing process, menopause or stress. Many patients remain undiagnosed and untreated for years due to their lack of awareness of hypothyroidism and its signs and symptoms.
A trained professional can make a tentative diagnosis of hypothyroidism through investigation of a patient's signs and symptoms. One particular sign that provides strong evidence of a thyroid disorder is a goitre, or enlarged thyroid gland. A patient may describe it as a change in the appearance of the neck, difficulty or discomfort in swallowing, hoarseness, or pain or swelling of the neck.
Thyroid disorders can be detected with a simple blood test. The sensitive Thyroid Stimulating Hormone (TSH) test, considered by most experts to be the front line test for checking thyroid function, is the most valuable single method to discover or confirm hypothyroidism. A simple blood test, the TSH test enables physicians to identify even mild cases of hypothyroidism before symptoms appear.
A high TSH level usually indicates that the thyroid gland is failing to produce enough thyroid hormone. If TSH results come back showing higher than normal levels, you may have hypothyroidism or mild thyroid failure. TSH is a sensitive enough diagnostic tool to even detect sub-clinical hypothyroidism.
A TSH test is administered by drawing a small blood sample and sending it to a laboratory for analysis. The laboratory will read the level of TSH, and based on a reported normal value range, it will determine whether the level is below normal (hyperthyroid), above normal (hypothyroid) or within the normal range (euthyroid).
Fortunately, Hypothyroidism is Very Easily Treated
Hypothyroidism is easily treated with thyroid hormone replacement therapy. Most often the doctor prescribes levothyroxine sodium.
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