Hypothyroidism

Hypothyroidism refers to any state in which thyroid hormone production is below normal. There are many disorders that result in hypothyroidism. These disorders may directly or indirectly involve the thyroid gland. Because thyroid hormone affects growth, development, and many cellular processes, inadequate thyroid hormone has widespread consequences for the body.

Women, especially those older than 50, are more likely to have hypothyroidism than men are. Hypothyroidism seldom causes symptoms in the early stages, but over time, untreated hypothyroidism can cause a number of health problems, such as obesity, joint pain, infertility and heart disease.

The good news is that accurate thyroid function tests are available to diagnose hypothyroidism, and treatment of hypothyroidism with synthetic thyroid hormone is usually simple and effective once the proper dosage is established.

Signs and Symptoms

The signs and symptoms of hypothyroidism vary widely, depending on the severity of the hormone deficiency. But in general, any problems you do have tend to develop slowly, often over a number of years.
At first, you may barely notice symptoms such as fatigue and sluggishness, or you may simply attribute them to getting older. But as your metabolism continues to slow, you may develop more obvious signs and symptoms, including:

• Increased sensitivity to cold
• Constipation
• Pale, dry skin
• A puffy face
• Hoarse voice
• An elevated blood cholesterol level
• Unexplained weight gain
• Muscle aches, tenderness and stiffness
• Pain, stiffness or swelling in your joints
• Muscle weakness
• Heavier than normal menstrual periods
• Depression

When hypothyroidism isn't treated, signs and symptoms can gradually become more severe. Constant stimulation of your thyroid to release more hormones may lead to an enlarged thyroid (goiter). In addition, you may become more forgetful, your thought processes may slow or you may feel depressed.
Advanced hypothyroidism, known as myxedema, is rare, but when it occurs it can be life-threatening. Signs and symptoms include low blood pressure, decreased breathing, decreased body temperature, unresponsiveness and even coma. In some cases, myxedema can be fatal.

Hypothyroidism in children and teens
Although hypothyroidism most often affects middle-aged and older women, anyone can develop the condition, including infants and teenagers. Initially, babies born without a thyroid gland or with a gland that doesn't work properly may have few signs and symptoms. When newborns do have problems with hypothyroidism, they may include:

• Yellowing of the skin and whites of the eyes (jaundice). In most cases, this occurs when a baby's liver can't metabolize a molecule called bilirubin, which normally forms when the body recycles old or damaged red blood cells.
• Frequent choking.
• A large, protruding tongue.

As the disease progresses, infants are likely to have trouble feeding and may fail to grow and develop normally. They may also have:

• Constipation
• Poor muscle tone
• Excessive sleepiness
• When hypothyroidism in infants isn't treated, even mild cases can lead to severe physical and mental retardation.

In general, children and teens who develop hypothyroidism have the same signs and symptoms as adults do, but they may also experience:

• Poor growth, resulting in short stature
• Delayed development of permanent teeth
• Delayed puberty
• Poor mental development

More about Hypothyroidism

Causes

• Hashimoto's Thyroiditis
• Lymphocytic Thyroiditis After Hyperthyroidism
• Thyroid Destruction (from radioactive iodine or surgery)
• Pituitary or Hypothalamic Disease
• Medications
• Severe Iodine Deficiency

Risk Factors

• Hypothyroidism is more common in older people.
• Women are more likely to be affected than men.
• Autoimmune hypothyroidism is more likely in those who have other conditions resulting from an autoimmune disorder such as type 1 diabetes mellitus, vitiligo and Addison's disease.
• Some medicines can affect the normal functioning of the thyroid gland. These include lithium carbonate (for bipolar disorder) and amiodarone (for heart rhythm abnormalities).
• Have a close relative, such as a parent or grandparent, with an autoimmune disease
• Have been treated with radioactive iodine or anti-thyroid medications
• Received radiation to your neck or upper chest
• Have had thyroid surgery (partial thyroidectomy)
  

Diagnosis

Because hypothyroidism is more prevalent in older women, some doctors recommend that older women be screened for the disorder during routine annual physical examinations. Some doctors also recommend that pregnant women or women thinking about becoming pregnant be tested for hypothyroidism.

In general, your doctor may test for an underactive thyroid if you're feeling increasingly tired or sluggish, have dry skin, constipation and a hoarse voice, or have had previous thyroid problems or goiter.

• Blood tests
  Diagnosis of hypothyroidism is based on your symptoms and the results of blood tests that measure the level of TSH and sometimes the level of the thyroid hormone thyroxine. A low level of thyroxine and high level of TSH indicate an underactive thyroid. That's because your pituitary produces more TSH in an effort to stimulate your thyroid gland into producing more thyroid hormone.
• In the past, doctors weren't able to detect hypothyroidism until symptoms were fairly advanced. But by using the sensitive TSH test, doctors are able to diagnose thyroid disorders much earlier — often before you ever experience symptoms. Because the TSH test is the best screening test, your doctor will likely check TSH first and follow with a thyroid hormone test if needed. TSH tests also play an important role in managing hypothyroidism. They help your doctor determine the right dosage of medication, both initially and over time.
• In addition, TSH tests are used to help diagnose a condition called subclinical hypothyroidism, which usually causes no outward signs or symptoms. In this condition, you have normal blood levels of T-3 and T-4, but higher than normal levels of TSH.
  

Treatment Approach
With the exception of certain conditions, the treatment of hypothyroidism requires life-long therapy. Presently, a pure, synthetic T4 is widely available. Therefore, there is no reason to use desiccated thyroid extract.
As mentioned earlier, the most active thyroid hormone is actually T3. So why do physicians choose to treat patients with the T4 form of thyroid T3 is available and there are certain indications for its use. However, for the majority of patients, a form of T4 is the preferred treatment. This is a more stable form of thyroid hormone and requires once a day dosing, whereas T3 is much shorter-acting and needs to be taken multiple times a day. In the overwhelming majority of patients, synthetic T4 is readily and steadily converted to T3 naturally in the bloodstream, and this conversion is appropriately regulated by the body's tissues. Pregnancy
The functioning of the thyroid gland can change during pregnancy. In the first half of pregnancy it is normal for the total amount of thyroid hormone to be slightly increased.
Women with hypothyroidism need more frequent checks during pregnancy, as their thyroxine requirements tend to increase.Medications

Hypothyroidism Medications

• Synthroid