Hypothyroidism – Causes and Treatment

Hypothyroidism is a common endocrine disorder resulting from deficiency of thyroid hormone. It usually is a primary process in which the thyroid gland produces insufficient amounts of thyroid hormone. It can also be secondary, that is lack of thyroid hormone secretion due to the failure of either adequate thyrotropin (ie, thyroid-stimulating hormone [TSH]) secretion from the pituitary gland or thyrotropin-releasing hormone (TRH) from the hypothalamus (secondary or tertiary hypothyroidism).

Symptoms of Hypothyroidism

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.

The symptoms of hypothyroidism are often subtle. They are not specific (which means they can mimic the symptoms of many other conditions) and are often attributed to aging. Patients with mild hypothyroidism may have no signs or symptoms. The symptoms generally become more obvious as the condition worsens and the majority of these complaints are related to a metabolic slowing of the body.

Hypothyroidism Causes

Many permanent or temporary conditions can reduce thyroid hormone secretion and cause hypothyroidism. About 95% of hypothyroidism cases occur from problems that originate in the thyroid gland. In such cases, the disorder is called primary hypothyroidism. (Secondary hypothyroidism is caused by disorders of the pituitary gland. Tertiary hypothyroidism is caused by disorders of the hypothalamus.)

Thyroid surgery. Part or all of the thyroid gland may be removed to treat disorders such as having too much thyroid hormone (hyperthyroidism), an enlarged thyroid gland (goiter) that makes swallowing difficult, thyroid cancer, or thyroid nodules that may be overactive or cancerous. Hypothyroidism results when the thyroid gland is removed or when remaining thyroid tissue does not function properly.

Your thyroid is a small, butterfly-shaped gland located at the base of the front of your neck, just below your Adam's apple. Hormones produced by the thyroid gland have an enormous impact on your health, affecting all aspects of your metabolism.

Hashimoto's disease occurs when the immune or protective mechanisms of the body mistakenly attack the thyroid gland. When the immune system attacks the thyroid gland, it damages part of the gland in such a way that it can no longer produce thyroid hormone.

Diagnostic testing

To diagnose primary hypothyroidism, many doctors simply measure the amount of Thyroid-stimulating hormone (TSH) being produced by the pituitary gland. High levels of TSH indicate that the thyroid is not producing sufficient levels of Thyroid hormone (mainly as thyroxine (T4) and smaller amounts of triiodothyronine (T3)). However, measuring just TSH fails to diagnose secondary and tertiary forms of hypothyroidism, thus leading to the following suggested blood testing if the TSH is normal and hypothyroidism is still suspected:

Hypothyroidism Treatment

The purpose of treatment is to replace the deficient thyroid hormone. Levothyroxine is the most commonly used medication. The lowest dose effective in relieving symptoms and normalizing the TSH is used. Life-long therapy is needed. Medication must be continued even when symptoms subside. Thyroid hormone levels should be monitored yearly after a stable dose of medication is determined.

Doctors usually prescribe thyroid hormone pills to treat hypothyroidism. Most people start to feel better within a week or two. Your symptoms will probably go away within a few months. But you will likely need to keep taking the pills for the rest of your life.

It's important to take your medicine just the way your doctor tells you to. You will also need to see your doctor for follow-up visits to make sure you have the right dose. Getting too much or too little thyroid hormone can cause problems.