Low Energy May Be Due To Underactive Thyroid

Posted on Wed., January 20, 2010
By Dr. Oliver Graham

SUPPOSE YOU have previously been very active, but over the prior few months have become increasingly sluggish, constipated and depressed. What might be the cause?

In fact, there could be many possible causes, including depression, side effects of medicine, and a number of diseases. One such disease is an underactive thyroid, otherwise known as hypothyroidism. A blood test can confirm the diagnosis.

The cause of hypothyroidism is usually that the immune system mistakenly attacks the thyroid gland, which is located on the front of the neck, just below both sides of the Adam's apple. Eventually, the attack leads to a loss of healthy thyroid cells causing a drop in the production of thyroid hormones.

This is called Hashimoto's thyroiditis, named after a Japanese doctor who first described the illness.

The thyroid is like the accelerator of a car. When it's underperforming (hypothyroidism), everything in the body slows down, and patients can develop constipation, weight gain, puffy eyes and intolerance to cold temperatures.

When it's overactive (hyperthyroidism), the body speeds up, and a person can develop weight loss, anxiety, rapid heart rate and intolerance to warm temperatures.

Hypothyroidism can affect many parts of the body, and treatment can often lead to normalization of these conditions. These are some ways that an underactive thyroid can affect the body:

High cholesterol and heart disease: Hypothyroidism slows your body's metabolism and can cause a buildup of bad cholesterol. It can also slow the heart and lead to an enlarged heart or heart failure.
Anemia: People with an under active thyroid can become anemic due to the lack of development of red blood cells. Significant anemia can lead to shortness of breath and fatigue.
Infertility: Many women who suffer from an underactive thyroid also have difficulty conceiving. The odds of becoming pregnant increase significantly after thyroid hormone treatment has begun. Doses of thyroid hormone may need to change during and after pregnancy, so it's important to speak with a doctor.
Myxedema: This is an uncommon, but serious condition which results from long-term and severe low levels of thyroid hormone. Symptoms include severe fatigue, confusion and loss of consciousness.

The good news is that treatment for hypothyroidism is easy. A thyroid hormone pill, called levothyroxine, taken once per day replaces the hormones that are not being produced naturally.

Bad reactions to the medicine are rare. Therapy is usually for life.

Important things to remember while taking thyroid hormone replacements:

It can take four-to-six weeks for a change in levothyroxine dosage to affect your blood level of thyroid hormone. So your doctor will often wait four-to-six weeks after a change in levothyroxine dose before checking your blood level again.
Medicines such as calcium and iron, and for stomach acid, can affect the absorption of thyroid hormone replacements. If you start one of these medications, talk to your doctor.
Tell your doctor if you experience symptoms of hyperthyroidism—restlessness, rapid weight loss or sweating. The dose of levothyroxine may be too high.
If symptoms of hypothyroidism do not go away after a couple of weeks, the dosage may be inadequate or the symptoms may not be the result of a lack of thyroid hormones.

Graham practices internal medicine at Contra Costa Regional Medical Center in Martinez.