Hypothyroidism: What you need to know

The thyroid is a butterfly-shaped gland in the front of your neck. It makes thyroid hormones that are carried by your blood to all the organs in your body. These hormones control the way your body uses energy and help to control many functions in the body.

The body produces two different types of thyroids hormones:

• Triiodothyronine, also known as T3
• Thyroxine, also known as T4

Thyroid hormones help the body use energy, stay warm, and keep the brain, heart, muscles, and other organs working as they should. They control important body functions such as:

• Heart rate
• Body temperature
• Skin and nail growth
• Body weight
• Menstrual cycle
• Brain functions

Hypothyroidism is a condition in which the thyroid gland is not able to make enough thyroid hormones to keep your body running normally. When levels of thyroid hormones are low, the body burns energy slower than normal. This can affect a variety of functions in the body and cause the person’s heart rate to slow down or make them feel cold.

People of any age can get hypothyroidism, but it is more common in older adults. Women age 60 and older have the highest risk of having low thyroid function. You are also more likely to get hypothyroidism if it runs in your family.

Other causes include:

• Surgery that removed or damaged the thyroid gland
• Hypothyroidism can happen in some infants at birth
• Radiation therapy for cancer that damaged the thyroid
• Infections by viruses
• Some medications, such as amiodarone and lithium

The symptoms of hypothyroidism occur slowly. At first, you may not notice them, or you may think that they are part of normal aging. Hypothyroidism can cause many normal functions in the body to start to slow down. This can cause symptoms such as: 

• Feeling tired, weak, or depressed
• Not being able to stand the cold
• Weight gain
• Dry skin and brittle nails
• Memory problems or trouble thinking clearly
• Slow heart rate
• Constipation
• Heavy or irregular menstrual periods

Having a low level of thyroid hormones affects your whole body. If left untreated, hypothyroidism can cause medical problems including:

• Infertility and difficulty having a child
• Weight gain and obesity
• Heart problems, such as a build up of fluid around the heart, and even high cholesterol
• Joint pain and stiffness
• Goiter (an abnormal enlargement of the thyroid)

Hypothyroidism can be treated by replacing the thyroid hormones that your own thyroid cannot make. To do this, your doctor will normally prescribe tablets of thyroid hormones.  These pills will increase your thyroid hormones in the body to the levels needed for normal function. The exact dose of medication depends on your age, weight, level of hypothyroidism, other health problems you have, and other medications you are taking.

The good news is that hypothyroidism can almost always be completely controlled with the use of thyroid hormone pills, taken regularly at the prescribed dose.

People with hypothyroidism will need a specific amount of thyroid medication to help their body function normally. However, too much thyroid hormone medication can also cause problems. Your doctor will have to find the right amount, just for you.

To find the right amount, your doctor will check your blood work. Blood work for hypothyroidism measures the level of thyroid hormones in your blood, and the level of another hormone called ‘thyroid stimulating hormone’ (TSH). As you take your thyroid medication and replenish the level of thyroid hormones in your blood, your TSH levels will come down to the normal range. By checking both of these levels, your doctor can make sure you are taking just the right amount of thyroid medication.

Once you are at a stable dose, your doctor will normally require you to have blood tests once or a few times a year. This will help your doctor monitor your condition and make sure that your getting the most benefit from the thyroid medication.

It is important to see your doctor for regular visits to make sure you have the right dose. Getting too much or too little thyroid hormone can cause problems.