Hypothyroidism

The thyroid produces hormones that influence the body’s metabolism. Hypothyroidism occurs when the thyroid gland is underactive and does not make enough thyroid hormone.

Symptoms of hypothyroidism may include constipation, cold intolerance, fatigue or weakness, paleness or dry skin, depression, weight gain, and thin, brittle hair or fingernails, among others.

The most common cause of hypothyroidism is thyroiditis, which is swelling and inflammation of the thyroid gland. Thyroiditis may be caused by the immune system attacking the thyroid gland, viral infections such as the common cold, or pregnancy which is called postpartum thyroiditis. Other causes of hypothyroidism include certain medicines, such as lithium and amiodarone, congenital hypothyroidism, radiation treatments to the neck or brain, radioactive iodine used to treat an overactive thyroid gland, or surgical removal of part or all of the thyroid gland among others.

The goal for treatment is replacing the thyroid hormone as well as obtaining and keeping TSH in the normal range. Levothyroxine is the most commonly used medicine, a synthetic thyroid hormone. 

Symptoms of hypothyroidism may include:

• Hard stools or constipation
• Feeling cold
• Fatigue or weakness
• Heavier and irregular menstrual periods
• Paleness or dry skin
• Sadness or depression
• Thin, brittle hair or fingernails
• Weight gain
• Forgetfulness
• Slower heart rate

The thyroid gland is an important organ of the endocrine system. It is located at the front of the neck, just above where your collarbones meet. The thyroid makes hormones that control the way every cell in the body uses energy. This process is called metabolism.

The most common cause of hypothyroidism is thyroiditis, which is swelling and inflammation of the thyroid gland.

Thyroiditis may be caused by:

• The immune system attacking the thyroid gland
• Viral infections such as the common cold
• Pregnancy which is called postpartum thyroiditis

Hypothyroidism may be caused by:

• Certain medicines, such as lithium and amiodarone
• Congenital hypothyroidism. In this case, babies are born without a thyroid, with a partly formed one, or the thyroid is in the wrong location.
• Radiation treatments to the neck or brain
• Radioactive iodine used to treat an overactive thyroid gland
• Surgical removal of part or all of the thyroid gland
• Sheehan syndrome, which is a condition when a woman bleeds severely during pregnancy or childbirth and causes the destruction of the pituitary gland
• Pituitary tumor or pituitary surgery

Hypothyroidism is more common in women and people over age 50.

Your doctor will perform a physical exam and will examine your thyroid gland. Your doctor will also look for the following signs and symptoms:

• Brittle nails
• Pale or dry skin
• Thin and brittle hair
• Slower heart rate
• Depression
• Constipation

Your doctor will order blood tests which include thyroid-stimulating hormone (TSH) and T4.   

With proper treatment, thyroid hormone levels will likely return to normal. However, you will likely need to take a thyroid hormone medicine for the rest of your life.

When starting your medicine, your doctor may check your hormone levels every 2 to 3 months. After that, your thyroid hormone levels should be monitored at least once every year. Pregnant women or those patients, who take medications that can interact with levothyroxine, may need more frequent monitoring.

When you are taking thyroid medicine, be aware of the following:

• Do not stop taking the medicine even if you feel better.
• It may take several weeks before you notice a change in your symptoms. Continue taking your medication exactly as your doctor prescribed.
• Tell your doctor if you change from brand formulation to generic (levothyroxine) or vice versa. Your doctor may need to check your levels.
• Do not switch brands without talking to your doctor, as each brand of levothyroxine contains a slightly different amount of medication. Your doctor may need to check your levels if you switched.
• To ensure proper absorption, take levothyroxine on an empty stomach and when taken 1 hour before any other medications. Ask your doctor if you should take your medicine at bedtime. Some studies have shown taking levothyroxine at bedtime may allow better absorption  than taking it in the daytime.
• To ensure proper absorption, wait at least 4 hours after taking thyroid hormone before you take fiber supplements, calcium, iron, multivitamins, aluminum hydroxide antacids, and colestipol.

While you are taking thyroid medicine, tell your doctor if you have any symptoms that suggest your dose is too high, such as:

• Palpitations
• Rapid weight loss
• Restlessness or shakiness
• Sweating

The goal for treatment is replacing the thyroid hormone as well as obtaining and keeping TSH in the normal range.

Levothyroxine is the most commonly used medicine. You will likely need to take thyroid hormone medicine for the rest of your life.

There is no cure for hypothyroidism, and most patients will have hypothyroidism for life. You will likely take a thyroid hormone medicine for the rest of your life.

There are some exceptions: many patients with viral thyroiditis as well as patients with thyroiditis after pregnancy have their thyroid function return to normal.

Possible Complications:

Myxedema coma, the most severe form of hypothyroidism, is rare. It occurs when thyroid hormone levels get very low. It can be caused by an infection, illness, exposure to cold, or certain medicines in people with untreated hypothyroidism.

Myxedema coma is a medical emergency and must be treated in the hospital. Tell your doctor if you notice any of the following signs or symptoms:

• Below normal temperature
• Decreased breathing
• Low blood pressure
• Low blood sugar
• Unresponsiveness

People with untreated hypothyroidism are at increased risk of Infertility, miscarriage, or giving birth to a baby with birth defects.