The difference between hypothyroidism and hyperthyroidism

The thyroid, a tiny, butterfly-shaped gland located at the base of the front of your neck, has an enormous impact on your overall health. It affects the function of every organ in your body, and if it is not working properly, it can cause your body to be out of sync.

Sabrina Rene, M.D., an endocrinologist, says your thyroid plays a role in most bodily functions and regulates metabolism and body temperature.

“When your thyroid is not working properly, it can lead to a whole host of symptoms,” she says. “While these symptoms may present themselves slowly and inconspicuously, it is always important to listen to your body, track changes and talk to your doctor if you have any concern at all.”

Hypothyroidism symptoms and treatment

Hypothyroidism occurs when the gland is underactive. This can present itself at any age, but the risk increases as you get older, and it is most commonly triggered by genetics. Women are three times more likely than men to develop hypothyroidism.

“When you have an underactive thyroid, your immune system is triggered to fight your thyroid, causing inflammation, which causes your thyroid to produce fewer thyroid hormones.” Dr. Rene says. “The symptoms are typically vague and often resemble those that occur in other disorders, like iron deficiency. Therefore, it can be often confused with other conditions that cause fatigue.”

However, she says hypothyroidism is easy to test for with a simple screening called a thyroid-stimulating hormone (TSH) test.

Common causes of hypothyroidism include:

• Hashimoto’s thyroiditis, an autoimmune disorder

• Genetics

• Low-iodine diet

• Radiation exposure from cancer treatment

• Certain medications used to treat cancer, heart problems and psychiatric conditions

• Surgical removal of the thyroid

Symptoms of hypothyroidism

• Unexplained weight gain or trouble losing weight

• Fatigue

• Depression

• Hair loss and dry hair

• Muscle cramps

• Dry skin

• Goiter (swelling of the thyroid gland)

• Brittle nails

• Slow heart rate

• Irregular period

• Sensitivity to cold

• Constipation

• Carpal tunnel syndrome

Treatment for hypothyroidism

Levothyroxine sodium tablets (aka Synthroid) can be taken once a day as a replacement hormone to help regulate thyroid levels. These tablets contain a synthetic hormone identical to thyroxine, the hormone that the thyroid gland produces naturally.

Dr. Rene explains that, generally, thyroid replacement medication must be taken for life because the effects of hypothyroidism are irreversible. 

Hyperthyroidism symptoms and treatment

Hyperthyroidism is basically the opposite of hypothyroidism. It occurs when the thyroid is overactive, producing too much thyroid hormone.

Common causes of hyperthyroidism include:

• Graves' disease, a common autoimmune condition that stimulates the thyroid hormones T4 and T3

• Swollen thyroid

• Thyroid nodules

Symptoms of hyperthyroidism

• Unexplained weight loss

• Feeling wired or anxious

• Racing heartbeat

• Shakiness

• Sweating spells

• Feeling hot, frequently

• Itchy red skin

• More frequent bowel movements than usual

• Fine hair and hair loss

Treatment for hyperthyroidism

Methimazole or Propylthiouracil (PTU) is used to treat hyperthyroidism. They signal the thyroid to slow down T4 and T3 hormone production. The medication comes in a tablet and may be taken up to three times daily. Again, this is not a cure.

If anti-thyroid medications don’t control the condition, surgery or radioactive iodine may be used to slow thyroid hormone production.

“If left untreated, hyperthyroidism can lead to an irregular heart rhythm and excessive bone loss,” Dr. Rene says. “Most people respond well once hyperthyroidism is diagnosed and treated, but it is important to seek immediate medical care if you feel any of the hyperthyroid symptoms. This is especially true if you have an irregular heart rhythm, which can lead to a life-threatening condition such as stroke.”

It is beneficial to know your family history because hypothyroidism is often a genetic condition. In addition, Dr. Rene suggests women of childbearing age notify their gynecologist/obstetrician of either of these conditions because they can affect the baby during pregnancy.

If any of these symptoms sound familiar, talk to your doctor. Early intervention makes treatment more successful. Left untreated, prolonged periods of high or low thyroid function can cause significant health problems.

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