Health Care

Thyroid Disease: Hyperthyroidism vs. Hypothyroidism

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Your thyroid creates and produces hormones that play a role in many different systems throughout your body. When your thyroid makes either too much or too little of these hormones, it’s called thyroid disease. There are several different types of thyroid disease, including hyperthyroidism and hypothyroidism.

Thyroid disease impacts about 20 million Americans, but many don’t even know they have it. That’s why we’re here to break down the differences between hyperthyroidism and hypothyroidism, along with signs to look for and potential treatment plans. It’s important to get a diagnosis as early as possible — because thyroid disease affects your whole body.

What is Hyperthyroidism?

Hyperthyroidism occurs when your body makes too much of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). The thyroid becomes overactive as a result. If you have hyperthyroidism, you may experience a fast heartbeat, increased appetite, anxiety, sensitivity to heat or sudden weight loss.

Hyperthyroidism most commonly occurs in three ways: thyroiditis, or inflammation of the thyroid; a thyroid nodule that produces too much T4 hormone; or an autoimmune condition known as Graves’ disease.

Major symptoms of Graves’ disease are puffy eyes, fast heartbeat and swelling of the thyroid gland (goiter). If left untreated, hyperthyroidism can cause bone loss or an irregular heartbeat.

What is Hypothyroidism?

The thyroid gland controls every aspect of your body’s metabolism. In hypothyroidism, the gland’s hormone production slows, which slows your metabolism. This can lead to weight gain. Hypothyroidism is common, affecting about 4.6% of the U.S. population.

Hashimoto’s thyroiditis is the most common cause of hypothyroidism. With this autoimmune condition, your body attacks its own immune system. Over time, this causes the thyroid to stop producing hormones as it should, which leads to hypothyroidism. Hashimoto’s thyroiditis occurs more frequently in women than men.

Differences Between Hyperthyroidism and Hypothyroidism

Hypothyroidism is more common than hyperthyroidism in the U.S. However, it’s not uncommon to have an overactive thyroid and then an underactive thyroid, or vice versa.

Symptoms between the two may present almost like polar opposites. With hyperthyroidism, you may find yourself with more energy and experience weight loss as opposed to weight gain. You may also feel anxious.

Hypothyroidism causes symptoms like slowed metabolism, fatigue and weight gain. Having an underactive thyroid can decrease or slow down your bodily functions. You might experience depression more commonly than anxiety.

Hyperthyroidism Symptoms

  • Anxiousness
  • Fast heart rate
  • Hand tremor
  • Irritability
  • Muscle weakness
  • Trouble sleeping
  • Weaker or less frequent menstrual periods
  • Weight loss

Hypothyroidism Symptoms

  • Cold sensitivity
  • Constipation
  • Dry skin
  • Fatigue
  • Forgetfulness
  • Weight gain

The most common difference between the two diseases relates to hormone levels. Hypothyroidism leads to a decrease in hormones. Hyperthyroidism leads to an increase in hormone production.

Diagnosing Thyroid Disease and Treatment Options

Finding a skilled doctor is an important part of your treatment plan. Your doctor will order a blood test for thyroid-stimulating hormone (TSH, also called serum thyrotropin) that’s used to screen for thyroid problems. Because TSH stimulates production of your thyroid hormones, TSH is high when your body is not making enough thyroid hormone (hypothyroidism) and low when it makes too much (hyperthyroidism).

Medications, radioactive iodine or surgery to remove the gland are treatment options for hyperthyroidism. If left untreated, hyperthyroidism can cause bone loss or an irregular heartbeat.

For hypothyroidism, while there is currently no cure, there are medications that can treat the disease. The goal of the medication is to treat the symptoms, improve your body’s thyroid function, restore hormone levels and allow you to live a more fulfilling, normal life.

With You for the Whole Journey

If you find you’re experiencing unusual symptoms, reach out to your primary care doctor today so he or she can order the right tests to check your thyroid and get you back on track with treatment as quickly as possible. If you should need further evaluation and treatment, you may be referred to an endocrinologist for specialized care. Learn more about our endocrinology program here.

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