Hyperthyroidism: Overview, Causes, and Symptoms

Woman looking uncomfortable as she holds her hand against her neck under the thyroid gland

In recognition of National Thyroid Awareness Month, we are providing information each week about the thyroid: roles, dysfunction, symptoms and treatments. This week, our focus is on one of the most common thyroid dysfunctions - Hyperthyroidism.

As we discussed last week, the thyroid is a butterfly shaped gland in the neck that produces hormones which are released into the bloodstream to control the body's growth. Thyroid hormones play a significant role in the pace of many processes in the body, collectively known as metabolism. Hyperthyroidism, or overactive thyroid, happens when the thyroid gland produces too much hormone. It is distinctly different from hypothyroidism, or an underactive thyroid. "Hyper" means there is too much thyroid hormone in the system, and "hypo" means there is too little. If there is too much thyroid hormone, every function of the body tends to speed up, resulting in impacts throughout the body.

Approximately 1.2% of people in the United States have an overactive thyroid. Hyperthyroidism typically affects more females than males and most commonly occurs in people over the age of 60. There are numerous causes of hyperthyroidism and a wide range of possible symptoms. It usually begins slowly, but in younger people, the onset of symptoms can be sudden.

People with mild hyperthyroidism may have no symptoms and are often unaware that they have it. If/when symptoms arise, they can affect the whole body and many body functions. Most symptoms are related to the increase in metabolism and can include:

  • The development of a goiter, which is swelling in the neck caused by an enlarged thyroid gland
  • Nervousness, irritability, mood swings, and reduced concentration
  • Diarrhea
  • Difficulty breathing
  • Fatigue and difficulty sleeping
  • Muscle weakness
  • Hyperactivity
  • Oversensitivity to heat, excessive sweating, and warm, damp skin
  • Increased appetite
  • Increased bowel movements and urination
  • Infertility and a loss of interest in sex
  • Itchy skin with raised, itchy swellings, often called hives
  • Nails becoming loose
  • Menstrual problems, especially lighter periods or absence of periods
  • Alopecia or patchy hair loss
  • A faster heartbeat, sometimes with palpitations
  • Redness on the palms of hands
  • Sudden weight loss or gain
  • Trembling hands and shakiness

People with diabetes may experience heightened diabetes symptoms, such as fatigue and increased thirst. Those with heart disease have a higher risk of arrhythmia, heart failure, and other cardiovascular problems. Without treatment, hyperthyroidism can have severe complications. Medication can normally control it by reducing thyroid hormone production. We will discuss treatment options later this month.

Next week we will explore hypothyroidism, the condition where the thyroid gland is in a sub-optimal state and is not producing enough of the thyroid hormones necessary for the body to function.