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Hyperthyroidism (overactive thyroid)

Hyperthyroidism (overactive thyroid) occurs when your thyroid gland releases more hormones to your body than you need. The thyroid creates two main hormones, triiodothyronine (T3) and thyroxine (T4). The extra hormones your body creates speeds up your metabolism, which can affect the entire body such as unintentional weight loss and raid or irregular heartbeat.

Signs & Symptoms

There are many symptoms to hyperthyroidism that can impact your entire body; sometimes it can be difficult to diagnosis. You may experience some of these symptoms or many of them simultaneously. Symptoms of hyperthyroidism include:

  • Weight loss
  • Irregular heartbeat (arrhythmia)
  • Rapid heartbeat (palpitations)
  • Increased appetite
  • Nervousness, anxiety and irritability
  • Tremor — usually a fine trembling in your hands and fingers
  • Intolerance to heat and excessive sweating
  • Changes in menstrual patterns
  • Changes in bowel patterns, especially more frequent bowel movements
  • Swelling and enlargement of the neck from an enlarged thyroid gland
  • Fatigue, muscle weakness
  • Difficulty sleeping
  • Thin skin
  • Hair loss and brittle hair


Your healthcare provider may perform the following diagnoses:

  • Review your medical history
  • Physical exam: Your doctor will perform a physical exam of your neck to check the size of your thyroid gland and if it’s bumpy or tender. Your fingers, eyes, heart and skin will also be examined.
  • Imaging tests: Allows for the doctor to get a better idea on the size and shape of the thyroid.
  • Blood tests: Blood samples will be taken to measure for high levels of thyroid hormone, this is called thyroid function testing. When you have hyperthyroidism, levels of thyroid hormones T3/T4 are above normal and thyroid stimulating hormone is lower than normal.