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Division of Oncology
 

Hyperthyroidism (Thyrotoxicosis)

In this condition, the thyroid functions excessively. Symptoms include:

  • inability to tolerate heat
  • increased thirst
  • sweating
  • diarrhea
  • weight loss
  • women may stop having menstrual cycles or have decreased fertility
  • heart symptoms may include a rapid heart rate, atrial fibrillation, or heart failure
  • agitation, emotional instability or tremor

Cause

The most common cause of hyperthyroidism is Graves Disease. This condition is also known as diffuse toxic goiter and is an autoimmune disorder. It is more common in women than in men. Graves Disease presents most commonly in patients from 20 to 40 years old. Patients may have the triad of goiter, exopthalmus (bulging of the eyes) and hyperthyroidism. Laboratory data will show very low thyroid stimulating hormone (TSH) levels with an increased thyroxine hormone (T4) level and autoantibodies.

Treatment

Antithyroid Drugs
Propylthiouracil (PTU) and methimazole (Tapazole) are most commonly used to treat hyperthyroidism. Side effects are rare but may include rash, fever, neuritis, and disorders in the production of red and white blood cells. There is generally an improvement of symptoms within two weeks. The recurrence rate is approximately 30 percent after the medications are discontinued.

Radioacitive Iodine
This treatment is not recommended if the patient is pregnant or breast feeding, and the patient should not get pregnant for 12 months after the treatment. Most patients treated with radioactive iodine have normal thyroid hormone levels within two months, yet only 50 percent still have normal levels six months after treatment. Occasionally, patients may require further treatment. The most common complication is hypothyroidism, which may be treated with oral thyroid hormone supplementation. Other, much less common, complications include hyperthyroidism, worsening in bulging of the eyes, and hyperparathyroidism.

Surgical Treatment
The patient’s thyroid hormone levels should be normal immediately following the operation. [What does the surgery consist of?] Complications include injury to the nerves that control the vocal cords, which causes hoarseness, and injury to the parathyroid glands, which leads to low calcium levels. The risk of either of these complications is 1 percent.