Hyperthyroidism is a condition in which the thyroid gland produces too much thyroid hormone. Thyroid hormones influence a wide variety of functions in the body, including cardiac, nerve, gastrointestinal, and mental function.
The majority of cases are caused by Graves' disease, an autoimmune disease that damages the thyroid gland, causing it to overproduce thyroid hormone. Other causes of hyperthyroidism include tumors of the thyroid or pituitary glands, inflammation of the thyroid gland, or excessive ingestion of thyroid hormone pills. The disorder may also be associated with other autoimmune diseases, including Addison's disease and type 1 diabetes mellitus.
The most severe form of hyperthyroidism is thyroid storm, which can be caused by thyroid surgery, acute stress (e.g., infection, trauma, or nonthyroid surgery), or an overdose of iodine in a patient with existing hyperthyroidism. This condition may have symptoms of extreme fever (up to 104 F to106 F), severe nausea, vomiting, jaundice (yellowish discoloration of the skin), agitation, or delirium, and may ultimately lead to seizures and coma.
Symptoms
- Fast heart rate
- Palpitations
- Heat intolerance
- Weight loss
- Menstrual irregularities
- Nausea and vomiting
- Restlessness
- Anxiety
- Tremor
Further signs and symptoms depend on the cause and severity of hyperthyroidism. For example, in Graves' disease, typical symptoms are a goiter (an abnormal lump in the neck), drooping eyelids, and thickening and redness of the skin of the legs.
Risk Factors
Hyperthyroidism is more common in females. Also, individuals with certain genes have an increased risk for Graves' disease.
Hyperthyroidism: Diagnosis and Treatment
Diagnosis
- The evaluation begins with a medical history and a physical examination.
- Blood testing to measure the blood levels of thyroid hormones will diagnose the condition.
- Once hyperthyroidism has been diagnosed, further testing can determine the underlying cause. This may include further blood tests, thyroid scans, or ultrasound.
Treatment
- Initial drug therapy often uses a beta-blocker to decrease symptoms of the disease. Additional drugs that are commonly used include propylthiouracil or methimazole, which decrease thyroid hormone production.
- The definitive therapy is radioactive iodine to destroy part of the overactive thyroid. This is the most commonly used treatment and has excellent success rates. However, it cannot be used during pregnancy.
- Surgical removal of the thyroid (thyroidectomy) is also an effective treatment. It is often recommended in hyperthyroid patients who have a large goiter.
- Lifelong thyroid hormone supplementation will be necessary after these treatments.
- Treatment of thyroid storm is generally similar to that for hyperthyroidism, but with closer monitoring and higher medication doses. Patients should be hospitalized, usually in an intensive care unit.
Hyperthyroidism: Nutritional Considerations
The links between nutrition and hyperthyroidism are limited. The relevant issues are as follows:
- Celiac disease: Individuals with celiac disease have an increased risk of hyperthyroidism. Some evidence indicates that hyperthyroidism can be improved by following a gluten-free diet.
- Iodine ingestion: People diagnosed with hyperthyroidism should attempt a trial period of avoiding foods that contain high concentrations of iodine, including iodized salt, sea salt, seafood, dairy products, eggs, and foods that contain iodides, iodate, algin, alginates, carrageen, agar, and red dye number 3.
