What causes hyperthyroidism?
Although there are many causes of hyperthyroidism, three or four diseases account for the majority of cases. The most common by far is Graves' disease.
Graves' disease takes its name from the physician who first described the condition. In some countries the disease may be called Basedow's or Parry's disease. Graves' disease is thought to be caused by a disordered immune system that attacks the thyroid and causes it to become over-active. It is an example of an "autoimmune disorder" where the immune system gets "confused" and accidentally attacks one of our organs instead of doing its usual job of fighting off bacteria and viruses that cause infections.
Other common causes of hyperthyroidism include:
- Graves' disease
- silent thyroiditis
- subacute thyroiditis
- post-partum thyroiditis
- toxic nodule
- toxic multinodular gland
- pituitary tumor
- ovarian or testicular tumor
- excessive ingestion of thyroid hormone (either in the form of thyroid supplements or thyroid tissue from animals)
Is hyperthyroidism hereditary?
If a close relative has either an over-active or an under-active thyroid, then you are at increased risk to develop thyroid disease. Often, one relative will have an over-active thyroid and the next will have an under-active thyroid.
Signs and symptoms of hyperthyroidism
The symptoms of an over-active thyroid can develop slowly and be missed or confused with other illnesses. If you think you have some of the symptoms listed here, see your physician. Excess thyroid hormone will speed up your metabolism - in many ways it is like the body is stuck in "overdrive". The heart rate increases, muscles can become weak and hands can begin to shake with a tremor. Bowel movements can be more frequent and many people feel a sense of agitation or anxiety. Warm rooms can become intolerable and sweating may occur with minimal or even no exertion. Shortness of breath may occur. Roommates may notice that people with hyperthyroidism keep turning down the heat when others find it too cold. The increase in metabolism often causes a significant weight loss that can be very rapid. Some people with overactive thyroids can lose 20 or more pounds in as little as a month. Eyes may become prominent or bulging. Osteoporosis may occur. Women may find their menstrual periods become irregular or even stop completely. Breast enlargement may occur in men.
How is an over-active thyroid diagnosed?
Thyroid function can be measured easily with a simple blood test. Usually this means measuring a thyroid stimulating hormone level (TSH). When the TSH level is low the thyroid is generally over-active. Sometimes additional tests such as a T4 or a T3 blood level need to be done. Once an over-active thyroid has been identified, a radioactive iodine thyroid scan can be helpful to clarify the cause of the hyperthyroidism.
Dr. Richard Bebb, MD
in association with the MediResource Clinical Team
All material copyright MediResource Inc. 1996 – 2018. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: www.medbroadcast.com/healthfeature/gethealthfeature/Thyroid-Disease-Hyperthyroidism-and-Hypothyroidism