Graves disease is the most common cause of hyperthyroidism, or increased activity of the thyroid gland. It tends to affect women much more than men and has many clinical manifestations. It is characterized by the production of antibodies that stimulate the thyroid gland to release increasing amounts of thyroid hormone, which causes many of the symptoms.
Cardiovascular Symptoms
Cardiovascular symptoms include increased heart rate, increased blood pressure and palpitations. These signs of increased cardiac activity are a direct result of increased levels of thyroid hormone that stimulate the body's adrenergic system. The adrenergic system, normally powered by stress hormones such as adrenaline, puts the body in a "fight-or-flight" mode.
Goiter
An enlarged thyroid gland, also known as a goiter, is one of the major signs of Graves disease. Due to increased thyroid activity, the cells become larger--in much the same way the mass of a bodybuilder's arms increases with arm exercise in the gym. The enlargement is usually symmetric and diffuse.
Protruding Eyes
Protruding eyes, also referred to as ophthalmopathy, is a symptom unique to Graves disease. As a result of the increased antibody and thyroid activity, cells known as T-cells infiltrate spaces in the tissues around the eye and result in inflammation and swelling. These changes cause the eye to push forward and appear to extend outward.
Skin and Hair Changes
Changes in the skin, especially on the lower limbs, are also known as pretibial myxedema. Similar to what happens in the eye, inflammation and swelling occur, resulting in scaly thickening and discoloration of skin, especially over the shins. Changes in hair, such as general hair loss and thinning, occur due to increased levels of thyroid hormone and are reversible in most cases with treatment.
Lid Lag
In "lid lag," the activity of the eyelid (blinking) is noticeably out of sync with movement of the eye. This again results from increased thyroid hormone levels and is usually not noticed by the patient; typically it's family and friends who bring this symptom to the patient's attention.
Mental Changes
The increased thyroid hormone levels can overstimulate the mind as well as the body. Patients often report increased anxiety, irritability and nervousness and decreased amounts of sleep.
Metabolic Changes
Thyroid hormone can alter metabolism, resulting in significant weight loss. Muscles such as those in the digestive system also tend to work faster, which can lead to diarrhea. Skeletal muscles also tend to be "excited," which can cause excess sweating and tremor, often in the extremities.
References
- "Robbins and Cotran Pathologic Basis of Disease, 8th Edition;" Kumar; 2009
- "Rosen's Emergency Medicine, 7th Edition;" Marx; 2009
- Journal of Clinical Endocrinology and Metabolism; "Hormones and You: Graves' Disease;" R. Bahn et al.; November 2007
