Graves

Graves Disease

Definition of Disease

Graves disease is an autoimmune disorder that leads to over activity of the thyroid gland (hyperthyroidism). Graves disease is the leading cause of hyperthyroidism.

Detailed pathophysiology at cellular, tissue, organ, and system levels

Graves disease is a form of type II hypersensitivity where the immune system makes antibodies called thyroid-stimulating immunoglobin (TSI) that attach to thyroid cells and mimic the actions of thyroid stimulating hormone and stimulate the thyroid to make too much thyroid hormone. The TSI stimulation of TSH receptors in the gland result in hyperplasia or goiter and also increased synthesis of thyroid hormone and especially triiodothyronine (T3). An overabundance of thyroid hormones affect all of the physiologic system such as metabolism, heart function, nervous system, body temperature and more. The two main manifestations of Graves disease are opthalmopathy and pretibial myxedema. Opthalmopathy results from hyperactivity of the autonomic nervous system which causes a lag of the globe or lid of the eye causing either an upward or downward gaze. Exophthalmos is caused by infiltrative changes caused by TSH receptor autoantibodies reacting with orbital fibroblast receptors which causes inflammation and edema of orbital contents. Individuals may also experience double vision caused by weakness to the extraocular muscles. Pretibial myxedema is subcutaneous swelling on the anterior portions of the legs and are indurated and erythematous skin. It is caused by thyrotropin receptor antigens on fibroblasts and recruited T lymphocyte that stimulate excess amounts of hyaluronic acid production in the dermis and subcutis,

Genetics

Exact cause of Graves disease is not known however genetic factors interacting with environmental factors play a role in the pathogenesis of this disease.

Epidemiology

Graves disease is most common in women under 40 years old. People with a family history of Graves disease or history of other autoimmune diseases have a higher risk of developing Graves disease.

Disease Described

People with Graves disease will likely present with some or all of the following symptoms. Exophthalmos and pretibial myxedema are significant for Graves disease. The patient would also likely have decreased TSH and elevated T3 and T4 levels. Patients may also present with a goiter and a bruit may be able to be heard over the goiter.

Sign and Symptoms

• Exophthalmos
• Myxedema
• Nervousness or irritability
• Fatigue
• Muscle weakness
• Heat intolerance
• Rapid/Irregular heartbeat
• Hand tremors
• Weight loss
• Goiter

Diagnosis

Diagnosis is based on physical exam and history looking for above signs and symptoms. Lab tests that would be ordered would be TSH, T3, T4, radioactive iodine uptake test, TSI test. Diagnostic tests would also include a thyroid scan.

Treatment

Treatment is aimed at controlling the overactive thyroid. Treatment options are radioiodine therapy, antithyroid medication such as Tapazole, or surgery as a final option.

Links

National Center for Biochemical informations [1] American Thyroid Assocaitation [2] National Institute of Diabetes and Digestive and Kidney Diseases [3] Graves’ Disease and Thyroid Foundation [4]

Related current articles

• National Clearinghouse Guidelines. (2011). Hyperthyroidism and other causes of thyrotoxicosis:

Management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Retrieved from http://www.guideline.gov/content.aspx?id=36623&search=grave%27s+disease

• Chiasera, J. M. (2013). Back to the basics: Thyroid gland structure, function and pathology. Clinical

Laboratory Science, 26(2). 112-117

References

<American Thyroid Association. (2012). Graves’ disease. Retrieved from http://www.thyroid.org/what-is-graves-disease/> <Chiasera, J. M. (2013). Back to the basics: Thyroid gland structure, function and pathology. Clinical Laboratory Science, 26(2). 112-117> <Graves’ Disease and Thyroid Foundation. (2014). About Graves’ disease. Retrieved from http://www.gdatf.org/about/about-graves-disease/> <McCance, K. L., & Huether, S. E. (2014). Pathophysiology: The biologic basis for disease in adults and children (pp. 726-728). St. Louis, MO: Elsevier Mosby> <National Center for Biotechnical Information. (2013). Graves’ disease. Retrieved from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001398/> <National Clearinghouse Guidelines. (2011). Hyperthyroidism and other causes of thyrotoxicosis: Management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Retrieved from http://www.guideline.gov/content.aspx?id=36623&search=grave%27s+disease>