Hyperthyroid Disorders

Lesson 4: Causes of Hyperthyroidism

Graves' Disease

Graves’ disease is an autoimmune condition that's responsible for most instances of hyperthyroidism. The thyrotoxicosis caused by Graves’ disease causes symptoms similar to those that occur in other types of hyperthyroidism. Typically, patients become nervous, irritable, experience weight loss, and develop similar symptoms.

However, Graves’ disease can also cause unique symptoms that are related to its autoimmune nature. These symptoms include congestive eye disease, pretibial myxedema, acropachy, which causes soft tissue swelling in the hands and feet, hives, itching and enlargement of the thymus gland or spleen.

Graves’ disease can affect patients of all ages. In the newborn, a transient form of hyperthyroidism can occur when the mother’s thyroid antibodies pass through the placental membrane to the fetal circulation. This is a passive form of disease in which symptoms occur until the thyroid antibodies, which are proteins, break down and exit the blood circulation. Otherwise, Graves’ disease is rarely seen in children younger than 2 because their immune systems do not fully mature until then.

Graves disease occurs in about seven times as many women as men, and estrogen is suspected of triggering Graves’ disease. Women between ages 30 through 60 are most likely to develop Graves’ disease, and women with a family history of autoimmune disease are at increased risk. Patients who smoke cigarettes, are receiving medications with interferon and interleukin or who have a history of previous high-dose neck irradiation are also at increased risk of developing Graves’ disease.

Elderly patients are more likely to have an atypical apathetic form of hyperthyroidism. These patients usually have cardiac symptoms and weight loss but generally do not have the other typical symptoms of thyrotoxicosis. Elderly Graves’ disease patients are more likely to have atrial fibrillation, systolic hypertension, kidney problems, osteoporosis, new unexplained headache, persistent vomiting, increased bowel movements or muscle weakness.

The course of Graves’ disease is variable. The majority of patients experience variable periods of hyperthyroidism that alternate with variable periods of remission. Usually, patients have a few predominant symptoms, and these symptoms can change over time. Waxing and waning is the term used to describe the typical disease course in Graves’ disease. Symptoms tend to worsen during periods of stress, and many experts describe stress as the most significant trigger for Graves’ disease.

Studies show that without treatment up to one third of patients will have a spontaneous remission. It’s thought that many people with Graves’ disease have a mild course that’s never diagnosed. About twenty percent of Graves’ disease patients will spontaneously move into mild hypothyroidism. This condition, like the hyperthyroidism, can also resolve on its own when thyroid antibody production ends.

Most patients, except in the case of subclinical Graves’ disease, receive treatment to prevent symptoms from worsening. The goal of therapy in Graves’ disease is to reduce thyroid hormone production either with meds known as anti-thyroid drugs or with aggressive procedures that limit the amount of thyroid tissue available to produce thyroid hormone. Meds have the advantage of mildly suppressing the immune system, helping patients achieve remission.

The early course of Graves’ disease is reported to be one of hypothyroidism. Most of these patients are not diagnosed with hypothyroidism but realize this in retrospect, after they develop hyperthyroidism and compare early symptoms and lab results. Some patients also have extended periods of overt hypothyroidism and have been on replacement hormone for many years before they develop Graves’ disease.

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