Hyperthyroidism (Graves' Disease)

Definition

Hyperthyroidism is a disease in which the thyroid gland produces too much thyroid hormone. The thyroid gland is a butterfly-shaped gland in the front of the neck. It produces hormones that control metabolism. The most common form of hyperthyroidism is Graves' disease.

Causes

Graves' disease occurs when your own immune system produces antibodies that stimulate overproduction of thyroid hormone. Other common causes of hyperthyroidism include:

• Thyroid nodules or tumors
• Toxic uninodular goiter—a single nodule in the thyroid gland
• Subacute thyroiditis—inflammation of the thyroid gland (often later leads to hypothyroidism )
• Toxic multinodular goiter—multiple areas in the thyroid gland which overproduce excess amount of thyroid hormone

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors for Graves' disease include:

• Sex: female (eight times more common in women)
• Age: peak incidence between 30-40 years old
• Pregnancy: postpartum thyroiditis (first hyperthyroid followed by hypothyroid)
• History of family members with Graves' disease
• Certain viral infections

Symptoms

Symptoms come on gradually and may be mistaken for stress. As the thyroid becomes more overactive, symptoms may include:

• Fatigue
• Unexplained weight loss with increased appetite
• Restlessness
• Changes in libido
• Muscle weakness and wasting especially in the elderly
• Heat intolerance
• Tremors
• Enlarged thyroid gland (goiter)
• Heart palpitations
• Increased sweating
• Nervousness
• Irritability
• Redness, swelling, and protrusion of the eyes
• Lumpy, reddish thickening of the skin in front of the shins
• Shortness of breath
• Increased number of bowel movements
• Irregular or no menstrual period
• Heart failure or atrial fibrillation , especially in the elderly

Diagnosis

The doctor will ask about your symptoms and medical and family history, and perform a physical exam. The exam usually reveals the following:

• Enlarged thyroid gland
• Rapid pulse
• Warm, moist skin
• Several of the symptoms listed above

Blood tests will be ordered to confirm the diagnosis, including:

• Thyroid stimulating hormone (TSH), currently the best screening test
• Free T4 and free T3
• Thyroid autoantibodies (TSH receptor antibody)

Additionally, a test called a thyroid scan may be needed to help differentiate between Graves' disease and other causes of hyperthyroidism. Your doctor will most likely order a radioactive iodine uptake test, which measures how active your thyroid is in taking up the iodine. Occasionally, a needle biopsy of the thyroid is needed.

Treatment

Treatment will depend on:

• Age
• Severity of symptoms
• Cause of hyperthyroidism
• Pregnancy status

Treatment options include:

Prevention

There are several ways to prevent getting hyperthyroidism including:

• Eat a diet with an adequate amount of iodine.
• Get regular screening for hyperthyroidism if there is someone in your immediate family with this disease or you have another autoimmune disease.