Graves' Ophthalmopathy And Pretibial Myxedema

What is Graves' ophthalmopathy?

In Graves' ophthalmopathy, (GO,) your eyeball bulges out past its protective orbit (exophthalmos). This occurs as tissues and muscles behind your eye swell and cause your eyeball to move forward. Because your eye is so far forward, the front surface of your eye can become dry. Up to 80% of patients with Graves' disease develop eye symptoms. GO may occur long before, at the same time as, or long after thyroid disease is diagnosed and treated. Although most patients with Graves' disease have Graves' ophthalmopathy, about 10% of patients with GO have normal thyroid function.

Common Symptoms

• Excess tearing and sensation of grit or sand in either or both eyes
• Reddened or inflamed eyes
• Widening of the space between your eyelids
• Swelling of the lids and tissues around the eyes
• Light sensitivity

Other Less Common Symptoms

• Ulcers on the cornea
• Double vision
• Limited eye movements
• Blurred or reduced vision

Treatments

• Treat underlying thyroid dysfunction.
• Lubricants and punctal plugs/cauterization for dry eyes.
• corticosteroids, radiation, and/or surgical orbital decompression.
• Prisms or strabismus surgery for diplopia, (double vision.)

What is Graves' dermopathy or Pretibial Myxedema?

Pretibial myxedema is a skin condition that may develop in patients with Graves’ disease. It is characterized by thickening of a layer of tissue that lies directly beneath the surface of skin called the dermis. The word “pretibial” refers to the fact that this thickening usually involves the skin that covers the front of the tibia bone in the lower leg. Other terms used to identify this disorder include localized myxedema and thyroid dermopathy.

Pretibial myxedema usually becomes evident when raised lesions begin to appear on the skin that covers the front surfaces of the shins. These lesions are usually light in color, though they may darken over time. They are usually painless, though they may occasionally cause some itching. Hair follicles in these lesions may become very prominent, giving the overlying skin an appearance and texture that resembles an orange peel. Increased perspiration may also be noted. In most cases of pretibial myxedema, continued growth of lesions leads to widespread thickening of the skin that covers the front surfaces of the shins. In some cases limited growth of lesions may be associated with the emergence of circumscribed raised lesions called plaques or nodules. In rare cases, lesions may grow to the point where they block the flow of fluid through the lymphatic vessels. This may lead to severe swelling of the limbs. Although myxedema most commonly develops along the front surfaces of the shins, it may also involve the feet and toes. It is less likely to develop in other locations, though cases have been reported that have presented with thickening of skin along the arms, hands, fingers, back, ears, and nose.

On the whole, pretibial myxedema represents a relatively rare complication of Graves’ disease. When it does develop, it is often associated with thyroid eye disease. It is more common among women. In rare cases, patients diagnosed with Graves’ disease may develop isolated thyroid eye disease and pretibial myxedema without any evidence of thyrotoxicosis or hyperthyroidism. This condition is called euthyroid Graves’ disease.

Treatment

Most patients who develop mild pretibial myxedema do not require any specific treatment. Some patients who develop moderate pretibial myxedema may need to be treated if they develop problems with pain, disfigurement, or impaired motion of the feet or ankles. In such cases, treatment usually focuses on the direct application of glucocorticoids. Glucocorticoids are steroid hormones that are similar to a hormone produced by the adrenal glands called cortisol. They help to reduce inflammation by blocking the movement of white blood cells that infiltrate tissues. A glucocorticoid in a cream base can usually be applied directly to any areas of thickened skin. For the sake of convenience, this is usually done at bedtime so that areas of thickened skin covered with the cream base can be bound with plastic wrap. This may help to increase the penetration of the glucocorticoid. If applications are continued on a regular basis, gradual improvement in appearance and function may be noted over the course of several weeks. The effectiveness of treatment may be increased if compression stockings are worn during the daytime to limit the accumulation of fluid in the lower legs and feet. In rare cases of severe myxedema, surgery with skin grafting may be considered to remove enlarging lesions that do not respond to applications of glucocorticoids.