Thyroid eye disease (NORD)

Definitions & Key takeaways

Thyroid eye disease is a rare autoimmune disorder that affects the muscles and tissues around the eyes. It is caused by an overactive thyroid gland where there is a progressive inflammation that damages tissues around the eyes. Signs and symptoms of thyroid eye disease include eye redness, eye swelling out of the eye socket, called exophthalmos, and bulging, as well as double vision and sensitivity to light. Treatment may involve medications like corticosteroids, immunosuppressive drugs, and in some cases, orbital decompression surgery to relieve pressure on the eye.

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Thyroid eye disease is a rare disease in which progressive inflammation damages muscle, fat and connective tissues around the eyes.
The disease has an active phase, which can last from six months to two years, where inflammation, swelling, and damage occur.
The inactive phase occurs when disease progression stops, but the tissue damage and symptoms remain. Signs and symptoms can vary between individuals, but commonly the white parts of the eyes are inflamed.
A particularly noticeable change is the eyes appear to be bulging out of the eye socket, called exophthalmos or proptosis, which makes a person appear as if they are always ‘staring’.
Additionally, the eyes can feel irritated, uncomfortable, and have a “gritty” feeling. They may also be constantly watery or be dry.
The eyelids can become inflamed and retracted, so they won’t close completely and blinking or trying to close the eyes can be painful.
Vision changes may also occur, including blurry vision; double vision; or an intolerance to bright lights. In severe cases, vision may be threatened from increased pressure on the main nerve of the eye that carries visual information to the brain; or from dryness leading to erosion of the cornea, which is the outer part of the eye.
Thyroid eye disease usually occurs during middle age. While it’s more frequent among females, males tend to have more severe cases.
Environmental factors such as smoking may contribute but there’s also a variety of genetic factors. Individuals may have an elevated risk if they also have immune diseases like type 1 diabetes or rheumatoid arthritis.
Because thyroid eye disease occurs so often with Graves’ disease, it’s also called Graves’ orbitopathy, Graves’ ophthalmopathy, and thyroid-associated ophthalmopathy.
The exact underlying process by which thyroid eye disease occurs is not fully understood, but like Graves disease, it’s an autoimmune disorder.
Normally, the immune system protects the body by identifying and destroying foreign invaders; like bacteria, viruses or toxins.
The adaptive immune system is in charge of creating specialized proteins, called antibodies, that attack and destroy specific invaders.
But in autoimmune disorders, the adaptive immune system mistakenly attacks the body’s own healthy tissues. In thyroid eye disease, the immune system makes abnormal antibodies called thyroid-stimulating immunoglobulin.
And they circulate around the body and attach to specific receptors on the thyroid and other tissues, like those found in the eyes.
Once they attach, the antibodies cause the immune system to attack the eyes leading to inflammation and damage to the eye’s muscle, fat and connective tissues.
Individuals who develop thyroid eye disease also have an increased expression of insulin-like growth factor 1 receptor, abbreviated IGF-1R, on the tissue around the eye.
Researchers believe this receptor plays a significant role in the development of the disorder. Antibodies against these receptors are produced in people with thyroid eye disease, and once bound to the IGF-1R, they can increase collagen production.
Collagen builds up in the tissue around the eyes causing excessive fibrosis or scar tissue formation. This pushes on nerves, blood vessels and the eye itself.
Diagnosis is based on patient history; and the signs and symptoms of the disease, like changes in the appearance of the eyes and vision changes.
Some clinical tests can assess these changes, like measuring the degree of proptosis with a specialized device called an exophthalmometer, and having an eye exam.
Additionally, medical imaging can also be helpful. Treatment includes teprotumumab which blocks IGF-1R activation.
It’s approved by the FDA for the treatment of thyroid eye disease. Management of underlying diseases that might be affecting thyroid activity, like corticosteroids or prednisone to control inflammation, may be helpful.
Radiation therapy can be an option and so can surgery to remove some of the bone around the eye to relieve pressure or reposition muscles or eyelids.
Supportive treatments include using artificial tears to prevent dry eyes; and eye patches or prisms to reduce double vision.
##Summary As a quick recap: Thyroid eye disease is a rare autoimmune disease in which the immune system produces abnormal antibodies that cause the immune system to attack the tissues around the eyes causing inflammation and damage.
They also increase collagen synthesis and fibrosis around the eyes. Signs and symptoms include changes in the eyes, eyelids, and vision.
Diagnosis is made with clinical tests and medical imaging. Treatments include teprotumumab, corticosteroids, orbital decompression surgery,