Graves' disease is an autoimmune disease. It most commonly affects the thyroid, frequently causing it to enlarge to twice its size or more (goiter), become overactive, with related hyperthyroid symptoms such as increased heartbeat, muscle weakness, disturbed sleep, and irritability. It can also affect the eyes, causing bulging eyes (exophthalmos). It affects other systems of the body, including the skin, heart, circulation and nervous system.
It affects up to 2% of the female population, sometimes appears after childbirth, and has a female:male incidence of 5:1 to 10:1. It has a strong hereditary component; when one identical twin has Graves' disease, the other twin will have it 25% of the time. Smoking and exposure to second-hand smoke is associated with the eye manifestations but not the thyroid manifestations.
Diagnosis is usually made on the basis of symptoms, although thyroid hormone tests may be useful, particularly to monitor treatment
Thyroid-associated ophthalmopathy is one of the most typical symptoms of Graves' disease. It is known by a variety of terms, the most common being Graves' ophthalmopathy. Thyroid eye disease is an inflammatory condition, which affects the orbital contents including the extraocular muscles and orbital fat. It is almost always associated with Graves' disease but may rarely be seen in Hashimoto's thyroiditis, primary hypothyroidism, or thyroid cancer.
The ocular manifestations that are relatively specific to Grave's disease include soft tissue inflammation, proptosis (protrusion of one or both globes of the eyes), corneal exposure, and optic nerve compression. Also seen, if the patient is hyperthyroid, (i.e., has too much thryoid hormone) are more general manifestations, which are due to hyperthyroidism itself and which may be seen in any conditions that cause hyperthyroidism (such as toxic multinodular goiter or even thyroid poisoning). These more general symptoms include lid retraction, lid lag, and a delay in the downward excursion of the upper eyelid, during downward gaze.
As the disease progresses, the muscles enlarge and the fat as may as well; this may lead to (1) the eye bulging forward and (2) compression of the optic nerve.