Thyroid Eye Disease – My Experience Thus Far

Thyroid-related eye disease doesn’t come up too often in clinic, but I swear that when these patients make eye appointments, they all come on the same day. Last summer, I was at my first third-year rotation and was in with a patient when there was a knock on the door. My colleague from the next room over was in with a patient who had hypothyroidism and he wanted to borrow the exophthalmometer, an instrument for measuring how far the eyes are extruding from their sockets, which was in my room. In thyroid disease (mainly hyper- but also seen in hypo-thyroidism), there can be other clinical systemic manifestations, one of them being thyroid orbitopathy, in which the eye muscles become thickened, forcing the eyes to protrude forward in the eye sockets. Severe manifestations may lead to dry eyes, optic nerve damage, and vision loss in advanced stages. Typically, ocular involvement in thyroid disease is a sign of Grave’s disease, in which striated skeletal muscle is attacked by autoantibodies, leading to eye muscle thickening and/or weakness, in addition to inducing hyperthyroidism(1).

Thyroid orbitopathy is usually measurable via exopthalmometry, so I was happy to hand mine over to my friend so he could get a baseline on his patient. Moments later while I was going through my own patient’s medical history, I found out that he actually had hyperthyroidism and on gross examination, seemed mildly proptotic (a fancy word for eyes protruding from the sockets). I stole my exopthalmometer back and decided it would be a good idea for me to get a baseline reading on him – his reading was high-normal, and this data would be invaluable at his next visit when it is performed again and compared to my initial measurement. Without a baseline to compare to, it is difficult to tell if a patient is stable, or if they are progressing towards thyroid eye disease. For this reason, it is very important to obtain an initial measurement, even if signs are not present at their first visit.

Fast forward to Fall of my third year… my fellow third years and I worked through our patients at clinic one Friday. Two patients I saw back-to-back both had Hashimoto’s thyroiditis, a type of thyroid condition involving systemic autoimmunity against certain tissues, including the thyroid gland and extraocular muscles(1). Unlike Grave’s disease, people with Hashimoto’s thyroiditis typically display hypothyroidism(1), as did my two patients on this day. The two conditions are similar, however, in that they can both result in thyroid orbitopathy and exophthalmos (another fancy word for protruding eyes). Additionally, patients may present with crepitus, or a popping/crackling sound within the eye socket due to infiltrative processes arising from the autoimmune components of these diseases – it can be analogous to abnormal cracking in joints of patients with osteoarthritis. One of my patients this Fall, in fact, did report mild crepitus, although it is not considered a significant finding unless there is a loss of function or if the patient had sustained blunt trauma to the eye and an orbital fracture is suspected.

Much of the treatment involved in thyroid eye disease is to keep the patient comfortable and includes artificial tears, taping the lids shut at night, and smoking cessation. In more severe cases in which inflammation is a component, immune-suppressing drugs or systemic steroids are sometimes implemented. In advanced stages, surgery may be indicated, especially if eye movements are impeded. In some cases, blood tests and imaging studies may be indicated to help aid a clinician’s course of therapy (1). Finally, it is important to emphasize the importance of routine physical and eye exams when talking to patients, so that their symptoms can be effectively managed.

That’s my little ramble on thyroid eye disease, and I hope anyone reading this learned something new!

Sources:
(1) Chapter 7: Orbital Disease. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease. 5th Edition (2008).

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