Orbital Inflammation
THYROID EYE DISEASE
Thyroid eye disease (TED) is the most common cause of proptosis in adults. The disease can range from mild eyelid retraction to severe proptosis with optic nerve compression and corneal exposure. Early in the disease course, TED can be difficult to diagnose, but later the ocular signs become classic.
Epidemiology and Etiology
• Age: Rare in children, mainly adults
• Gender: Women affected six times more often than men
• Etiology: Poorly understood autoimmune inflammatory process that affects the eyelid and orbital tissues
History
• Initial onset of nonspecific ocular irritation followed by eyelid retraction, lid lag, eyelid swelling, and bulging of the eyes.
• Patients will note symptoms to be worse in the morning and improve over the day. Many patients will have the history of a systemic thyroid imbalance, but up to 30% may be euthyroid at the onset of symptoms.
Examination
• The earliest signs of TED are very nonspecific, and it can be difficult to make the diagnosis early in the course of the disease.
• Eyelid retraction and eyelid lag are also early signs that will help confirm the diagnosis.
• As the disease progresses, chemosis, proptosis, and motility restriction with diplopia will become apparent.
• Late signs are decreased vision from optic nerve compression and severe corneal exposure (Fig. 12-1A-F).
Imaging
• Computed tomography (CT) scan will show enlargement of the rectus muscles with tendon sparing.
• The inferior rectus is the most commonly involved muscle followed by medial rectus and superior rectus.
• The lateral rectus is rarely involved. CT scan is not needed to make the diagnosis of TED, because this is a clinical diagnosis.
• CT scanning is helpful to confirm unusual cases, evaluate optic nerve compression, and before surgery or irradiation (Fig. 12-1G and H).
Special Considerations
• The course and severity of disease is widely variable.
• Some patients may have a few months of mild inflammation without any sequelae, whereas others can have severe inflammation that can lead to severe proptosis, double vision, and visual loss over a few months or years.
• Patients who smoke have a longer and more severe course.
Differential Diagnosis
• Orbital pseudotumor
• Orbital cellulitis
• Orbital lymphoma
• Orbital arteriovenous malformation
Laboratory Tests
• T3, free T4, thyroid-stimulating hormone
Pathophysiology
• A chronic inflammatory process with orbital fibroblast being the primary target of the inflammatory process. This leads to upregulation with inflammation and increased production of hyaluronan and glycosaminoglycan in the muscles and orbital fat with eventual scarring and dysfunction of these tissues. The complex details of this immune process continue to be worked out.
Treatment
• Limiting the inflammation will reduce the scarring and severity of the disease.
• Systemic steroids will decrease inflammation, but because of the side effects from long-term use, they are usually limited to use as a temporary, short-term treatment.
• Orbital irradiation in some patients is effective at stopping the progression of the disease but not at reversing any of the changes that have occurred.
• Any patient with significant, active disease is a potential candidate for irradiation (except patients with diabetic retinopathy).
• The use of orbital irradiation is controversial.
• Steroid injections into the orbit and a short course of high-dose IV steroids are other treatments.
• Immune modulators such as rituximab are also being explored to stop this autoimmune process. The various biologic agents may hold the key to halting this inflammatory process before significant orbital changes occur.
• After the inflammatory phase is over, surgical correction of residual proptosis, diplopia, and eyelid deformities can be considered.
• This is done via a combination of orbital decompression and eye muscle and eyelid surgery.
• Patients presenting with severe inflammation and an optic neuropathy or corneal decompensation may require an urgent orbital decompression.
Prognosis
• Good, but some patients may require multiple surgical procedures over years as part of the treatment. Patients with significant disease often have a prolonged course of treatment. Smokers have a longer and more severe course.
 FIGURE 12-1. Thyroid-related ophthalmopathy. A. A patient with very early thyroid-related ophthalmopathy with slight lid retraction on the left. B. In down gaze, there is eyelid lag. C. A 20-year-old patient with severe proptosis, eyelid retraction, and corneal exposure. |
 FIGURE 12-1. (continued) D to F. A 45-year-old patient with progressive swelling of the eyes with double vision and recent decreased vision. There is proptosis, chemosis, and limitation of motility. Vision was 20/80 from optic nerve compression. |
 FIGURE 12-1. (continued) G and H. Computed tomography scans show enlargement of all rectus muscles with crowding at the orbital apex. The patient required an orbital decompression, and her vision returned to normal. |
 FIGURE 12-1. (continued) I. A patient with severe thyroid-related ophthalmopathy. J. After 3 years and multiple surgeries, there is significant improvement. |
IDIOPATHIC ORBITAL INFLAMMATION (ORBITAL PSEUDOTUMOR)
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
