LAKE BUENA VISTA, FLA. – In the face of serious – even vision-threatening – complications, endocrinologists treating patients with Graves orbitopathy should understand when and how surgical options should be considered, according to Dr. Peter J. Dolman, speaking at the 15th International Thyroid Congress.
For most patients, the course of Graves orbitopathy (GO) is likely to follow “Rundle’s curve,” with a rapid progression to the most severe symptoms, and a more gradual abatement of eye symptoms that usually does not return to baseline. About one-third of patients with GO will develop more severe disease, will need intensive medical management, and may require surgical referral. The VISA system, which Dr. Dolman helped develop, classifies thyroid eye disease according to the four criteria of vision/optic neuropathy, inflammation/congestion, strabismus/motility, and appearance/exposure.
During early disease stages, medical management is usually the most effective in quieting the disease course. “The earlier you can treat the patient, the fewer consequences to the orbit,” he said. Later surgical treatment can work to restore alignment, lower the lids, and reduce proptosis. However, when disease severity threatens vision, earlier surgical referral can be needed, said Dr. Dolman, clinical professor in the department of ophthalmology and visual sciences at the University of British Columbia in Vancouver.
Using the VISA assessment system, the first major area of concern is optic neuropathy. This usually happens in the context of pronounced inflammation of retro-orbital contents and also of the eye muscles. In this circumstance, the inflammation crowds and compresses the optic nerve. Decreased color perception can be an early symptom, noted by the patient well before central vision loss, said Dr. Dolman. If compression is unilateral, an afferent pupil defect may be noted. A CT scan will show apical compression of the optic nerve. Clinical activity scores may not rise significantly, so physicians must have a high index of suspicion for optic neuropathy.
In his practice, 85% of patients with GO complicated by optic neuropathy show some improvement on steroids, but Dr. Dolman still performs orbital decompressions on 80% of these patients overall. Radiotherapy may be effective over time as well. Complications of orbital decompression can include CSF leak, intracranial hemorrhage, increased strabismus (experienced by 54% of patients in one study), and the chance of relapse with vision loss (in 8% of patients). Even after surgery, disease progresses in about 30% of patients; therefore, “It’s wise to continue with steroids and radiotherapy after surgery.”
Inflammation and congestion represent the “I” in VISA. In addition to the local inflammatory response, local tissue edema can increase vasocongestion by mechanical means when venules and veins are compressed. The resulting chemosis can exacerbate pain and irritation and make lid closure even more difficult, increasing the risk of corneal damage. Steroids may help relieve chronic congestion and may be useful in those patients in whom exposure is not compromising corneal integrity. But orbital decompression may be needed when the patient’s stabilized GO picture still has a significant congestive component.
Strabismus and eye motility impairment can present a significant impediment in patients’ daily lives. Diplopia can preclude driving, impair reading ability, and even affect ambulation. Initial treatment with steroids and/or radiotherapy during the initial phase may alleviate the tissue inflammation and edema that are impairing muscle function; eye patching should also be used when helpful. Once GO has stabilized, visual correction with prisms may help less severe strabismus, while some patients will need eye muscle surgery to correct alignment.
Eye appearance and risk for corneal damage from exposure are the final considerations in the VISA system. Proptosis may be severe enough that patients cannot fully blink or close their eyes enough to eliminate the palpebral fissure during sleep, risking corneal integrity. If initial treatment with steroids and radiotherapy is not effective – as it will not be in 40%-50% of patients – then surgery should be considered. Options include performing a temporary tarsorrhaphy or an orbit decompression with lid narrowing. Because the surgical approach is different when decompression is performed for proptosis, “complications of decompression are much less common for proptosis than for optic neuropathy,” said Dr. Dolman.
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