Triaging and managing complex, unexpected pathologies is all part of being an ophthalmologist.
One particularly complex condition is anterior uveitis. Mastering the diagnosis and management of this disease can lead to better visual outcomes and fewer complications for patients. In order to do this, understanding the definition, pathology, and management of anterior uveitis is critical.
As a bit of background, the Standardization of Uveitis Nomenclature (SUN) system categorizes intraocular inflammation into anterior, intermediate, posterior, and panuveitis. The definition of these depends on the exact location of involvement of the ocular structures. For anterior uveitis, the SUN system requires the majority of inflammation be contained within the iris and ciliary body. There may be a small amount of inflammation spillover into the vitreous cavity or macular edema posteriorly.
Additionally, every new patient to you (even if they have been diagnosed with anterior uveitis before) or any patient presenting in an unexpected way on follow-up should be dilated to evaluate for intermediate, posterior, or panuveitis. This is imperative, since it can broaden the differential and change the type of management.
Uveitis Challenges
Diagnosing and managing uveitis can be difficult: patients can be light sensitive; pediatric patients can be difficult to examine in the clinic, or they may not come in with a complete history. Keeping the main differential in mind for anterior uveitis can be helpful to determine work-up and treatment plans.
Approaching the Differential
The most common etiologies of noninfectious anterior uveitis are idiopathic (again, this requires the exclusion of noninfectious and infectious causes). Of the known etiologies, common causes include HLA-B27-associated inflammation, sarcoid, syphilis, tuberculosis, viral (herpes simplex, varicella zoster, cytomegalovirus, rubella), inflammatory bowel disease, psoriatic arthritis, and tubulointerstitial nephritis.
Patients with HLA-B27-associated disease can present with explosive anterior uveitis and an impressive hypopyon. These patients may also have characteristic lower back pain, or findings of ankylosing spondylitis. They can also reveal a positive review of systems consistent with inflammatory bowel disease, psoriatic arthritis, or reactive arthritis (which may occur as a sequalae to infectious exposure, such as chlamydia).
Sarcoid-associated anterior uveitis can have a myriad of presentations, and evaluation should include a chest imaging for sarcoidosis involvement, and laboratory investigations for angiotensin converting enzyme. Ocular examination can also identify yield lacrimal gland involvement in these patients, which would demonstrate with an enlarged gland. Often in patients with suspected sarcoidosis, it is difficult to prove systemic involvement, and the involvement of a rheumatologist can be helpful.
There are certain clues that can lead to diagnosing viral etiologies, including transillumination defects of the iris, elevated intraocular pressure, and stellate keratic precipitates on the endothelium. Managing these patients can require sending an aqueous chamber sample for viral polymerase chain reaction (PCR) and initiating systemic antiviral medications.
Patients with tubulointerstitial nephritis can present with abnormal kidney function and may require renal evaluation.
Look for Trauma
In any patient presenting with presumed traumatic iritis, make sure to assess for the presence of ruptured globe or retained foreign body. Clues that can suggest intraocular foreign body or ruptured globe include a peaked pupil, iris transillumination defects, iris heterochromia, and focal cataract. (Figure 1).
Figure 1: A patient with the diagnosis of traumatic iritis. Examination revealed anterior chamber cell, but also showed a corneal laceration with iris plugging the wound, and peaked iris contour. Ocular imaging revealed a retained intraocular foreign body.
Consider Masquerades
Other less common etiologies include medication induced, traumatic iritis, and masquerade conditions, including lymphoma and diffuse retinoblastoma (Figure 2), chronic endophthalmitis, and uveitic glaucoma hyphema syndrome (UGH).
Diffuse retinoblastoma should be considered, especially in the case of a pediatric patient presenting with a hypopyon, particularly in an eye where the conjunctiva appears white or less injected than would be expected for a hypopyon.
Both chronic endophthalmitis and UGH syndrome can occur in patients after cataract surgery. In chronic endophthalmitis, indolent inflammation may worsen with topical steroid therapy and require an aqueous chamber sample. Remember that these pathogens are typically slow-growing and require an extended hold in the laboratory to grow the bug. In cases of UGH syndrome, identification of a large amount of pigment release, iris transillumination defects, and ultrasound biomicroscopy can be particularly helpful to identify lens tilt.
Figure 2: Slit lamp photograph of a 9-year-old female presenting with impressive hypopyon, collections of white blood cells along the peripheral iris, layered hemorrhage, elevated intraocular pressure and very little injection of the sclera. Investigation revealed vitreous cells, and work-up revealed the diagnosis of diffuse retinoblastoma. Image courtesy of Dr. G. Baker Hubbard.
Approaching Treatment
Most cases of noninfectious anterior uveitis will improve with topical steroids. In those that do not respond to topical steroids, consider the possibility of an infection or masquerade syndrome before increasing therapy. In patients that require escalation of therapy, oral steroids, local steroids, and immunosuppression are all options.
Despite appropriate and timely treatment, anterior uveitis carries with it an array of complications that should be assessed and monitored. These include, but are not limited to, macular edema, posterior synechiae, cataract, glaucoma, and epiretinal membrane.
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About the author: Sruthi Arepalli, MD, is a vitreoretinal surgeon and uveitis specialist at Emory University. She completed her residency and vitreoretinal fellowship at the Cleveland Clinic and her uveitis fellowship at the Casey Eye Institute. She currently serves as an associate program director for the Emory ophthalmology residency. She joined the YO Info Editorial Board in 2024. |