EyeWorld Asia-Pacific December 2011 Issue

35 December 2011 EW UVEITIS glaucoma, and chemical injury. It may also be drug-related, such as with topiramate and rifabutin, or part of a masquerade syndrome, associated with conditions such as chronic myeloid and acute lymphoblastic leukemia, metastatic carcinoma, retinoblastoma, and melanoma. The management clearly differs significantly depending on etiology, and a history of recent surgery or trauma can be helpful; when in doubt, said Dr. Lim, treat each case as infectious, but beware of atypical hypopyon from masquerade syndrome. He added that hypopyon is particularly rare in young children; masquerade should be suspected in such cases. Approaching hypertensive anterior uveitis Prof. Chee, returning to the podium for her second lecture, said that hypertensive anterior uveitis refers to patients who are diagnosed with acute anterior uveitis already with increased IOP, rather than patients who present with IOP later, after the onset and diagnosis of uveitis. The danger here is that the raised IOP can confound a clinician’s diagnosis, overshadowing other signs and symptoms, leading to a referral to a glaucoma specialist, potentially missing a sight-threatening condition. Once again, the distinction between infectious and noninfectious etiologies in such cases is crucial. Infections can be caused by parasites, syphilis, toxoplasmosis, and viruses, including herpes viruses and cytomegalovirus (CMV). Viral infections tend to be unilateral, with sudden onset (though insidious if with CMV or rubella); most cases are self- limiting, but recurrent. Noninfectious hypertensive anterior uveitis cases include Schwartz-Matsuo syndrome and sarcoidosis; however, Prof. Chee advised clinicians to “always think of infections.” Investigations such as aqueous PCR and viral serology are not always available, but it is possible to make the diagnosis clinically by a close eye exam: Infectious cases are associated with iris atrophy and corneal changes, with some unusual keratic precipitate patterns; noninfectious cases such as sarcoidosis may have associated changes in the vitreous and retina. Retinal vasculitis A full ocular exam is also essential in approaching cases of retinal vasculitis, said Gemmy Cheung, MD, consultant of the service. She said that these cases are “not isolated in real life”; talking practically about retinal vasculitis is somewhat problematic given that, in practice, these conditions tend to be asymptomatic, often painless with only a nonspecific decrease in visual acuity and occasional floaters to indicate the possibility; hence, patients are more likely to present with other pathologies first, and the clinician will have to look closely into the eye to make this diagnosis. Given that symptoms might not be very indicative, clinicians should focus on finding the signs, which have to do with the retinal vessels. “First we think about the vessels, then we think around the vessels—what happens when the vessels become inflamed,” said Dr. Cheung. The signs include vascular sheathing, frosted, congested, attenuated, occluded, and new vessels. These, said Dr. Cheung, lead to disruptions to the blood supply, in turn creating cotton-wool spots, retinal and vitreous hemorrhages, and optic disc and macular edema. It is important to remember, she said, that noninflammatory retinal vasculopathies—such as atherosclerosis, congenital diseases like Coate’s, hyperviscosity syndrome, diabetes and sickle cell disease—are “much, much more common”. Moreover, retinal vasculitis secondary to ocular diseases such as pars planiitis, intermediate uveitis, chorioretinal inflammation and systemic diseases involving small and medium vessels are much more common than primary disease (Eale’s disease), so clinicians should rule out secondary disease first. Retinal vasculitis, said Dr. Cheung, is “not all the same”; some cases are non-sight-threatening and may not even need intervention, while others are rapidly blinding. The etiology, she said, is important, and careful examination of each case is important. ‘Snowballs and other UFOs’ Vitritis can hamper evaluation of the retina in some cases with retinal vasculitis; however, vitritis itself provides important signs of disease, possibly manifesting in all anatomical types of uveitis— in severe anterior, posterior, and intermediate uveitis. Vitritis can manifest as “snowballs” or “strings of pearls”— collections of inflammatory cells in the vitreous. These snowballs and strings of pearls, said Dr. Chan, returning to the podium for her second lecture of the day, differ depending on etiology. Like keratic precipitates, it is therefore important to characterize the snowballs, strings of pearls, and other “unidentified flying objects”—such as pseudopodia lentis and glass wool veils—in the vitreous. However, she added, diagnosis may require a vitreous biopsy for histological examination. Retinitis vs. choroiditis Although the distinction is important for management purposes, both retinitis and choroiditis, said Bobby Cheng, MD, part- time specialist consultant for Bobby Cheng, MD Gemmy Cheung, MD the service, indicate “a kind of uveitis that is more difficult to handle”; furthermore, these cases are associated with more systemic complications. It is possible to distinguish the two conditions through close visual examination of the retina: choroiditis is deeper, resulting in yellowish lesions visible through the retina; these lesions may be serpiginous, or may appear as discrete nodules. Retinitis is more superficial, resulting in white lesions with fluffy, indistinct borders, and associated with retinal vasculitis. The possible etiologies of the two conditions can differ significantly, though they also intersect in some cases, sometimes leading to chorioretinitis, which will include a mix of the typical lesions from each condition. Infectious choroiditis can be caused by conditions like tuberculosis, toxoplasmosis, toxocara, and syphilis; noninfectious causes include VKH, sarcoidosis, multifocal choroiditis, birdshot, and punctate inner choroidopathy. Infectious retinitis can be caused by CMV, cat scratch disease, acute retinal necrosis, and progressive outer retinal necrosis, but also tuberculosis and syphilis. Noninfectious causes include Behcet’s disease and autoimmune conditions. Once again, beyond simply distinguishing between choroiditis and retinitis, making the distinction between infectious and noninfectious etiologies is essential to effective management. EW Editors’ note: None of the speakers have any financial interests related to their lectures. Contact information Chan: Anita.Chan@snec.com.sg Chee: Chee.Soon.Phaik@snec.com.sg Cheng: Bobby.Cheng@snec.com.sg Cheung: Gemmy.Cheung@snec.com.sg Lim: weekiak@starhub.net.sg