Eyeworld

EW CORNEA 34 September 2011 Eyeing reports on post- transplant fungal infections F ungal infection after ker- atoplasty is one of those worries that has been on the rise of late, according to David B. Glasser, M.D., assistant professor of ophthalmol- ogy, Johns Hopkins University, Baltimore, and in private practice, Columbia, Md. "There have been a number of reports in recent years of fungus after endothelial keratoplasty in particular and a general percep- tion among surgeons that perhaps it's more common than what we were seeing after penetrating kerato- plasty," he said. With such concerns in mind, at the recent 50th anniversary of the Eye Bank Association of America in Tucson, Ariz., three reports commis- sioned by the medical advisory board of which Dr. Glasser is chair were given. Eye Bank Association reporting system The first talk, presented by Anthony J. Aldave, M.D., associate professor of ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, looked at the adverse reactions reported through the Eye Bank Association's online adverse re- action reporting system. Dr. Aldave agreed that it is more the perception than the reality that fungal infections have ticked up after keratoplasty. In 2005 the rate of fungal infection associated with tis- sue distributed for U.S. tissue banks was 0.014; in 2010 this was 0.012. "There seems to be an increase in the number of publications, and I think that's what's leading most peo- ple to think it's becoming more common," he said. "Another thing that might be associated with the perceived increase is that we are now performing more partial thickness corneal transplants than we were previously." Dr. Aldave pointed out that the rate of fungal infection after partial thickness graft transplant surgery is 0.022% compared with a rate of 0.012% for full thickness trans- plants. "It's probably because if you get fungi in the interface between the patient's donor and host, it can evade the immune system better than if it's a fungus that is in the tis- sue that's exposed to the aqueous humor in which you have some cir- culating immune surveillance like white blood cells," he said. Investigators continue to delve into where the infections may be coming from. EBAA evidence points to the donor rather than the host. Dr. Aldave shared what usually hap- pens to the donated mate cornea. "If we look at the 31 cases that we have reported in the last 4 years of fungal infection and we look at what hap- pened to the other cornea from the same donor, fungal cultures were by Maxine Lipner Senior EyeWorld Contributing Editor Trekking into the fungal jungle after keratoplasty International point of view Chennai, India Amar Agarwal, M.S., F.R.C.S., F.R.C.Opth. (pictured) and Dhivya Ashok Kumar, M.D. Post-penetrating keratoplasty (PK) fungal in- fections, though uncommon, are chal lenging for the physician. In India, elderly patients with immunosuppression and sys- temic conditions like diabetes are prone to this risk. Farmers and patients with poor hy- giene are also predisposed. Sometimes we encounter patients who have been misdiag- nosed with bacterial infection and a few cases of overuse of steroids. In those patients who have a history of treatment with topical steroids after infection, clinical features typical of fungal infection are generally masked. In our facility, any patient with post-PK infiltrates in the cornea un- dergoes corneal scraping for both bacterial and fungal growth. Fungal hyphae are immediately seen under electronic microscope in KOH mount. Once fungal hyphae are seen, topical treatment is started. How- ever, the species identification is done while growth is seen in Sabouraud's medium after incubation for 2 weeks. Meanwhile, empirical treatment with topical 5% natamycin and 0.05% amphotericin is started. Initial dose is started with a loading dose of antifungal drops every 15 minutes for 2 hours followed by hourly application. Any pa- tient with confirmed fungal infection is reviewed every 12 hours for in- creases in size of infiltration and depth of corneal and scleral involvement. Aspergillus fumigatus is the common fungus species grown from the infected specimen. Recently, topical voriconazole 1% has shown to produce good clinical improvements in fungal infections. Sys- temic (oral) fluconazole is usually advised in suspected fungal cases. Advanced fungal infections can lead to scleral necrosis or corneal melting. Focal corneal abscess can also occur. Corneal abscess or melting will require replacement of the corneal graft (Figure 1). Auto-eviscera- tion of intraocular contents after post-PK infection due to corneal melt- ing has also been seen in our practice. In localized corneal infection, intrastromal voriconazole can be given. When all treatment fails and the lesion progresses, therapeutic PK is recommended. We have also seen secondary endophthalmitis after fungal keratitis. Chances of recurrence of fungal infection in the graft after therapeutic PK are possible. Hence it is better to in- form the patient of the prognosis and complications. Suture-related or ocular sur- face problems and persistent ep- ithelial defects can act as significant local risk factors in post-PK graft infections. A loose or broken suture left unattended may lead to epithelial defect, which, in turn may result in a mu- coid deposit developing around it, and a nidus for micro-organisms. It is therefore essential that any loose or broken sutures be removed as early as possible. Although infection is found to be more common in patients belonging to a lower socioeconomic group, the role of economic status is not significant. In our experience, distance from care is a greater prob- lem; rural patients who have to travel farther to reach the city-based ter- tiary centers more frequently face problems. However, good clinical slit lamp evaluation of post-op patients can diagnose fungal infection in the early stage. Regular use of topical medications and treatment of the pre- disposed condition is necessary. EW Editors' note: Dr. Agarwal is the director of Dr. Agarwal's Eye Hospital and Eye Research Centre in Chennai, India. Dr. Kumar is a consultant in oculoplasty, uveitis, and anterior segment diseases at Dr. Agarwal's Eye Hospital. Contact information Agarwal: dragarwal@vsnl.com Figure 1. Post-penetrating keratoplasty corneal melting with abscess Source: Amar Agarwal, M.S., F.R.C.S., F.R.C.Opth., and Dhivya Ashok Kumar, M.D.

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