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Quiet eyes with failed PK can harbor asymptomatic infections
An epithelial defect in failed penetrating keratoplasty may be a sign of an infection.
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Epithelial defects in patients with failed penetrating keratoplasty may be a sign of asymptomatic infections, according to a study.
In 53 repeat PK procedures performed at Villa Serena and Villa Igea private hospitals in Forli, Italy, researchers found infections in seven eyes, six of which included epithelial defects, Massimo Busin, MD, told Ocular Surgery News.
“Failed grafts in apparently quiet eyes can harbor slow-growing asymptomatic infections. These infections can recur following repeat keratoplasty and may jeopardize the new grafted tissue. The most common finding in our case series was epithelial defect, which occurred in six out of seven infected eyes, about 86%. While epithelial abnormalities, for example, edema, bullae, calcium deposits, etc, are very common in failed grafts, frank nonhealing epithelial defect should raise the suspicion of an active infection, especially if accompanied by a stromal infiltrate,” he said.
No pain symptoms
Patients were referred for PK due to long-standing issues with graft decompensation and stromal scars or surface irregularities.
The infection rate in the patient cohort was 13.2% (seven of 53 eyes), with six eyes having an epithelial defect, five eyes having focal whitening of the corneal stroma, one eye having crystalline keratopathy and one eye having an elevated pigmented lesion.
None of the patients presented with unusual pain, symptoms or discomfort. Of the eyes with epithelial defects, none previously had herpetic keratitis, lid abnormalities, loose sutures or bandage contact lens. Additionally, no patients were treated with topical steroids at presentation.
In the 46 eyes that did not have an infection, 19 eyes were found to have an epithelial defect.
“From our experience, the three most important factors that make a PK graft, be it primary or a repeat graft, prone to infection are loose sutures, ongoing infection at the time of keratoplasty and, our new finding, any epithelial defect. Moreover, patients with limited understanding or guidance often present late with extensive infection. Therefore, any preoperative factors that can damage the epithelium such as lid abnormalities, trichiasis, etc., should be addressed prior to keratoplasty. Loose sutures that stain with fluorescein or accumulate mucus should be always removed. We also advise that antibiotic drops should be given for a few days following any suture removal, as we had a few cases of infectious keratitis occurring after suture removal,” Busin said.
Infection treatment
Busin said proper guidance should be given to the patient or caretaker so that graft infections or rejections can be diagnosed, referred and treated promptly.
Proper diagnosis should consist of routine cultures and histological examination of the excised corneal button, he said.
If a serious suppurative graft infection is diagnosed, Busin said smears and scrapings should be collected for cultures, and empiric treatment with fortified antibiotics, such as a quinolone, vancomycin or ceftazidime, should be started. Eventually, patients should also receive amphotericin B every hour for at least 2 to 3 days.
“Other groups prefer to start the treatment with a fourth-generation quinolone such as Vigamox (moxifloxacin hydrochloride ophthalmic solution 0.5%, Alcon) and eventually adjust treatment based on the antibiogram. If the clinical picture does not worsen, it means there is an improvement. In other words, if the hypopyon, the stromal infiltration or the epithelial defect does not increase, this is considered an improvement. Sometimes healing of the lesion may require weeks, if not months, to be completed,” he said.
If the response to treatment is unsatisfactory, a corneal biopsy should be completed and further treatment guided by its results, he said. – by Robert Linnehan
- Reference:
- Nahum Y, et al. Cornea. 2017;doi:10.1097/ICO.0000000000001121.
- For more information:
- Massimo Busin, MD, can be reached at Department of Ophthalmology, Villa Igea Hospital, Viale Gramsci 42-44, 47122 Forli, Italy; email: mbusin@yahoo.com.
Disclosure: Busin reports he receives travel expenses, reimbursement and royalties from Moria.