Therapeutic penetrating keratoplasty with adjunctive bevacizumab was followed by infection control, reduced corneal neovascularization, and improved visual acuity in a patient with severe keratitis involving culture-confirmed Pseudomonas aeruginosa and suspected Acanthamoeba infection.
Researchers described a 27-year-old female patient who presented with a 48-hour history of intense ocular pain, photophobia, and reduced vision in her left eye. The patient wore monthly soft contact lenses for myopia and astigmatism, frequently extended their use beyond the recommended duration, occasionally wore them overnight, and reported inconsistent replacement of lens storage solution. The researchers documented the clinical course using slit-lamp examinations, microbiological cultures, polymerase chain reaction (PCR) testing, in vivo confocal microscopy, and postoperative imaging.
At presentation, best-corrected visual acuity was 10/10 in the unaffected right eye, whereas pinhole visual acuity was 1/10 in the affected left eye. Slit-lamp examination revealed a central corneal ulcer measuring 2.6 × 2.6 mm, accompanied by stromal thinning, tissue dissolution, and a large epithelial defect. Additional findings included stromal edema, hypopyon, a Wessely immune ring, and radial perineuritis.
Microbiological cultures obtained from corneal scrapings and contact lenses grew P aeruginosa susceptible to amikacin and ceftazidime. Although PCR for Acanthamoeba was negative, confocal microscopy demonstrated hyperreflective cystic structures suggestive of concurrent infection. The researchersconsidered the presentation consistent with presumed polymicrobial keratitis.
Initial treatment included intensive topical amikacin and vancomycin, intravenous ceftazidime, and oral tetracycline. Following the confocal microscopy findings, polyhexamethylenebiguanide and hexamidine were added to address suspected Acanthamoeba infection.
Despite about 2.5 months of intensive antibacterial and antiamoebic treatment, the patient continued to demonstrate a persistent epithelial defect, stromal instability, and progressive corneal neovascularization. Confocal microscopy continued to identify cystic structures at the same stromal locations. Visual acuity remained poor, and neovascularization increasingly involved the visual axis.
As the disease progressed, the researchers identified a substantial risk of corneal perforation and loss of structural integrity. About 4 months postpresentation, the clinical timeline documented advanced central ulceration, extensive superficial and deep neovascularization, and visual acuity reduced to hand motion.
Therapeutic penetrating keratoplasty was performed to remove infected tissue and restore corneal integrity. The procedure involved an 8.5-mm host trephination and an 8.75-mm donor graft secured with 16 interrupted sutures.
To address persistent neovascularization, intrastromal bevacizumab was administered at a dose of 1.25 mg/0.05 mL during surgery, followed by 2 additional injections during postoperative follow-up. The injections targeted neovascular vessels near the graft–host junction while avoiding direct administration into the visual axis.
Postoperative management included oral ciprofloxacin, topical ofloxacin, a tapering course of topical dexamethasone, and ocular lubricants. Antiamoebic therapy was discontinued following surgical excision of the infected corneal tissue, which had achieved clear surgical margins.
At the 3-month postoperative assessment, the corneal graft remained clear and structurally stable, with no evidence of recurrent infection, graft rejection, or other reported complications. Corneal neovascularization had diminished, and pinhole visual acuity improved to 6/10. Postoperative corneal tomography demonstrated stable graft configuration, while endothelial cell analysis showed a preserved endothelial mosaic with reduced cell density.
The researchers emphasized the diagnostic challenges associated with suspected polymicrobial keratitis, particularly when microbiological and imaging findings are discordant. Negative PCR did not eliminate clinical suspicion of Acanthamoeba infection because confocal microscopy demonstrated characteristic cystic structures. The researchers discussed the possibility that interactions between P aeruginosa and Acanthamoeba could contribute to aggressive corneal inflammation and tissue destruction, drawing on previously published experimental evidence.
Several limitations warrant consideration. The report described a single patient, limiting the generalizability of the clinical findings. Concurrent Acanthamoeba infection was supported by confocal microscopy but was not confirmed by PCR, and histopathologic examination of the excised corneal tissue was not performed. Because penetrating keratoplasty and bevacizumab were used together, the independent contribution of each intervention to the favorable postoperative outcome could not be established. Follow-up findings were reported through 3 months postsurgery, leaving longer-term graft outcomes uncertain.
“Surgical escalation, a therapeutic penetrating keratoplasty in this case, should be considered promptly and conducted without delay in complex refractory cases,” wrote lead study author IoannaGardeli, MD, of the Cornea and Transplant Department at General Hospital of Athens “Georgios Gennimatas” in Greece, and colleagues.
The study authors reported no conflicts of interest.
Source: Cornea Open