Fusarium infection complicating rheumatic keratitis that acutely progressed to endophthalmitis during regular infusion of tocilizumab: a case report

BACKGROUND: Filamentous fungi are ubiquitous in plants, water, and soil. The predominant fungi that infect the human cornea include Fusarium and Aspergillus species. The onset of fungal endophthalmitis is indolent, and typically takes weeks to months to develop after corneal infection. We report a case of Fusarium infection complicating rheumatic keratitis that acutely progressed to endophthalmitis during intravenous tocilizumab therapy. CASE PRESENTATION: A 65-year-old female patient was referred to our department due to pain and decreased vision in her left eye. Slit-lamp examination showed a white focus on the upper peripheral cornea, hypopyon, anterior chamber fibrin formation, marked ciliary hyperemia, and whole corneal epithelial defects. As the corneal scraping smear was positive for filamentous fungi and Fusarium species were detected by aqueous humor polymerase chain reaction, anti-fungal therapy was started. Although the initial response to anti-fungal therapy was good, we observed corneal infiltration, worsening hypopyon, and vitreous opacity after tocilizumab infusion. Given that the infection continued to progress despite conservative therapy, we performed penetrating keratoplasty combined with vitrectomy. After removal of the white focus beneath the intraocular lens, a temporary corneal prosthesis was mounted and the dense vitreous opacity was removed. Finally, a frozen donor graft was sutured in place. The corneal infiltration, hypopyon, and vitreous opacity all disappeared after the operation. CONCLUSION: The rapid progression of Fusarium keratitis to endophthalmitis in a patient who was receiving a regular infusion of tocilizumab demonstrates that ocular condition should be closely monitored during systemic tocilizumab administration due to increased risk of infection.