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Clinical Characteristics, Histopathology, and Treatment Outcomes of Pythium Keratitis: A Retrospective Cohort Study - PubMed

  • ️Fri Jan 01 2021

Clinical Characteristics, Histopathology, and Treatment Outcomes of Pythium Keratitis: A Retrospective Cohort Study

Vilavun Puangsricharern et al. Clin Ophthalmol. 2021.

Abstract

Purpose: To identify factors associated with the prognosis in Pythium keratitis.

Patients and methods: The medical records of 25 patients (26 eyes) diagnosed with Pythium keratitis at a referral institution were reviewed. The demographic and clinical characteristics, treatment, microbiological diagnosis, histopathological features, and outcomes were recorded. The histopathological specimens were reviewed. The patients were divided into a globe removal group and a globe salvage group. Univariate analysis was used to identify factors associated with poor outcomes.

Results: Fifteen eyes (57.7%) were removed. Patients in the globe removal group were on average 16.4 years older (95% CI 6.98 to 25.88) than those in the globe salvage group, received the first medication (either topical antifungals or antibiotics) later than one day after the onset of symptoms (RR = 2.75, 95% CI 1.18 to 6.42), and had a maximal diameter of the infiltration area ≥6 mm (RR = 3.14, 95% CI 1.17 to 8.45). The globe removal group showed satellite, multifocal, or total corneal infiltration patterns (RR = 2.82, 95% CI 1.03 to 7.74) and a hypopyon (RR = 3.43, 95% CI 1.26 to 9.35) as risk factors. The histopathological examination showed a higher density of Pythium in the globe removal group than the globe salvage group (median 376 (interquartile range 323, 620) versus 107 (interquartile range 16, 260) hyphae per high power field; P = 0.035).

Conclusion: The risk of globe removal in patients with Pythium keratitis increased with age, delayed initial topical antifungal or antibiotic treatment, advanced disease at presentation, and dense Pythium hyphae infiltration of the cornea. Early recognition and treatment are critical to successfully eradicate the infection.

Keywords: eye evisceration; eye infections; keratoplasty; oomycetes; penetrating; prognostic factors.

© 2021 Puangsricharern et al.

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Conflict of interest statement

The authors have no conflicts of interest to declare.

Figures

Figure 1
Figure 1

Diagrams of infiltration pattern and clinical slit-lamp photographs. (A1 and A2) Diagram of a reticular infiltration pattern and a photograph of a 21-year-old student who had a history of contact-lens wearing and presented at KCMH two days after left eye irritation (Case#21); (B1 and B2) diagram of a satellite infiltration pattern and a photograph of a 55-year-old farmer who had a trauma to the right eye from grass leaves (Case#15); (C1 and C2) diagram of a multifocal infiltration pattern and a photograph of a 58-year-old farmer who had a trauma of the right eye with soil contamination (Case#24); (D1 and D2) diagram of a total infiltration pattern and a photograph of the right eye of a 61-year-old female without a significant history of ocular trauma (Case#10).

Figure 2
Figure 2

Box plot demonstrates that almost all of the cases from the globe salvage group received their first medical treatment on day 1 after onset of symptoms (asterisks indicate extreme outliers).

Figure 3
Figure 3

Histopathology of Pythium keratitis in a globe salvage case (Case#19). (A) Histopathology section shows an ulcerated corneal lesion with numerous acute inflammatory cells and necrotic cells primarily located at the anterior stroma (Hematoxylin-Eosin); (B) special stain shows varying sizes of short hyphae at the posterior stroma and pre-Descemet’s membrane area (Gomori Methenamine Silver).

Figure 4
Figure 4

Histopathology of Pythium keratitis in globe salvage case (Case#05). (A) Histopathology section shows numerous acute inflammatory cells and necrotic cells in the corneal stroma (Hematoxylin-Eosin); (B) special stain shows varying-sized short hyphae at the mid stroma (Gomori Methenamine Silver).

Figure 5
Figure 5

Histopathology of Pythium keratitis in globe removal case (Case#23). (A) Histopathology section shows numerous acute inflammatory cells and necrotic cells in the corneal stroma (Hematoxylin-Eosin); (B) special stain shows numerous varying-sized short hyphae with rare septation (Gomori Methenamine Silver).

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