Diagnosis and Treatment of Pythium Insidiosum Corneal Ulcer in a Chinese Child: A Case Report and Literature Review

Abstract

Patient: Male, 7Final Diagnosis: Pythium insidiosumSymptoms: Painful vision loss • red eyeMedication:—Clinical Procedure: Application of multiple antifungal medicines followed by the penetrating keratoplastySpecialty: OphthalmologyObjective:Rare diseaseBackground:Pythium insidiosum keratitis is a rare but sight-threatening disease with a high morbidity rate. It can be mis-diagnosed as fungal keratitis in clinic settings. We report a case of severe Pythium insidiosum keratitis in a Chinese child, treated with combined approaches.Case Report:A 7-year-old boy from Hainan province in the south of China developed a suppurative corneal ulcer after being in a forest. A mass of hyphae was detected by confocal imaging in vivo, fungal smear test, and histochemical examination. Treatment with Natamycin, fluconazole, and Voriconazole for 1 month was unsuccessful, and a penetrating keratoplasty with anterior vitrectomy was performed. The infection reappeared 1 day after surgery, immediately after which anterior chamber irrigation with 0.02% Fluconazole and amphotericin B solution was performed. Finally, the globe was saved and there was no further recurrent infection. A cultured mycelial organism, which was hard to identify by biomorphology, was confirmed by PCR to be Pythium insidiosum. The zoospores were observed in water environments. The imaging characteristics of P. insidiosum in confocal microscopy are described herein.Conclusions:This is the first case of Pythium insidiosum keratitis reported in China. It can be misdiagnosed as fungal keratitis in the clinic. Improving the awareness of clinicians, promoting early diagnosis, and a multidisciplinary approach, especially early surgery, improve the prognosis.

Recent update in diagnosis and treatment of human pythiosis

“…Patients with Pythium keratitis usually present with typical clinical manifestations, including multiple, linear, tentacle-like infiltrates and dot-like or pinhead-shaped infiltrates, involving the subepithelial, anterior stromal, and midstromal layers in surrounding cornea and radiating in a reticular pattern from the central area of the lesion towards the limbus (Fig. 3) (Lekhanont et al, 2009;Lelievre et al, 2015;Bagga et al, 2018;Chatterjee & Agrawal, 2018;Agarwal et al, 2019;He et al, 2016;Thanathanee et al, 2013;Sharma et al, 2015;Agarwal et al, 2018). Radial keratoneuritis has been observed in some cases (Lekhanont et al, 2009;He et al, 2016).…”

“…3) (Lekhanont et al, 2009;Lelievre et al, 2015;Bagga et al, 2018;Chatterjee & Agrawal, 2018;Agarwal et al, 2019;He et al, 2016;Thanathanee et al, 2013;Sharma et al, 2015;Agarwal et al, 2018). Radial keratoneuritis has been observed in some cases (Lekhanont et al, 2009;He et al, 2016). Corneal lesions should be closely monitored, as the typical features of Pythium keratitis may develop during the course of the disease (Chatterjee & Agrawal, 2018).…”

“…An extensive and aggressive infiltration of P . insidiosum could result in corneal perforation, anterior chamber, limbal and scleral invasions, or endophthalmitis in a few days or weeks (Lekhanont et al, 2009;Lelievre et al, 2015;Rathi et al, 2018;Agarwal et al, 2019;Badenoch et al, 2001;He et al, 2016;Maeno et al, 2019;Ros Castellar et al, 2017;Thanathanee et al, 2013;Sharma et al, 2015;Agarwal et al, 2018).…”

“…P. insidiosum hyphae can be identified using IVCM in 95% of cultureor PCR-positive patients (Anutarapongpan et al, 2018). Pythium keratitis manifest as hyperreflective branching structures (vary in size; 1.5-7.5 µm in diameter and 90-400 µm in length), septate linear branching structures resembling fungal filaments, and irregular filaments arranged in a sinuous, various branching pattern, forming ''X'','' Y'', and'' S'' shapes as seen by IVCM (Lelievre et al, 2015;He et al, 2016;Tanhehco et al, 2011;Thanathanee et al, 2013). However, microbial characteristics captured by IVCM are non-specific and overlapped among Pythium, Aspergillus, and Fusarium keratitis (Anutarapongpan et al, 2018).…”

Clinical Outcomes of Radical Surgery and Antimicrobial Agents in Vascular Pythiosis: A Multicenter Prospective Study

“…The clinical presentations are classified into four groups: vascular, ocular, subcutaneous/cutaneous, and disseminated infection [ 2 ]. Human pythiosis has also been reported from the United States of America, Canada, Brazil, Frances, Israel, India, China, and Australia [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. In Thailand, vascular pythiosis is the most common form and it is associated with a mortality rate of 10–40%, depending on the rate of successful surgery [ 10 , 11 , 12 , 13 ].…”