Clinical profile, risk factors and outcome of medical, surgical and adjunct interventions in patients with Pythium insidiosum keratitis

Abstract

The currently available and recommended treatment for Pythium keratitis is surgical by means of a TPK and in worse cases evisceration. In our study, MM/MA measures showed no benefit with recurrence or worsening of infection requiring resurgery. Almost 50% of TPKs had a recurrence requiring resurgery. However, adjunctive procedures during TPK appear to have additional benefit with low risk of recurrence and could be included as routine care.

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).…”

“…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).…”

“…However, in eyes with very large or peripheral lesions extending up to the limbus, the outcome of therapeutic penetrating keratoplasty may be poor with a high risk of recurrence, because the surgical margin may not be free of infection. Adjunct therapy is therefore recommended in such cases to reduce the risk of recurrence (Agarwal et al, 2019;Agarwal et al, 2018). Application of single freeze-thaw cryotherapy on the host at the graft-host junction or at the limbus using 2 mm-tip retinal cryoprobe for 7-8 s has been used successfully to prevent recurrence (Agarwal et al, 2018).…”

“…The percentage of success and failure in smaller lesions (≤ 6 mm) was approximately equal and there was 100% failure in eyes with larger lesions (>6 mm) (Bagga et al, 2018). Furthermore, all patients in another series failed to respond and/or worsened with the triple regimen (Agarwal et al, 2019). Additional clinical trials are needed to investigate the true efficacy of these antibiotics, which have a common mechanism of action -inhibition of protein synthesis.…”

An initial survey of 150 horses from Thailand for anti-Pythium insidiosum antibodies

“…Data on the epidemiology of pythiosis is limited. Since the rst case in 1985, human pythiosis has been increasingly reported from all over Thailand [2,10,[13][14][15][16][17][18][19], where P. insidiosum is ubiquitous in the environment [3,4]. A seroprevalence study estimated that ~32,000 Thai people have been exposed to the pathogen [20].…”