Overview
Pythiosis is an emerging infectious disease caused by the aquatic oomycete Pythium insidiosum, presenting primarily as vascular and ocular infections in humans 1. It often affects farmers, particularly in Thailand, manifesting as nonhealing cutaneous ulcers or keratitis 2.Diagnosis
Clinical Presentation: Nonhealing ulcers, ocular infections, subcutaneous infections, and arteritis 2.
High Index of Suspicion: Especially in thalassemia patients with arterial insufficiency and those with unresponsive fungal keratitis/endophthalmitis 1.
Diagnostic Tests:
- Tissue Culture: Gold standard with zoospore induction 1.
- DNA-Based Methods: Should be performed concurrently with culture 1.
Difficulty: Distinguishing Pythium insidiosum from other molds 1.Management
First-Line Treatments:
- Surgery: Radical debridement, often required despite negative margins due to potential residual disease 1.
- Antifungal Agents: Specific drug classes and doses not detailed in abstracts 1.
Adjunctive Treatments:
- Immunotherapy: Recommended in combination with surgery and antifungals 1.
- Systemic Antifungal Therapy: Essential component alongside surgical intervention 2.Special Populations
Thalassemia Patients: Higher risk for arterial insufficiency and pythiosis 12.
Farmers: Particularly susceptible due to occupational exposure 2.Key Recommendations
Maintain a high index of suspicion for pythiosis in farmers and thalassemia patients with nonhealing ulcers or unresponsive fungal ocular infections (Evidence: Expert opinion) 12.
Combine radical surgical debridement with systemic antifungal therapy and immunotherapy for optimal management (Evidence: Moderate) 12.
Utilize both tissue culture with zoospore induction and DNA-based methods for accurate diagnosis (Evidence: Moderate) 1.References
1 Permpalung N, Worasilchai N, Chindamporn A. Human Pythiosis: Emergence of Fungal-Like Organism. Mycopathologia 2020. link
2 Prasertwitayakij N, Louthrenoo W, Kasitanon N, Thamprasert K, Vanittanakom N. Human pythiosis, a rare cause of arteritis: case report and literature review. Seminars in arthritis and rheumatism 2003. link