Pythium Keratitis Leading to Fatal Cavernous Sinus Thrombophlebitis

Area of Science:

• Ophthalmology
• Medical Mycology
• Infectious Diseases

Background:

• Pythium insidiosum is an oomycete pathogen that can cause severe infections in humans, including keratitis.
• Ocular pythiosis is a rare but aggressive condition often mistaken for fungal keratitis.

Observation:

• A 70-year-old man developed severe keratitis after washing his hair with tap water.
• Initial corneal scrapings were misidentified as bacterial, delaying appropriate treatment.
• The patient progressed to develop proptosis, extraocular movement restriction, and ultimately cavernous sinus thrombophlebitis.

Findings:

• Microscopic examination and Polymerase Chain Reaction (PCR) confirmed Pythium insidiosum as the causative agent.
• Despite aggressive treatment including penetrating keratoplasty and exenteration, the infection led to cerebrovascular complications and death.
• The case highlights the diagnostic challenges and aggressive nature of Pythium insidiosum ocular infections.

Implications:

• Ocular pythiosis can have devastating systemic consequences, including potentially fatal cavernous sinus thrombophlebitis.
• A high index of suspicion for Pythium insidiosum is necessary in refractory keratitis cases, especially those initially suspected to be fungal.
• Prompt and radical surgical intervention, alongside appropriate antimicrobial therapy, is vital for improving patient outcomes.