Introduction

• Cause:Pythium insidiosum(formerly known asHyphomyces destruens,Pythium destruens,Pythium gracile) Pythium insidiosum.
• Signs: cutaneous and gastrointestinal signs.
• Diagnosis: serology, PCR assay, histopathology.
• Treatment: surgical excision, itraconazole Itraconazole with or without terbinafine Terbinafine.
• Prognosis: poor.

Pathogenesis

Etiology

• Pythium insidiosuman oomycete.
• Oomycetes are soil or water saprophytes.
• They are not true fungi.
• They produce motile flagellate zoospores, which are the infective stage.
• Their plasma membranes lack sterols, which is the site of activity of many antifungal drugs.

Predisposing factors

General

• Residing or traveling in an area where the organism is endemic.
• Contact with warm, stagnant water containing the infective stage.

Specific

• Seasonal occurrence, with most cases diagnosed between August and December (in the United States).
• Corticosteroid administration results in rapid dissemination of the disease.

Pathophysiology

• The organism may gain entrance to the body through breaks in the skin or by invading the gastrointestinal mucosa following ingestion.
• Gastrointestinal disease is the primary clinical manifestation.
• The organism has a predilection for the stomach, duodenum and ileum, causing an infiltrative granulomatous gastroenteritis Enteritis: granulomatous.
• Isolated masses may develop within the gastrointestinal tract.
• Cutaneous lesions begin as focal nodules that rapidly enlarge and become destructive to near by tissues.
• Necrosis of the skin and subcutaneous tissues may result.
• Large, spongioform lesions with multiple draining tracts are common.
• Some lesions involve the entire circumference of the affected limb.
• Cutaneous lesions are not often accompanied by gastrointestinal infection.

Timecourse

• Incubation poorly defined.
• Duration is weeks to months.

Diagnosis

Treatment

Prevention

Outcomes