Abstract
Acute Suppurative Obstructive Cholangitis (AOSC) typically resolves post-ERCP. However, a 53-year-old male had persistent hyperbilirubinemia and leukocytosis (WBC 28.12×10(9)/L) along with marked eosinophilia (20.26×10(9)/L) despite standard antibiotic therapy. Systematic diagnosis ruled out residual calculi, Endoscopic Nasobiliary Drainage (ENBD) dysfunction, biliary neoplasms, and sclerosing cholangitis. A history of undercooked freshwater fish consumption and eosinophilia prompted suspicion of occult liver fluke infection, despite negative initial stool tests. Diagnostic treatment with albendazole resulted in a decrease in WBC and eosinophil counts; subsequent detection of liver flukes in ENBD fluid and positive liver fluke IgG confirmed the diagnosis. At 2-month follow-up, all markers normalized. This case highlights the diagnostic value of eosinophilia in guiding the identification of parasitic infections in refractory post-ERCP inflammation, and the utility of diagnostic therapy when direct evidence is lacking.