Septic Pylephlebitis and Cavernous Transformation Presenting as Pyrexia of Unknown Origin: A Diagnostic Challenge

Acute cholangitis classically presents with fever, jaundice, and right upper quadrant pain, but atypical or subacute disease may present as pyrexia of unknown origin (PUO) and remain unrecognized until vascular complications develop. We report a 45-year-old man referred for weight loss, malaise, and suspected non-cirrhotic portal hypertension after upper gastrointestinal endoscopy showed esophageal varices despite a normal FibroScan. Detailed history revealed intermittent fever for 2 months. Laboratory evaluation demonstrated marked systemic inflammation, with leukocytosis, neutrophilia, ferritin 1095 ng/mL, and C-reactive protein > 200 mg/L, together with a cholestatic-hepatitic liver enzyme pattern and preserved liver synthetic function. Blood and urine cultures were negative. Initial ultrasonography showed bile duct dilatation without a definite obstructing lesion, delaying diagnosis. Subsequent magnetic resonance cholangiopancreatography and contrast-enhanced computed tomography demonstrated biliary abnormality with portal vein thrombosis and periportal collateralization, consistent with septic pylephlebitis, cavernous transformation, and portal biliopathy secondary to occult cholangitis. The patient was treated with intravenous broad-spectrum antibiotics and anticoagulation, with clinical improvement and partial portal vein recanalisation on follow-up ultrasonography at 3 months. This case highlights that occult cholangitis should be considered in patients with PUO and cholestatic liver biochemistry, even in the absence of classic biliary symptoms, and that early cross-sectional biliary imaging may allow timely recognition of pylephlebitis before chronic portal hypertensive and biliary sequelae become established.