Acute cholangitis is a clinical diagnosis. On ultrasound examination, the hallmark finding is thickened walls of the biliary ducts although this is non-specific. However, it is essential to identify biliary obstruction by stones (choledocholithiasis) and pus may also be identified as debris material within the common bile duct if present. In our case, clinical and laboratory evaluation confirmed ascending cholangitis, and repeated abdominal ultrasound examinations were requested after admission due to slowly responding high-grade fever.