Ascending cholangitis or acute cholangitis (or sometimes cholangitis without a modifier - from Greek chol-, bile + ang-, vessel + itis-, inflammation) is an infection of the bile duct (cholangitis), usually caused by bacteria ascending from its junction with the duodenum (first part of the small intestine). It tends to occur if the bile duct is already partially obstructed by gallstones.Cholangitis can be life-threatening, and is regarded as a medical emergency. Characteristic symptoms include jaundice, fever, abdominal pain, and in severe cases, low blood pressure and confusion. Initial treatment is with intravenous fluids and antibiotics, but there is often an underlying problem (such as gallstones or narrowing in the bile duct) for which further tests and treatments may be necessary, usually in the form of endoscopy to relieve obstruction of the bile duct.