Description

• Acute infection and inflammation due to partial or complete obstruction of the biliary tree, most commonly by gallstones migrating into the common bile duct (CBD); also by endoscopic retrograde cholangiopancreatography (ERCP), tumor, parasitic disease, and stricture
• Primary choledocholithiasis (formation of stones in the CBD) is uncommon; occurs with bile stasis (e.g., cystic fibrosis, distal biliary stricture)
• Must distinguish from primary sclerosing cholangitis (PSC), a chronic progressive disorder of unknown etiology characterized by inflammation, fibrosis, and strictures with intra- and/or extrahepatic bile ducts
• Severity ranges from mild pain and low-grade fever to life-threatening sepsis.
• When suspected, urgent intervention is needed.
• System(s) affected: GI tract, hepatobiliary, other systems via hematogenous spread

Epidemiology

Parallels the prevalence of gallstones; stones migrating into the CBD are associated with up to 70% of cases. Median age of presentation is between 50 and 60 years; incidence increases with age.

• Stones more common in individuals of Northern European, Hispanic, and Native American descent
• Rare in children (except in hemolytic disorders such as sickle cell disease)

Prevalence

• CBD stones are discovered incidentally in 5–20% of patients undergoing routine evaluation for gallstones.
• Acute cholangitis occurs in 6–9% of patients hospitalized with gallstone disease.
• No gender differences have been reported.
• Patients with CBD stones have positive blood cultures in 20–30% of cases.

Etiology and Pathophysiology

• Obstruction of biliary flow by stones (90% of cases), neoplasms, or strictures promotes bile stasis and spread of bacteria from biliary tree into hepatic ducts.
• Increased intraluminal pressure decreases intrabiliary IgA secretion; disrupts hepatocellular tight junctions; and pushes bacteria into hepatic veins, biliary canaliculi, and perihepatic lymphatics, leading to bacteremia (25–40%). Bacteria gain access to the biliary tree via retrograde ascent from the duodenum.
• Rarely, infection enters from portal venous system, periportal lymphatics, an eroding hepatic abscess, or infected pancreatic fluid collection.
• The CBD may not be dilated if obstruction is partial, in which case an isolated alkaline phosphatase elevation is sometimes present.
• Pyogenic cholangitis in Asia is most commonly due to parasitic infection (Clonorchis sinensis, Opisthorchis viverrini, Ascaris lumbricoides, Schistosoma mansoni) and is characterized by intrahepatic stones and recurrent attacks.
• Most common bacterial organisms: Escherichia coli, Klebsiella pneumonia, and Enterococcus (1)[A]
• Others: Bacteroides fragilis, Streptococcus faecalis, Enterobacter, and Pseudomonas
• Anaerobes, including Clostridium and Bacteroides, are more frequent in polymicrobial infections and patients with prior biliary-enteric surgery.
• With biliary endoprosthesis, Pseudomonas and enterococcal species more common
• Hospitalized patients are prone to methicillin-resistant Staphylococcus aureus, Pseudomonas species, and vancomycin-resistant Enterococcus.
• Cytomegalovirus, Cryptosporidium, Mycobacterium avium-intracellulare, and herpes simplex virus are common in HIV-related cholangiopathy. In HIV patients, acute cholecystitis may be acalculous due to infection, inflammation, or gallbladder wall ischemia.

Genetics
Increased risk with family history of gallstones

Risk Factors

• Cholelithiasis, CBD stones
• Chronic bile duct inflammation due to sclerosing cholangitis, infection, and possibly hypothyroidism
• Periampullary malignancy
• Advanced age >70 years, usually >50 years old
• Cirrhosis
• Crohn disease
• Hepatobiliary infections
• Conditions predisposing to biliary stasis (diabetes mellitus, obesity, pregnancy, rapid weight loss, prolonged fasting)
• Hemolytic syndromes or biliary anomalies (children)
• Roux-en-Y bypass surgery
• Biliary strictures or neoplasms, including masses that compress the duct; chronic pancreatitis with inflammatory CBD stricture
• Endoscopic or surgical manipulation; biliary stent occurs in 10% postbiliary tract reconstruction.
• Immunosuppression
• Medications: octreotide, ceftriaxone, estrogen
• HIV or AIDS

Pregnancy Considerations
Gallstone risk increases during pregnancy due to biliary cholesterol supersaturation and decreased GB motility.

General Prevention

• Adequate physical activity
• Avoid foods rich in saturated fats.
• In patients with increased risk of biliary stasis, weight loss, long-term somatostatin therapy or parenteral nutrition, and use of ursodeoxycholic acid reduce lithogenicity.
• Long-term statin use reduces biliary cholesterol concentration and lowers risk of gallstone formation (not recommended for routine prevention).
• Ensure patency of biliary tree with intraoperative cholangiography (IOC) at time of cholecystectomy; if operative view is not possible and CBD stone is suspected, endoscopic cholangiogram is recommended.
• Prophylactic antibiotics before ERCP

Commonly Associated Conditions

• Pancreatitis, acute cholecystitis
• Crohn disease
• HIV/AIDS
• Sepsis