Description

• Infection of the biliary tree due to partial or complete obstruction, most commonly due to gallstone migration into the common bile duct (CBD). The CBD may not be dilated if obstruction is partial. Increased pressure from partial obstruction may be the precipitant; these patients may have isolated alkaline phosphatase elevation.
• Presentation may be nonspecific, but classically:
  • Clinical triad of fever, jaundice, and right upper quadrant (RUQ) pain (Charcot triad); OR
  • Reynolds pentad of fever, jaundice, RUQ pain, mental status changes, and hypotension
• Severity may range from mild pain and low-grade fever to life threatening.
• Rarely, nonspecific constitutional complaints (malaise, isolated fever, mental status changes)
• When suspected, urgent intervention is needed, medically and/or surgically.
• 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 90% of cases. Any age, but more common in adults after age 40; incidence increases with age:
  • Rare in children (except in hemolytic disorders)
• More common: Hemolysis, women, elderly, Native Americans, Latinos, Asians, African Americans with sickle cell disease
• ~1–3% of patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) develop cholangitis.

• CBD stones discovered incidentally during evaluation of gallstones: 5–12%
• Acute cholangitis occurs in 6–9% of patients hospitalized with gallstone disease.
• Blood cultures positive with CBD stones: 20–30%

Risk Factors

• Cholelithiasis (see “Cholelithiasis, Risk Factors”)

  Pregnancy Considerations
  Pregnancy increases gallstone risk due to supersaturation of cholesterol in bile and decreased gallbladder motility.

• CBD stones
• Chronic bile duct inflammation due to sclerosing cholangitis, infection, and possibly hypothyroidism
• Periampullary malignancy
• Advanced age >70 years, usually >50
• Cirrhosis
• Ileal Crohn disease
• Hepatobiliary infections (Ascaris lumbricoides, Clonorchis sinensis, Schistosomiasis mansoni, Opisthorchis viverrini)
• Conditions that predispose to biliary stasis, including diabetes mellitus, obesity, pregnancy, rapid weight loss, prolonged fasting
• Biliary strictures or neoplasms, including masses that compress the duct; chronic pancreatitis with inflammatory CBD stricture
• Endoscopic or surgical manipulation; biliary stent
• Immunosuppression; rapid weight loss
• Medications such as octreotide and ceftriaxone as well as those containing estrogen

Genetics
Increased risk with positive family history of gallstones

General Prevention

• Moderate physical activity
• Avoid diet rich in saturated fatty acids
• Prophylactic ursodeoxycholic acid reduces bile lithogenicity in rapid weight loss and long-term somatostatin therapy or parenteral nutrition where increased risk of stasis exists.
• Long-term statin use reduces the cholesterol concentration of bile and is associated with a decreased risk of gallstone formation (not recommended for prevention).
• If cholecystectomy (CCY) is performed, ensure patency of biliary tree with intraoperative cholangiography; if operative view is not possible and CBD stone is suspected, endoscopic cholangiogram must be considered.
• Prophylactic antibiotics before ERCP (1)[A]

Pathophysiology

• Bacteria gain access to the biliary tree via retrograde ascent from the duodenum, trapped by a stone migrating from the gallbladder into CBD.
• Rarely, infection may enter from portal venous system, periportal lymphatics, or an eroding hepatic abscess or infected pancreatic fluid collection.
• Obstruction of biliary flow via choledocholithiasis (90%), infection, neoplasms, and/or strictures promotes bile stasis and spread of bacteria through the 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%).
• Pyogenic cholangitis in Asia is characterized by intrahepatic stones and recurrent attacks, most commonly due to parasitic infection.

Etiology

• Most common: Escherichia coli, Klebsiella pneumonia, and Enterococcus
• Also frequent: Bacteroides fragilis, Streptococcus faecalis, Enterobacter, and Pseudomonas
• Anaerobes, including Clostridium and Bacteroides species, are more frequent in polymicrobial infections, prior biliary-enteric surgery.
• Hospitalized patients are prone to methicillin-resistant Staphylococcus aureus, Pseudomonas species, and vancomycin-resistant Enterococcus.
• Cytomegalovirus, Cryptosporidium, Monoavium intracellulare, herpes simplex virus are common isolates in AIDS cholangiopathy (2)[B]. In AIDS, acute cholecystitis may be acalculous without visualized gallstones due to infection, inflammation, or ischemia of the gallbladder wall.

Commonly Associated Conditions

• Biliary pancreatitis
• Crohn disease
• AIDS
• Sepsis