Choledocholithiasis and Cholangitis

Choledocholithiasis is the presence of stones in bile ducts; the stones can form in the gallbladder or in the ducts themselves. These stones cause biliary colic, biliary obstruction, gallstone pancreatitis, or cholangitis (bile duct infection and inflammation). Cholangitis, in turn, can lead to strictures, stasis, and choledocholithiasis. Diagnosis usually requires visualization by magnetic resonance cholangiopancreatography or endoscopic retrograde cholangiopancreatography. Early endoscopic or surgical decompression is indicated.

(See also Overview of Biliary Function.)

Stones may be described as

• Primary stones (usually brown pigment stones), which form in the bile ducts

• Secondary stones (usually cholesterol), which form in the gallbladder but migrate to the bile ducts

• Residual stones, which are missed at the time of cholecystectomy (evident < 3 years later)

• Recurrent stones, which develop in the ducts > 3 years after surgery

In industrialized countries, > 85% of common duct stones are secondary (1); affected patients have additional stones located in the gallbladder. Up to 10% of patients with symptomatic gallstones also have associated common bile duct stones (1). After cholecystectomy, brown pigment stones may result from stasis (eg, due to a postoperative stricture) and the subsequent infection. The proportion of ductal stones that are pigmented increases with time after cholecystectomy.

Bile duct stones may pass into the duodenum asymptomatically. Biliary colic occurs when the ducts become partially obstructed. More complete obstruction causes duct dilation, jaundice and, eventually, cholangitis (a bacterial infection). Stones that obstruct the ampulla of Vater can cause gallstone pancreatitis. Some patients (usually those who are older) present with biliary obstruction due to stones that have caused no symptoms previously.

In acute cholangitis, bile duct obstruction allows bacteria to ascend from the duodenum. Most (85%) cases (1) result from common bile duct stones, but bile duct obstruction can result from tumors or other conditions (see table Causes of Bile Duct Obstruction). Common infecting organisms include gram-negative bacteria (eg, Escherichia coli, Klebsiella species, Enterobacter species); less common are gram-positive bacteria (eg, Enterococcus species) and mixed anaerobes (eg, Bacteroides species, Clostridia species). Symptoms include abdominal pain, jaundice, and fever or chills (Charcot triad). The abdomen is tender, and often the liver is tender and enlarged (possibly containing abscesses). Confusion and hypotension, abdominal pain, jaundice, and fever or chills (Reynolds' pentad) predict about a 50% mortality rate and high morbidity.

Recurrent pyogenic cholangitis (Oriental cholangiohepatitis, hepatolithiasis) is characterized by intrahepatic brown pigment stone formation. This disorder occurs in Southeast Asia. It consists of sludge and bacterial debris in the bile ducts. Undernutrition and parasitic infestation (eg, Clonorchis sinensis, Opisthorchis viverrini) increase susceptibility. Parasitic infestation can cause obstructive jaundice with intrahepatic ductal inflammation, proximal stasis, stone formation, and cholangitis. Repeating cycles of obstruction, infection, and inflammation lead to bile duct strictures and biliary cirrhosis. The extrahepatic ducts tend to be dilated, but the intrahepatic ducts appear straight because of periductal fibrosis.

In AIDS-related cholangiopathy or cholangitis, direct cholangiography may show abnormalities similar to those in primary sclerosing cholangitis (PSC) or papillary stenosis (ie, multiple strictures and dilations involving the intrahepatic and extrahepatic bile ducts). Etiology is probably infection, most likely with cytomegalovirus, Cryptosporidium species, or microsporidia.