Biliary Tract Disease

Noting that no single combination of findings can be relied on to identify all patients with acute cholecystitis at the time of presentation, the author discusses the keys to diagnostic accuracy and successful treatment in biliary tract disease.

By David A. Townes, MD, MPH, FACEP

What are the different types of biliary tract disease?

In the United States, most cases of biliary tract disease result from complications of gallstones. The pathophysiology of biliary tract disease may be thought of as a continuum similar to appendicitis, including obstruction, local inflammation, distension, local infection, perforation, and systemic illness. However, it is not uncommon for a stage to be skipped or two stages reversed in this continuum. Patients may be systemically ill prior to perforation, for example.

Cholelithiasis is the presence of calculi in the gallbladder. Cholecystitis results when there is obstruction of the cystic duct, causing distension and inflammation of the gallbladder. Approximately 90% of cases of cholecystitis are associated with calculi. The remaining 10% are acalculous. Obstruction of the cystic duct with distension and inflammation of the gallbladder and bacterial infection results in cholangitis.

Another common form of biliary tract disease is bile leak, most often seen approximately 5 to 10 days after surgery. It is more likely to occur after laparoscopic surgery than after open cholecystectomy.

Malignancies of the biliary tract are uncommon. Carcinoma of the gallbladder is the most prevalent, accounting for 5% of all malignancies at autopsy. It is most common in women over age 50. Other types of biliary tract malignancy include carcinoma of the extrahepatic bile ducts, which is seen more often in men, and carcinoma of Vater's ampulla, which occurs more often in the elderly.
 

How common is biliary tract disease?

Biliary tract disease is very common. Between 10% and 20% of Americans have gallstones, and approximately 33% of them will develop acute cholecystitis at some point in their lives, resulting in more than 500,000 operations annually at a cost of $5 billion.
 

What are the risk factors for biliary tract disease?

Risk factors for biliary tract disease include aging, obesity, rapid weight loss, cystic fibrosis, parity, certain medications (such as clofibrate and oral contraceptives), familial tendency, and certain diseases (such as sickle cell anemia). Being female is also a risk factor; women are affected twice as often as men.
 

What are the common signs and symptoms and typical laboratory findings in biliary tract disease?

The most common presenting symptom of biliary tract disease is abdominal pain. The term biliary colic is somewhat misleading. While there may be a history of pain that was initially colicky in nature, the pain is often constant by the time the patient presents in the acute care setting. Due to the innervation of the biliary tract, the pain may be diffuse or it may be located in the epigastric area, the right upper quadrant, the shoulder, or the back. Other symptoms include fever, anorexia, nausea, and vomiting. Charcot described a triad of fever, jaundice, and right upper quadrant pain in cholangitis. Reynold's pentad adds shock and altered mental status.

Signs of biliary tract disease include abdominal tenderness, a palpable gallbladder, and Murphy's sign (interruption of deep inspiration with firm palpation beneath the right costal arch, below the hepatic margin). Key laboratory findings include leukocytosis, elevated hepatic aminotransferases, mild hyperbilirubinemia, and elevated serum amylase.

Several studies have examined the frequency, sensitivity, and specificity of signs and symptoms and laboratory findings in biliary tract disease to aid clinicians in establishing the correct diagnosis. The results demonstrate that no single combination of clinical or laboratory findings identifies all patients with acute cholecystitis at the time of presentation. A significant number of patients with cholecystitis had no fever, normal hepatic aminotransferases, and a normal white blood cell count. Murphy's sign was identified as having the highest sensitivity and positive predictive value. These results suggest that any patient suspected of having biliary tract disease should undergo an imaging study to help establish the diagnosis.
 

What is the differential diagnosis for patients with suspected biliary tract disease?

The differential diagnosis of abdominal pain, the most common presenting symptom of biliary tract disease in the emergency department, is very broad. Besides biliary tract disease, the differential may include peptic ulcer disease, gastritis, pancreatitis, renal colic, appendicitis, pneumonia, hiatal hernia, and cardiac disease. In certain cases, it may be difficult to distinguish between these entities without laboratory or imaging studies.
 

What are the options for imaging the biliary tract?

Options for imaging the biliary tract include plain radiographs, ultrasound, nuclear scintigraphy (HIDA scan), computed tomography (CT), and magnetic resonance imaging. Only 10% to 15% of gallstones can be visualized on plain radiographs; also, these x-rays offer no information about the function of the gallbladder or any structural abnormalities. Therefore, they should not be used as a primary tool for diagnosing biliary tract disease.

Far superior to plain radiographs is ultrasound. It is a test that reveals structure, providing valuable information about the presence of gallstones, pericholecystic fluid, gallbladder wall thickening, and biliary sludge, as well as distension of the gallbladder or common hepatic duct. Other advantages include ready availability, portability, and relative ease of use, and the fact that it does not involve use of a contrast agent or radiation. In many situations, the physician can perform ultrasound right at the bedside. Eliciting Murphy's sign with the ultrasound probe while visualizing the gallbladder is useful in establishing the diagnosis of biliary tract disease.

Unlike ultrasound, nuclear scintigraphy is a test of function rather than structure. It is generally comparable or superior to ultrasound in sensitivity and specificity. The patient is injected with technetium-99m, which binds to acids that are excreted into the bile ducts. In a person without biliary tract disease, the common bile ducts, small bowel, and gallbladder can be visualized. In a person with biliary obstruction, the common bile ducts and small bowel can be visualized but not the gallbladder.

Like ultrasound, a CT scan provides structural information about the gallbladder and the surrounding anatomy. While it does require use of a contrast agent and radiation, a CT scan may identify other conditions that can cause the patient's signs and symptoms. It has been suggested that in certain cases CT provides better visualization of distal common bile duct stones than ultrasound.

The choice of imaging study depends on the individual clinician, situation, and institution. Generally, nuclear scintigraphy and ultrasound are the imaging studies of choice for the patient suspected of having biliary tract disease in the acute care setting. The advantage of nuclear scintigraphy is its high sensitivity; the advantages of ultrasound are its availability and the fact that it is easy to use.
 

How should the pain of biliary colic be managed?

Common medications used to manage the pain of biliary colic include narcotics, nonsteroidal anti-inflammatory drugs, atropine, and dicyclomine. Studies have demonstrated comparable efficacy of narcotics and ketorolac in treating patients with biliary tract disease. Dicyclomine appears to be effective as well. Atropine has been shown to be no better than placebo.
 

What is the role of antibiotics in biliary tract disease?

The role of antibiotics in acute cholecystitis has not been clearly established. Patients with cholangitis, however, do require antibiotics (see box for choices). Due to the lack of an endothelial lining between the canaliculi and the capillaries in the liver, these patients are at high risk for bacteremia.

About 50% of patients with cholangitis will have positive blood cultures. Of these cultures, 80% will grow a single organism and 20% will grow two pathogens. Three or more organisms are rare in biliary tract disease.

Antibiotics should be directed at the most common organisms—namely, Escherichia coli followed by Klebsiella. Other likely pathogens include Bacteroides, Enterococcus, Pseudomonas, Clostridium, and anaerobic bacteria.
 

What is the appropriate disposition for a patient with biliary tract disease?

Disposition of the patient with biliary tract disease will depend on the diagnosis, the severity of the disease, and the individual patient. In general, patients with acute cholecystitis may be discharged home if they are stable and tolerating oral fluids well and have adequate pain control. It is also appropriate to admit these patients for further evaluation and treatment, including cholecystectomy or endoscopic retrograde cholangiopancreatography.

Patients with cholangitis should be admitted to the hospital and treated with intravenous fluids and intravenous antibiotics. Definitive treatment will depend on response to the initial therapy. A patient with a bile leak may require percutaneous or endoscopic drainage.

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