Acute Cholangitis Workup

Procalcitonin may have potential as a useful biomarker for determining the need for emergency biliary drainage and intensive care in patients with acute cholangitis. ^[18] Shinya et al noted that significantly elevated procalcitonin levels were found in their cohort of patients with grade III inflammation based on the 2013 Tokyo guidelines versus those with grade I inflammation, as well as those with positive hemocultures compared to those with negative hemocultures. Moreover, procalcitonin levels were significantly increased in severe cases that were underestimated as grade I or II. ^[18]

Imaging studies are important to confirm the presence and cause of biliary obstruction and to rule out other conditions. ^[3] Ultrasonography and computed tomography (CT) scanning are the most commonly used first-line imaging modalities. Endoscopic retrograde cholangiography, magnetic resonance cholangiopancreatography, and endoscopic ultrasonography are commonly used for both diagnostic and therapeutic purposes. ^[3]

Laboratory studies include the following:

• CBC: Leukocytosis: In patients with cholangitis, 79% had a WBC greater than 10,000/mL, with a mean of 13.6. Septic patients may be leukopenic.

• Electrolyte panel with renal function may be performed.

• Calcium level is necessary to check if pancreatitis, which can lead to hypocalcemia, is a concern.

• Expect liver function test results to be consistent with cholestasis, hyperbilirubinemia (88-100%), and increased alkaline phosphatase level (78%).

• Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels are usually mildly elevated.

• Prothrombin time and activated partial thromboplastin time: Do not expect either to be elevated unless sepsis is associated with disseminated intravascular coagulation or underlying cirrhosis exists. A coagulation profile may be required if the patient needs operative intervention.

• C-reactive protein level and erythrocyte sedimentation rate are typically elevated. ^[8]

• Blood cultures (2 sets): Between 20% and 30% of blood cultures are positive. Many exhibit polymicrobial infections.

• Urinalysis result is usually normal.

• Blood type, screen, and crossmatch: With urgent operating room dispatch, patients need to have blood available.

• Lipase: Involvement of the lower common bile duct may cause pancreatitis and an elevated lipase level. One third of patients have a mildly elevated lipase level.

• Pancreatic enzyme elevations suggest that bile duct stones caused the cholangitis, with or without gallstone pancreatitis. ^[19]

• Biliary cultures (not performed in the ED): Send biliary cultures if the patient has biliary drainage by interventional radiology or endoscopy.

Ultrasonography is excellent for gallstones and cholecystitis. ^[20] It is highly sensitive and specific for examining the gallbladder and assessing bile duct dilatation (see the following image). However, it often misses stones in the distal bile duct. ^[21]

Acute Cholangitis. Sonogram of dilated intrahepatic ducts.

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Consider the following:

• Transabdominal ultrasonography is the initial imaging study of choice. ^[22]

• Ultrasonography can differentiate intrahepatic obstruction from extrahepatic obstruction and image dilated ducts.

• In one study of cholangitis, only 13% of common bile duct (CBD) stones were observed on ultrasonography, but dilated CBD was found in 64%.

• Advantages to sonography include the ability to be performed rapidly at the bedside by the ED physician, capacity to image other structures (eg, aorta, pancreas, liver), identification of complications (eg, perforation, empyema, abscess), and lack of radiation.

• Disadvantages to sonography include operator and patient dependence, cannot image the cystic duct, and decreased sensitivity for distal CBD stones.

• A normal sonogram does not rule out acute cholangitis.

Endoscopic retrograde cholangiopancreatography (ERCP) is both diagnostic and therapeutic and is considered the criterion standard for imaging the biliary system.

ERCP should be reserved for patients who may require therapeutic intervention. Patients with a high clinical suspicion for cholangitis should proceed directly to ERCP.

ERCP has a high success rate (98%) and is considered safer than surgical and percutaneous intervention.

Diagnostic use of ERCP carries a complication rate of approximately 1.38% and a mortality rate of 0.21%. The major complication rate of therapeutic ERCP is 5.4%, and it has a mortality rate of 0.49%. Complications include pancreatitis, bleeding, and perforation. ^[23] Post-ERCP cholecystitis is more frequent in patients who do not respond to initial antibiotic therapy compared to patients in whom initial antibiotic therapy is effective. ^[14]

Computed tomography (CT) scanning is adjunctive to and may replace ultrasonography. Spiral or helical CT improves imaging of the biliary tree. CT cholangiography uses a contrast agent that is taken up by the hepatocytes and secreted into the biliary system. This enhances the ability to visualize radiolucent stones and increases detection of other biliary pathology.

Dilated intrahepatic (see the image below) and extrahepatic ducts and inflammation of the biliary tree are imaged. Gallstones are poorly visualized with traditional CT scan.

Acute Cholangitis. CT scan of dilated intrahepatic bile ducts. Image courtesy of David Schwartz, MD, New York University Hospital.

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Advantages of CT include the following:

• Other pathologies that are causes or complications of cholangitis (eg, ampullary tumors, pericholecystic fluid, liver abscesses) can be imaged.

• Pathology that must be distinguished from cholangitis also can be observed (eg, right-sided diverticulitis, papillary necrosis, some evidence of pyelonephritis, mesenteric ischemia, ruptured appendix).

• Detection of biliary pathology with CT cholangiography approaches that of endoscopic retrograde cholangiopancreatography (ERCP).

Disadvantages of CT include poor imaging of gallstones, allergic reaction to contrast, exposure to ionizing radiation, and diminished ability to visualize the biliary tree with elevated serum bilirubin level.

Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive imaging modality that is increasingly being used in the diagnosis of biliary stones and other biliary pathology.

MRCP is accurate for detecting choledocholithiasis, neoplasms, strictures, and dilations within the biliary system.

Limitations of MRCP include the inability for invasive diagnostic tests such as bile sampling, cytologic testing, stone removal, or stenting. It has limited sensitivity for small stones (< 6 mm in diameter).

Absolute contraindications are the same as for a traditional MRI, which include the presence of a cardiac pacemaker, cerebral aneurysm clips, ocular or cochlear implants, and ocular foreign bodies. Relative contraindications include the presence of cardiac prosthetic valves, neurostimulators, metal prostheses, and penile implants.

The risk of MRCP during pregnancy is not known.

In general, abdominal films aid little in the diagnosis of acute cholangitis. Findings may include the following:

• An ileus may be observed.

• Between 10% and 30% of gallstones have a ring of calcium and, as a result, are radiopaque.

• Films may show air in the biliary tree after endoscopic manipulation or if the patient has emphysematous cholecystitis, cholangitis, or a cholecystic-enteric fistula.

• Air in the gallbladder wall indicates emphysematous cholecystitis.

Biliary scintigraphy (hepatic 2,6-dimethyliminodiacetic acid [HIDA] and diisopropyl iminodiacetic acid [DISIDA]) scans are functional studies of the gallbladder.

Obstruction of the common bile duct causes nonvisualization of the small intestine. A HIDA scan with complete biliary obstruction does not visualize the biliary tree.

Advantages include their ability to assess function and positive results may appear before the ducts are enlarged sonographically.

One disadvantage is that high bilirubin levels (>4.4) may decrease the sensitivity of the study. Recent eating or no food in 24 hours also may affect the study. In addition, anatomic imaging for other structures is lacking. The study takes several hours, so it is not recommended in critically ill or unstable patients.

ED physicians generally do not perform procedures for cholangitis (eg, endoscopic retrograde cholangiopancreatography [ERCP] and transhepatic decompression).

If an obstruction is observed, ERCP provides direct visualization and potential treatment. It is best performed after 72 hours of antibiotics or after resolution of fever.

In unstable patients, a reasonable option for decompression of the biliary tract is percutaneous transhepatic cholangiogram and biliary drain. The biliary ducts are observed, even when no ductal dilatation is present.