Cholecystitis
Laboratory Studies
Although laboratory criteria are not reliable in identifying all patients with cholecystitis, the following findings may be useful in arriving at the diagnosis:
Full Blood Count
Leukocytosis with a left shift may be observed in cholecystitis.
Liver Function Test
Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels are used to evaluate the presence of hepatitis and may be elevated in cholecystitis or with common bile duct obstruction.
Bilirubin and alkaline phosphatase assays are used to evaluate evidence of common duct obstruction.
An elevated alkaline phosphatase level is observed in 25% of patients with cholecystitis
Amylase levels
Amylase/lipase assays are used to evaluate the presence of pancreatitis. Amylase may also be elevated mildly in cholecystitis..
Urinalysis is used to rule out pyelonephritis and renal calculi.
All females of childbearing age should have pregnancy testing.
Imaging Studies
Radiography (without contrast)
Gallstones may be visualized in 10-15% of cases. This finding only indicates cholelithiasis, with or without active cholecystitis.
Subdiaphragmatic free air cannot originate in the biliary tract, and, if present, it indicates another disease process.
Gas limited to the gallbladder wall or lumen represents emphysematous cholecystitis, usually because of gas-forming bacteria, such as Escherichia coli and clostridial and anaerobic streptococci species. Emphysematous cholecystitis is associated with an increased mortality rate and occurs most commonly in males with diabetes and with acalculous cholecystitis.
A diffusely calcified gallbladder (ie, porcelainized) most commonly is associated with carcinoma, although one retrospective study by Towfigh found no association between partial calcification of the gallbladder and carcinoma.
Other findings may include renal calculi, intestinal obstruction, or pneumonia.
Ultrasonography
Ultrasonography provides greater than 95% sensitivity and specificity for the diagnosis of gallstones more than 2 mm in diameter. Ultrasonography is 90-95% sensitive for cholecystitis and is 78-80% specific. Ultrasonographic findings that are suggestive of acute cholecystitis include the following: pericholecystic fluid, gallbladder wall thickening greater than 4 mm, and sonographic Murphy sign. The presence of gallstones also helps to confirm the diagnosis.
Ultrasonography is performed best following a fast of at least 8 hours because gallstones are visualized best in a distended bile-filled gallbladder.
Hepatobiliary scintigraphy (hepatoiminodiacetic acid [HIDA]/diisopropyl iminodiacetic acid [DISIDA])
HBS has been found to be up to 95% accurate in diagnosing acute cholecystitis.If the gallbladder is not visualized, intravenous morphine administration can improve the accuracy of HBS by increasing resistance to flow through the sphincter of Oddi, resulting in filling of the gallbladder if the cystic duct is patent. The addition of morphine also reduces the number of false-positive scan results observed in patients who are critically ill and immobilized with viscous bile.
CT scan and MRI
The sensitivity and specificity of CT scan and MRI for predicting acute cholecystitis have been reported to be greater than 95%.7 Spiral CT scan and MRI (unlike endoscopic retrograde cholangiopancreatography [ERCP]) have the advantage of being noninvasive, but they have no therapeutic potential and are most appropriate in cases where stones are unlikely.
Findings suggestive of cholecystitis include wall thickening (>4 mm), pericholecystic fluid, subserosal edema (in the absence of ascites), intramural gas, and sloughed mucosa.
CT scan and MRI are also useful for viewing surrounding structures if the diagnosis is uncertain.
Cholangytis
Laboratory Studies
Complete blood count
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.
Liver Function Test
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.3
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 CBD 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.6
Biliary cultures (not performed in the ED): Send biliary cultures if the patient has biliary drainage by interventional radiology or endoscopy.
Imaging Studies
Imaging studies are important to confirm the presence and cause of biliary obstruction and to rule out other conditions. Ultrasonography and CT scanning are the most commonly used first-line imaging modalities.
Ultrasonography is excellent for gallstones and cholecystitis. It is highly sensitive and specific for examining the gallbladder and assessing bile duct dilatation. However, it often misses stones in the distal bile duct.7
Transabdominal ultrasonography is the initial imaging study of choice.
Ultrasonography can differentiate intrahepatic obstruction from extrahepatic obstruction and image dilated ducts.
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.
CT 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 and extrahepatic ducts and inflammation of the biliary tree are imaged.
Gallstones are poorly visualized with traditional CT scan.
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 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 name="0721">
Biliary scintigraphy (hepatic 2,6-dimethyliminodiacetic acid [HIDA] and diisopropyl iminodiacetic acid [DISIDA])
HIDA and DISIDA scans are functional studies of the gallbladder.
Obstruction of the CBD causes nonvisualization of the small intestine. A HIDA scan with complete biliary obstruction does not visualize the biliary tree.
Advantages include its 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.
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