Chapter 3-6: Acute Cholecystitis

TEXTBOOK PRESENTATION

Typical symptoms of acute cholecystitis include persistent RUQ or epigastric pain, fever, nausea, and vomiting.

DISEASE HIGHLIGHTS

1. Secondary to prolonged cystic duct obstruction (> 4–6 hours)

2. Persistent obstruction results in increasing gallbladder inflammation and pain. Necrosis, infection, and gangrene may occur.

3. Jaundice and marked elevation of liver enzymes are seen only if the stone migrates into the CBD and causes obstruction.

EVIDENCE-BASED DIAGNOSIS

1. No clinical finding is sufficiently sensitive to rule out cholecystitis.

   1. Fever: (sensitivity, 29–44%; specificity, 37–83%)

   2. Marked RUQ tenderness (sensitivity, 60–98%; specificity, 1–97%; LR+, 2.7; LR–, 0.4)

   3. Murphy sign

      1. Sensitivity, 65%; specificity, 87%

      2. LR+, 5.0; LR−, 0.4

2. Laboratory findings

   1. Leukocytosis (> 10,000/mcL) is present in 52–63% of patients.

   2. Cholecystitis does not typically cause significant increases in lipase or liver biochemical tests. Such findings suggest complications of pancreatitis and choledocholithiasis.

3. Ultrasound

   1. Test of choice due to speed, cost, ability to image adjacent organs and lack of radiation.

   2. Sensitivity, 81%; specificity, 83%; LR+, 4.8; LR−, 0.23

   3. Cholelithiasis is usually present (84–99%) but is not in and of itself diagnostic of acute cholecystitis.

   4. Additional findings that suggest acute cholecystitis include gallstones with gallbladder wall thickening, pericholecystic fluid, sonographic Murphy sign, or gallbladder enlargement > 5 cm. However, more specific findings may be less sensitive (27–38%).

   5. If ultrasound is normal, and clinical suspicion is high, consider HIDA (see below).

4. Bedside ultrasound by trained nonradiologists

   1. Used with increasing frequency in emergency departments

   2. One study reported good accuracy when performed by emergency department physicians with 5 hours of training; sensitivity, 91%; specificity, 66%; LR+, 2.7; LR–, 0.14.

   3. Abnormal results should be confirmed with formal ultrasonography.

   4. Normal results are probably adequate to rule out cholecystitis in patients with low pretest probabilities but not in those for whom there is a higher suspicion of acute cholecystitis.

5. Cholescintigraphy (HIDA) scans

   1. Radioisotope is excreted by the liver into the biliary system. In normal patients, the gallbladder concentrates the isotope and is visualized. Visualization essentially excludes acute cholecystitis.

   2. Nonvisualization of the gallbladder suggests cystic duct obstruction and is highly specific for acute cholecystitis (96% sensitive, 90% specific).

   3. Nonvisualization can also be seen in prolonged fasting, hepatitis, alcohol abuse, and prior biliary sphincterotomy.

   4. Useful when the pretest probability is high, due to persistent pain, and the ultrasound is nondiagnostic (ie, the ultrasound demonstrates stones within the gallbladder but no clear evidence of cholecystitis is seen, eg, no stones within the cystic duct nor evidence of gallbladder wall thickening or pericholecystic fluid).

6. A diagnostic algorithm to the approach of suspected gallstone disease is shown in Figure 3-4.

TREATMENT

Patients with acute cholecystitis should be admitted, administered parenteral antibiotics, and undergo cholecystectomy. The timing of surgery depends on the severity of disease and medical risk assessment.