Porth's Essentials of Pathophysiology, 4e

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Disorders of Hepatobiliary and Exocrine Pancreas Function

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not always, have experienced previous episodes of biliary pain. The pain may appear with remarkable suddenness and constitute a surgical emergency. In the absence of medical attention, the attack usually subsides in 7 to 10 days and frequently within 24 hours. In persons who recover, recurrence is common. The onset of acalculous cholecystitis tends to be more insidious because the man- ifestations are obscured by the underlying conditions precipitating the attack. In the severely ill patient, early recognition is crucial because a delay in treatment can prove life-threatening. Persons with acute cholecystitis usually have an elevated white blood cell count and many have mild elevations in AST, ALT, ALP, and bilirubin. Chronic Cholecystitis Chronic cholecystitis results from repeated episodes of acute cholecystitis or chronic irritation of the gallblad- der by stones. 3,4 It is characterized by varying degrees of chronic inflammation. Gallstones almost always are present. Cholelithiasis with chronic cholecystitis may be associated with acute exacerbations of gallbladder inflammation, common duct stones, pancreatitis, and, rarely, carcinoma of the gallbladder. The manifestations of chronic cholecystitis are more vague than those of acute cholecystitis. There may be intolerance to fatty foods, belching, and other indications of discomfort. Often, there are episodes of colicky pain with obstruction of biliary flow caused by gallstones. The gallbladder, which in chronic cholecystitis usually contains stones, may be enlarged, shrunken, or of normal size. Diagnosis andTreatment of Gallbladder Disease The methods used to diagnose gallbladder disease include ultrasonography, cholescintigraphy (nuclear scanning), and CT scans. 43–45 Ultrasonography is widely used in diagnosing gallbladder disease and has largely replaced the oral cholecystogram in most medical centers. It can detect stones as small as 1 to 2 cm, and its overall accu- racy in detecting gallbladder disease is high. In addition to stones, ultrasonography can detect wall thickening, which indicates inflammation. It also can rule out other causes of right upper quadrant pain such as tumors. Cholescintigraphy, also called a gallbladder scan, relies on the ability of the liver to extract a rapidly injected radionuclide, technetium-99m, bound to one of several iminodiacetic acids, that is excreted into the bile ducts. Serial scanning images are obtained within several min- utes of the injection of the tracer and every 10 to 15 min- utes during the next hour. The gallbladder scan is highly accurate in detecting acute cholecystitis. Although CT is not as accurate as ultrasonography in detecting gall- stones, it can show thickening of the gallbladder wall or pericholecystic fluid associated with acute cholecystitis. Gallbladder disease usually is treated by removing the gallbladder. The gallbladder stores and concen- trates bile, and its removal usually does not interfere with digestion. Laparoscopic cholecystectomy has become the treatment of choice for symptomatic gall- bladder disease. 45 The procedure involves insertion of a

(85% to 90%) are associated with the presence of gall- stones (calculous cholecystitis). 3,4,44,45 The remaining cases (acalculous cholecystitis) are associated with sep- sis, severe trauma, or infection of the gallbladder. Acute acalculous cholecystitis, which involves ischemic rather than inflammatory changes associated with stones, can rapidly progress to gangrene and perforation. 44 Acute calculous cholecystitis occurs when a stone becomes impacted in the cystic duct and inflammation develops behind the obstruction. It has been theorized that obstruction of the cystic duct leads to the release of mucosal phospholipase from the epithelium of the gall- bladder. These lipases, in turn, lead to disruption of the normal glycoprotein mucous layer, exposing the muco- sal epithelium to the destructive action of concentrated bile salts. 3,4 Acute acalculous cholecystitis is thought to result from ischemia. The cystic artery is an end artery with essentially no collateral circulation. 3 Contributing factors may include inflammation and edema of the gall- bladder wall, stasis of bile, and conditions that lead to cystic duct obstruction in the absence of frank stone for- mation. Risk factors for acute acalculous cholecystitis include sepsis with hypotension and multisystem organ failure, immunosuppression, major trauma and burns, diabetes mellitus, and infections. 3,44 Persons with acute cholecystitis usually experience an sudden onset of upper right quadrant or epigastric pain, frequently associated with mild fever, anorexia, nausea, vomiting. 43–45 Whereas in biliary colic the cystic duct obstruction is transient, in acute cholecystitis it is per- sistent. Persons with calculous cholecystitis usually, but FIGURE 30-16. Cholesterol gallstones.The gallbladder has been opened to reveal numerous yellow cholesterol gallstones. (From Herrine SK, Navarro VJ, Rubin R.The liver and biliary system. In: Rubin R, Strayer DS, eds. Rubin’s Pathology: Clinicopathologic Foundations of Medicine. 6th ed. Philadelphia, PA: Wolters Kluwer Health | Lippincott Williams & Wilkins; 2012:732.)