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Cholecystitis is inflammation of the gallbladder, a small pear-shaped organ in the upper right side of the abdomen just below the liver. In a healthy individual, the gallbladder stores bile produced by the liver to help the body digest fat. After a meal, particularly a high-fat meal, bile passes from the gallbladder through the cystic and common bile ducts and into the small intestine, where it helps metabolize fats. Cholecystitis generally results from obstruction of the cystic duct from gallstones (cholelithiasis) and is referred to as calculous cholecystitis, although approximately 10% of cases occur in the absence of stones (acalculous cholecystitis) (Gladden).
Cholecystitis is characterized initially by pain (biliary colic) in the upper right quadrant of the abdomen, which increases in intensity over 2 to 3 minutes and then levels off, persisting for 20 minutes or more. The pain may radiate from the abdomen to the back and/or shoulder. It generally occurs within an hour after meals and can last up to several hours. Nausea, vomiting, anorexia, and low-grade fever may also be noted. Episodes may come and go over a period of 2 to 3 days and are usually completely gone within a week.
Most cases (approximately 90% to 95%) of cholecystitis occur in individuals who have developed rock-like deposits (gallstones) in the gallbladder (Gladden), a condition called cholelithiasis. If a gallstone passes from the gallbladder into the cystic duct, blockage of the duct may cause distention of the gallbladder with decreased blood and lymphatic flow; this will trap bile in the gallbladder. The trapped bile irritates the walls of the gallbladder and creates an ideal environment for growth of infection-causing bacteria. Secondary bacterial infection occurs in up to 75% of those with acute cholecystitis, usually caused by Escherichia coli, klebsiella, or streptococcus organisms (Caddy).
Pressure from bile build-up also may result in rupture (perforation) of the gallbladder. As the immune system responds to irritation and/or infection, the gallbladder becomes inflamed, resulting in acute cholecystitis. This acute condition can become chronic with repeated flare-ups, especially in individuals who consume a diet high in fats, or who have a high level of lipids (fats) in the blood (hyperlipidemia), diabetes mellitus, or chronic alcoholism. Acute cholecystitis occasionally may occur in pregnancy accompanied by biliary colic, recurrent symptoms, and sometimes premature delivery. In chronic cholecystitis, the walls of the gallbladder gradually thicken, and the gallbladder eventually shrinks and no longer performs its function.
In some individuals, including pregnant women, those who have lost weight rapidly, or those who are nourished through a feeding tube (parenteral nutrition) or intravenously, gallbladder emptying is impaired, and bile may produce a thick, insoluble material known as gallbladder sludge which irritates gallbladder walls in much the same way as trapped bile does. Trauma to the body such as physical trauma (e.g., explosion or other accident), Salmonella poisoning, sepsis (systemic infection) and other infections, intravenous narcotic usage, or cardiac surgery can result in cholecystitis without the presence of gallstones (acalculous cholecystitis). This type of cholecystitis occurs in up to 10% of cholecystitis cases (Caddy; Gladden). It is serious and is associated with an increased risk of complications including death. Other causes include a growth (neoplasm) in the common bile duct, narrowing (stricture) of the common bile duct, or a loss of blood flow (ischemia) to the gallbladder wall. Ischemia is seen in a smaller number of cases occurring primarily in individuals with diabetes. Cholecystitis can also result if the gallbladder becomes twisted, although this is also uncommon.
While most individuals with gallstones (about 80%) remain asymptomatic; acute cholecystitis may develop in as many as one third of adults with gallstones (Caddy). Risk for developing cholecystitis is highest among individuals having a prior personal or family history of gallstones or cholecystectomy.
Risk: Factors that correspond to those for gallstone formation, including hyperlipidemia, high-carbohydrate diet (high glycemic load), obesity, diabetes mellitus, hemoglobinopathies and chronic alcohol use. The risk for developing cholecystitis increases with age (Gladden). Twice as many women as men are affected by this condition, and pregnancy or hormone use are observed risk factors. Certain populations including Native Americans and Hispanics are at greater risk (Gladden). Among individuals undergoing weight-loss surgery (bariatric surgery), 20% to 35% develop gallstones postoperatively (Caddy). Incidence and Prevalence: Cholelithiasis and cholecystitis are relatively common conditions. Approximately 10% to 20% of Americans have gallstones and one-third develop acute cholecystitis (Gladden). The incidence of cholelithiasis is high among Native American, Scandinavian, and Hispanic populations (Gladden). Incidence is higher among whites than blacks in the US (Gladden). |