Atlas of pathophysiology, 2 Edition

Part II - Disorders

Gastrointestinal Disorders

Cholecystitis

Cholecystitis—acute or chronic inflammation causing painful distention of the gallbladder—is usually associated with a gallstone impacted in the cystic duct. Cholecystitis accounts for 10% to 25% of all gallbladder surgery. The acute form is most common among middle-aged women; the chronic form, among elderly people. The prognosis is good with treatment.

Causes

·         Gallstones (the most common cause)

·         Poor or absent blood flow to the gallbladder

·         Abnormal metabolism of cholesterol and bile salts

Pathophysiology

In acute cholecystitis, inflammation of the gallbladder wall usually develops after a gallstone lodges in the cystic duct. Gallstones typically develop when metabolism of cholesterol and bile salts is abnormal. The liver usually makes bile continuously, and the gallbladder stores it until it's needed to help digest fat. Changes in the composition of bile may cause gallstones to form.

When gallstones block bile flow, the gallbladder becomes inflamed and distended. Growth of bacteria, usually Escherichia coli, may contribute to the inflammation and abscess formation or empyema.

Edema of the gallbladder (and sometimes the cystic duct) obstructs flow of bile, which chemically irritates the gallbladder. Cells in the gallbladder wall may become oxygen starved and die as the distended organ presses on vessels and impairs blood flow. The dead cells slough off, and an exudate covers ulcerated areas, causing the gallbladder to adhere to surrounding structures.

Signs and symptoms

·         Acute abdominal pain in the right upper quadrant that may radiate to the back, between the shoulders, or to the front of the chest; typically occurs after a fatty meal

·         Colic

·         Nausea and vomiting

·         Chills, low-grade fever

·         Jaundice

Diagnostic test results

·         X-ray reveals gallstones if they contain enough calcium to be radiopaque; also helps disclose porcelain gallbladder (hard, brittle gallbladder due to calcium deposited in wall), limy bile, and gallstone ileus.

·         Computed tomography scan or magnetic resonance imaging show calcified gallbladder and the presence of stones.

·         Ultrasonography detects gallstones as small as 2 mm and distinguishes between obstructive and nonobstructive jaundice.

·         Technetium-labeled scan reveals cystic duct obstruction and acute or chronic cholecystitis if ultrasound doesn't visualize the gallbladder.

·         Percutaneous transhepatic cholangiography supports the diagnosis of obstructive jaundice and reveals calculi in the ducts.

·         Blood chemistry reveals elevated levels of serum alkaline phosphate, lactate dehydrogenase, aspartate aminotransferase, and total bilirubin; serum amylase level slightly elevated; and icteric index elevated.

·         Blood studies reveal slightly elevated white blood cell counts during cholecystitis attack.

Treatment

·         Cholecystectomy

·         Choledochostomy

·         Percutaneous transhepatic cholecystostomy

·         Endoscopic retrograde cholangiopancreatography

·         Lithotripsy

·         Oral chenodeoxycholic acid or ursodeoxycholic acid

·         Low-fat diet

·         Vitamin K

·         Antibiotics

·         Nasogastric intubation

P.163

PRESENCE OF GALLSTONES

image