By Gregory E. Jeansonne
All information condensed from Schwartz: Principles of Surgery & Companion Handbook.
Background Information: Patients are predisposed to Cholelithiasis (aka Gallstones) by the 4 F's (Fat">
By Gregory E. Jeansonne
All information condensed from Schwartz: Principles of Surgery & Companion Handbook.
Background Information: Patients are predisposed to Cholelithiasis (aka Gallstones) by the 4 F's (Fat, Forty, Female, and Fertile).
Anatomy:
Duct System: Right and Left Hepatic Ducts form the 3-4cm Common Hepatic Duct. In
turn the Cystic Duct (from the Gallbladder, see below) joins the Common Hepatic Duct
creating the Common Bile Duct which is 8-11.5cm. The Common Bile Duct enters the
duodenum via the ampulla of Vater with its sphincter of Oddi. The pancreatic duct
may or may not join with the common bile duct prior to the duodenum.
Gallbladder: Located between the right and left hepatic lobes, in the hepatic bed, the
gallbladder has 4 parts: 1) Fundus, primarily smooth muscle, thinnest/weakest wall, 2)
Corpus or Body, primary storage site (50ml capacity), primarily elastic tissue, tapers
into the 3) Neck, which usually has a dilitation called the 4) Infundibulum or Hartmann's
Pouch. The Neck conects with the Cystic duct which contains the valves of Heister.
Histology of the lumenal lining is High Columnar Epithelium. Mucus production
is focused in the neck and infundibulumglobular cells and is transported to the lumen via
tubular alveolar glands. Blood Supply is via the cystic artery, a branch of the
right hepatic artery.
Anomalies: Are Common. The above description only accounts for 1/3 of patients. Variations occur in the mesentery (increasing likelihood of torsion), location (intrahepatic gallbladder increases chance of stone formation), accessory ducts (15% of patients, of note, small ducts called Ducts of Luschka may enter the gallbladder directly. If unrecognized they may allow bile leakage.), blood vessel anomalies (50% of patients).
Physiology:
Bile Formation: The liver produces 250-1000ml of bile per day under neural (vagal
increases, splanchnic decreases), hormonal (secretin increases), and chemical control
(alkali increases production). Composed of Water, Electrolytes, Bile Salts/Acids
(Cholic & Deoxycholic=>reduce cholesterol synthesis & increase absorption),
Proteins. Lipids, and Bile Pigments (Bilirubin Diglucuronide from hemoglobin
breakdown=> Urobilinogen).
Gallbladder Function: Concentrates bile salts/acids, cholesterol, and bile pigments x 10 over liver bile. Secretes mucus @20ml/hr. Cholecystokinin (CCK) released by the duodenum => contraction of gallbladder & sphincter of Oddi relaxation. Motilin regulates sphincter of Oddi tone (normal=30cmH2O, post-prandial=10cmH2O) => controls relative rate of continuous gradual bile release. 4/5ths of bile salts/acids are reabsorbed in the terminal ileum & another 15% in the colon after bacterial deconjugation.
Imaging
Ultrasound: Best choice, most widely used. Identify calculi (95%), and duct
dilitation (90%).
Plain Film: Limited value. Used to exclude other causes of abdominal pain. Only identify calculi 15-20% (Calcium containing stones only), "porcelain" gallbladder, or emphasymatous cholecystitis (gas in gallbladder wall => very bad sign).
Oral Cholecystography: Historically important (per Graham & Cole @1924). Oral contrast is absorbed and secreted by liver into bile canaliculi then concentrated within the gallbladder. Allows gallstone visualization & assesses gallbladder concentrating ability. Poor patient compliance, GI dysfunction, Liver Dysfunction => False Positive => Unnecessary Surgery. Largely replaced by abdominal U/S.
CT / MRI Scans: Good for biliary tract evaluation and adjacent structures. Poor for stone identification.
Scintigraphy (aka HIDA scan): IV Technetium 99m labeled Iminodiacetic acid is cleared by Kupffer cells and concentrated within gallbladder/biliary system.
Percutaneous Transhepatic Cholangiogram (PTC): Flouroscopic guidance of needle into bile duct. Allows injection of contrast for cholangiogram, or therapeutic intervention. Useful with complex biliary disease or patient unable to withstand surgery.
Endoscopic Retrograde Cholangiopancreatogram (ERCP): Endoscopic intubation of ampulla of Vater. Benefits similar to PTC.
Choledochoscopy: Adjunct to operative cholangiogram. Can aid in removal of internal obstructions or biopsy.
Pathophsyiology
Trauma: Primarily Iatrogenic. Release of sterile bile is well tolerated (chemical
peritonitis). Release of infected bile can lead to fulminant often fatal infective
peritonitis. Site of leak best defined by PTC or ERCP. Sharp transection can
be reanastomosed primarily but 50% will have stricture formation. Alternative is
anastomosis to Roux-en-Y of jejunum.
Gallstones:Form as a result of precipitation of bile component(s) due to imbalance between lecithin, cholesterol, and bile salts/acids within gallbladder. Asymptomatic gallstones should not be treated unless patient is an elderly diabetic or will be isolated from medical care for an extended period. Cystic duct obstruction leads to temporary / recurrent biliary colic (RUQ pain radiating to shoulder or scapula initiated by fatty meal). Common duct obstruction causes similar RUQ pain, jaundice, pale stools, and dark urine. May lead to ascending cholangitis, hepatic involvement, or pancreatic involvement. Mirizzi's Syndrome is a Hartmann's pouch stone encroaching on and eroding the common bile duct. Large gallstones can erode from the gallbladder directly into the duodenum (biliary enteric fistula). If the stone impacts (normally in terminal ileum), can lead to gallstone ileus (normally pass is less than 2-3cm).
Symptomatology:
Charcot's Triad: Jaundice, Fever & Chills, and RUQ Pain.
Reynold's Pentad: add Shock, and CNS depression.
Treatment:
Prophylactic Antibiotics: For patinets with jaundice, common duct stones, diabetes, or
over 65yo.
Cholecystostomy: As Temporizing measure or for patient unable to withstand surgery.
Cholecystectomy: Preferred Treatment in majority of cases. Can be performed open or laparoscopically.
Procedure: See Operation Procedure.
Revised: August 05, 2002.