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  • 8 Biliary Diseases

    ANATOMY OF THE EXTRAHEPATIC BILIARY SYSTEM Anatomy of the biliary system is highly

    variable,andthisincludesducts,arteries,veins,andlymphatics.

    Common Hepatic Duct Intrahepatic biliary duct systems converge onrightandlefthepaticducts.

    Right and left hepatic ducts typically form thecommonhepaticduct.

    Leftductisusuallylonger. Junctionoftheductsmaybeintrahepatic(e.g.,inhepatomegaly).

    Accessoryhepaticductscanoccur. There may be no common hepatic ductif the cystic duct empties into right and lefthepatic duct junction (bile duct branchvariant).

    Gallbladder NormallyliesbetweenhepaticsegmentsIVandV, in a ventral fossa between the anatomicalrightandleftlobes

    Ventralsurfacetypicallyliesincontactwiththedescendingpartoftheduodenum.

  • 96 Biliary Diseases

    Right and lefthepatic ducts

    Commonhepatic duct

    (Common)bile duct

    Cysticartery

    Cystic duct

    Gallbladder

    Right and lefthepaticarteries

    Proper hepaticartery

    Commonhepaticartery

    Hepatic ductsCystic duct

    Right LeftSpiralfold

    Smoothpart

    Commonhepaticduct

    NeckInfundibulum(Hartmannspouch)

    Body

    Fundus

    Hepatopancreaticampulla (of Vater)

    Descending(2nd) part ofduodenum Pancreatic

    duct

    (Common)bile duct

    Viscera: Gallbladder and Extrahepatic Ducts

  • 97 Biliary Diseases

    Peritoneum surrounds fundus and attachesbody and neck to the ventral surface of theliver.

    Hepatic surface of the gallbladder has fibroustissueconnectionstolivercapsule.

    Mucosan Columnarepithelium,nosubmucosan ActivelyabsorbsNa+andwater,concentratingbile

    Smoothmuscleofthefibromuscularlayerispri-marilyorientedlongitudinally.

    Parasympatheticpreganglionicinnervationfromleft(anterior)vagusfiberscontractsgallbladderandrelaxesbileductsphincter.

    Postganglionic sympathetic fibers from theceliacganglionaredrivenbypreganglionicfibersfromT7-T10spinalsegmentstravelingingreatersplanchnicnerves.

    Visceral afferent fibers (e.g., pain) travel backtoward thoracic spinal ganglia, through theceliac plexus and greater splanchnic nerve,alongsideincomingsympathetics.

    Cystic Duct Proximalportionisconvoluted;spiralfoldkeepstheductopen.

    Distalportionissmooth. Typical cystic duct joins the common hepaticductwellbelow the rightand lefthepaticductjunction.

    Triangle of Calot: classic configuration (shownabove)withcysticductright,commonbileductleft,liverabove,andrighthepaticarterypassingthrough

  • 98 Biliary Diseases

    Low unionwith commonhepatic duct

    Adherent tocommonhepatic duct

    Highunion withcommonhepaticduct

    Cystic ductabsent orvery short

    Anterior spiraljoining commonhepatic duct onleft side

    Posterior spiraljoining commonhepatic duct onleft side

    Joiningcommonhepatic duct

    Joiningcystic duct

    Variations in cystic duct

    Accessory (aberrant) hepatic ducts

    Joining(common)bile duct

    Joininggallbladder Two accessory

    hepatic ducts

    Variations in Cystic and Hepatic Ducts

  • 99 Biliary Diseases

    Cystohepatic Junction Classicnormal

    n High, sub-hepatic origin of the commonhepaticduct

    n Joinedinferiorly,atananglefromtheright,bythecysticduct(

  • 100 Biliary Diseases

    Dimensions 4-8mmdiameternormalundilated Diametertendstoincreasewithadvancedage. Heuristic:normalductdiameterinmm=age/10

    Hepatopancreatic Ampulla (Vater) Formedbytheunionofthe(common)bileductandthemainpancreaticduct

    Ampulla empties posteromedially through themajorduodenalpapilla(ofVater)intotheretro-peritoneal, descending (second) part of theduodenum.

    Hepatopancreatic sphincter (of Oddi): formedfromacomplexof smoothmuscle surroundingtheterminalpartoftheampullaanditscontrib-utingduct

    Bile Secretion Increased by cholecystokinin (CCK), secretin,andvagalactivity

    Decreased by vasoactive intestinal peptide(VIP),somatostatin,sympatheticactivity

    CCKcausestonicgallbladdercontraction. Bilemediatesabsorptionoffat-solublevitaminsandexcretionofbilirubinandcholesterol.

    VESSELS AND LYMPHATICSArteries Gallbladderissuppliedbycysticartery,typicallya branch of the right hepatic artery (from thehepatic artery proper, off common hepatic,celiacaxis).

    Source and course of the cystic artery vary widely: this must be carefully determined incholecystectomy.

  • 101 Biliary Diseases

    Right hepaticartery

    Cystic artery

    Cystohepatictriangle(of Calot)

    Cystic duct

    Commonhepaticduct

    (Common)bile duct

    Supraduodenalartery

    Gastroduodenalartery

    Left hepaticartery Common hepatic

    artery

    Celiac trunk

    Biliary System Arteries

    Variants includeorigins fromcommonhepatic,left hepatic, superior mesenteric arteries,passing anterior or posterior tohepatic or bileducts.

    Bile ducts: supplied by branches of posteriorsuperior pancreaticoduodenal, retroduodenal,right,andlefthepaticarteries(celiacaxis)

  • 102 Biliary Diseases

    Veins Cystic veins are variable; veins from the bodytypicallypassdirectlyintothelivertodrainintohepaticsinusoids.

    Otherveinsfromtheneckandcysticducttypi-callydraindirectlyintotherightportalvenoussystem, and other veins drain the biliary ductsystem.

    Lymphatics Cysticlymphnodesclusteraroundtheneck. Cysticlymphaticsalsodrainintohepaticnodesclusteredaroundtheupperbileduct.

    Deeper drainage into celiac nodes around thearterialtrunk

    CLINICAL CORRELATESNormal Bile Production 500to1000mL/day Secretin production and meals rich in fatsincreasebileproduction.

    Bile constituents: electrolytes, bile salts, pro-teins,cholesterol,fats,andbilepigments

    Major salts: cholic, deoxycholic, and chenode-oxycholic acids; anionic and conjugated withtaurineorglycine

    Contains unesterified cholesterol, lecithin, andfattyacids

    pHof5.6-8.6isnormalrange.n Morealkalineathighersecretionratesn Moreacidicwithproteininmeals

    Cholesterolsolubilityandlackofstoneprecipi-tationdependonabalanceamongcholesterol,bilesalts,andlecithin(inmicelles).

  • 103 Biliary Diseases

    Left gastricnodes

    Hepaticnodes

    Celiac nodes

    Pyloricnodes

    Cystic node(of Calot)

    Pancreatico-duodenalnodes

    Hepatic nodesaround bileducts andproper hepaticartery

    Lymph Vessels and Nodes of Pancreas

  • 104 Biliary Diseases

    Gallbladderalsosecretesmucus,whichprotectstissuesfromthelyticactionofbile.

    Control of Bile Secretion Bile produced by the liver is shunted to thegallbladder,withthesphincterofOdditonicallyclosed(betweenmeals).

    Cholecystokininissecretedbyintestinalmucosainresponsetoingestionoffood.

    Gallbladder contracts and pushes bile into theductalsystem.

    Sphincter ofOddi relaxes, and bile is releasedintoduodenum.

    Cholelithiasis Incidence: about 10% of the population, withmostasymptomatic

    Diabeticsnot at increased risk, though inflam-matory responses can complicate late-detectedcases,withhigherincidenceofopensurgery

    Onlyabout10%ofbilestonesareradiopaque. Nonpigmentedstones

    n MostcommontypeinU.S.(~75%)n Increasedinsolubilizationofcholesteroln Factors can include cholestasis, increasedH2O reabsorption, Ca2+ nucleation bymucinglycoprotein, and decrease in bile acids andlecithin.

    Pigmentedstonesn Occurrence ~25% in U.S., most commonworldwide

    n Precipitationofcalciumbilirubinateandinsol-ublesalts,withsolubilizationofunconjugatedbilirubin

  • 105 Biliary Diseases

    Mechanisms of biliary pain

    Visceral pain, mediated bysplanchnic nerve, results fromincreased intraluminal pressure and distention caused by suddencalculous obstruction of cystic orcommon duct.

    Sites of pain in bilary colic

    Sites of pain and hyperesthesiain acute cholecystitis

    Patient lies motionlessbecause jarring or respiration increasespain. Nausea is common.

    Parietal epigastric or rightupper quadrant pain results fromischemia and inflammation of gall-bladder wall caused by persistentcalculous obstruction of cystic duct.Prostaglandins are released.

    Sudden obstruction(biliary colic)

    Persistent obstruction(acute cholecystitis)

    Calculus in Hartmannspouch

    Edema, ischemia,and transmuralinflammation

    Transduodenalview ofbulging of ampulla

    Ampullarystone

    Calculus in common duct

    Cholelithiasis

  • 106 Biliary Diseases

    n Black stones may be caused by cirrhosis,hemolyticdisorders,ilealresection,orchronictotalparenteralnutrition(TPN).

    n Usuallyfoundonlyinthegallbladder

    Diagnostic Procedures Liverandbiliaryfunctiontests

    n Serumalkalinephosphatase:verysensitivetoobstruction; sensitivity increased by isoen-zymedatabloodlevels

    n Serumglutamic-oxaloacetictransferase(AST/SGOT)bloodlevels

    n Serum glutamate-pyruvate transaminase(ALT/SGPT)bloodlevels

    n Lacticaciddehydrogenase(LDH)bloodlevelsn Bloodbilirubinlevels

    Ultrasoundn Often the first test ordered for suspectedbiliarytractdisease

    n Safe,inexpensiven 95% sensitivity for stones, identifies gallblad-dermorphologyandmechanicalvs.metabolicsourcesofjaundice

    Endoscopic retrograde cholangiopancreatogra-phy(ERCP)n Catheter from a side-viewing endoscope isinsertedintotheampullaofVater.

    n Contrastagentisinjected.n Radiographsaretaken.n Devicecanperformsphincterotomyifneeded.n Standing questions:What are indications forperforming an ERCP before a lap chole?Blockedbileduct?May identifyvariantsandreduceinjuries?

  • 107 Biliary Diseases

    Cholecystitis Gallbladderwalldistentionandinflammation Mostcommoncauseisobstructionofthecysticductbyastone.

    Classic right upper quadrant pain referred torightscapulaandshoulder

    Pain mediated by segmental v