Surgical approaches to extrahepatic biliary tract obstruction in ... ... 3.1 Anatomy of the biliary

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  • Surgical approaches to extrahepatic biliary

    tract obstruction in cats

    Word count: 11829

    Esmeralda Komdeur Student number: 01301173

    Supervisor: Prof. dr. Hilde de Rooster

    Supervisor: Dr. Erika Bianchini

    A dissertation submitted to Ghent University in partial fulfilment of the requirements for the degree of

    Master of Veterinary Medicine

    Academic year: 2018 - 2019

  • Ghent University, its employees and/or students, give no warranty that the information provided in

    this thesis is accurate or exhaustive, nor that the content of this thesis will not constitute or result in

    any infringement of third-party rights.

    Ghent University, its employees and/or students do not accept any liability or responsibility for any

    use which may be made of the content or information given in the thesis, nor for any reliance which

    may be placed on any advice or information provided in this thesis.

  • Voorwoord

    In de eerste plaats wil ik mijn promotor ontzettend bedanken voor alle adviezen en opbouwende commentaren zij mij gegeven heeft. Hier heb ik heel veel aan gehad. Ook wil ik mijn co-promotor bedanken. Als laatste wil ik dank brengen aan alle eigenaren, die zo vriendelijk zijn geweest om mij informatie te geven over hun huisdier, zodat ik van begin tot eind heb kunnen weergeven wat er met de patiënten is gebeurt.

  • Inhoudsopgave

    Titel Pagina

    1. Samenvatting 1

    2. Lijst met afkortingen 2

    3. Introduction 3

    3.1 Anatomy of the biliary system of the cat 3

    3.2 Physiology of bile 3

    3.3 Extrahepatic biliary tract obstruction in cats 4

    4. Case series 5

    4.1 Materials and Methods 5

    4.2 Results 5

    4.2.1 Macroscopic anatomy of the biliary tract 5

    4.2.2 Patient details 6

    4.2.3 Clinical symptoms 6

    4.2.4 Laboratory results 7

    4.2.5 Abdominal ultrasound 8 Secondary changes caused by EHBO 8 Location and possible cause of obstruction 8

    4.2.6 Microbiology and histopathology 9

    4.2.7 Surgical approach 10 Complications 11 Hospitalisation 11

    4.2.8 Postoperative morbidity and mortality 12

    5. Discussion 14

    6. Conclusion 19

    7. References 20

  • 1

    1. Samenvatting

    Galgangpathologie is niet veelvoorkomend bij de kat. In deze gevallenstudie worden 12 katten sinds

    Januari 2014 opgevolgd vanaf het moment dat ze werden aangeboden op de faculteit tot april 2019,

    waarin de laatste eigenaren gecontacteerd werden om te evalueren hoe het momenteel met hun

    huisdier ging. Het diagnostisch proces, met daarin de verschillende testen die werden uitgevoerd,

    wordt beschreven en de resultaten zijn in tabellen te zien. Na het stellen van de diagnose van

    extrahepatische galgangobstructie werden alle katten geopereerd. Afhankelijk van de plaats van de

    obstructie werden er verschillende operatietechnieken toegepast. Sommige katten werden een

    tweede keer geopereerd in verband met het opnieuw optreden of aanwezig blijven van symptomen.

    Tijdens en na de hospitalisatie periode traden er een tal van complicaties op. Niet alle katten hebben

    de hospitalisatieperiode overleefd. De katten die de kliniek hebben verlaten, werden ingedeeld in een

    korte termijn en een lange termijn groep om hierin de complicaties en mortaliteit te kunnen

    beoordelen. De mortaliteitscijfers zijn hoog. De meeste katten zijn in de korte termijn tijdsperiode

    overleden. De resultaten bij de 12 bestudeerde katten werden vergeleken met wat er in de literatuur

    beschreven staat.


    Biliary tract disease is uncommon in the cat. In this case series, 12 cats were followed up since January

    2014 from the moment of admittance to the Faculty Clinic until April 2019, when the last owners were

    contacted to evaluate the wellbeing of their pet. The diagnostic procedures are described and the

    results are shown in tables. After the cats were diagnosed with extrahepatic biliary tract obstruction,

    they were operated. Depending on the localisation of the obstruction, different types of surgery were

    performed. Some cats were operated twice, due to remaining or reoccurring symptoms. During and

    after the hospitalisation period a number of complications occurred. Not all the cats survived the

    hospitalisation period. The cats that were discharged from the hospital were divided in a short-term

    and a long-term group, to assess complications and mortality. The mortality rate is high. Most cats died

    during the short-term time period. The findings in the 12 cats that were included were compared to

    the literature.

  • 2

    2. Lijst met afkortingen:

    ALP: alkalic phosphatase

    ALT: alanine aminotransferase

    aPTT: activated partial thromboplastin time

    AST: aspartate aminotransferase

    CKD: chronic kidney disease

    E. coli: Escherichia coli

    EHBO: extrahepatic biliary tract obstruction

    Fr: French gauge

    GGT: gamma-glutamyl transferase

    HCT: haematocrit

    IRIS: international renal interest society

    μmol/L: micromole per litre

    NA: not available

    S. felis: Staphylococcus felis

    PT: prothrombin time

    U/L: units per litre

  • 3

    Fig. 1 Plastic model of the feline biliary tract 1. Gallbladder; 2. Cystic duct; 3. Common bile duct; 4. Hepatic ducts; 5. Lobar ducts

    3. Introduction

    3.1 Anatomy of the biliary system of the cat

    The gallbladder is a pear-shaped organ, which lies in a fossa between liver lobes; on the medial side

    there is the quadrate lobe, on the lateral side, the right medial lobe. The biliary tract consists of an

    intra- and extrahepatic part (Fig 1). Bile is secreted by the hepatocytes into the canaliculi; these

    capillaries are situated between the hepatocytes, but they don’t have epithelial lining. From there, the

    bile flows through the interlobular and lobar ducts towards the extrahepatic tract. The bile leaves the

    liver via the hepatic ducts and is drained into the gallbladder through the common bile duct and cystic

    duct. The part of the extrahepatic biliary tract between the gallbladder and the first hepatic duct is

    named the cystic duct; the part between the first hepatic duct and the duodenal papilla is the common

    bile duct (König et al., 2004). In the gallbladder, bile is stored before being delivered to the duodenal

    lumen (Center, 2009).

    The sphincter of Oddi surrounds the duodenal papilla and

    forms a natural barrier between the biliary tract and the

    duodenum. It should prevent intestinal contents entering

    the biliary tract. Normal bile is sterile and under normal

    circumstances, the flow will only go in one direction (Sung

    et al., 1992; Mayhew, 2002; Mehler, 2006; Center, 2009;

    Mayhew and Weisse, 2012; Radlinsky, 2013). If the

    sphincter doesn’t function properly, intestinal contents

    can enter the biliary tract and ascend in the direction of

    the gallbladder. In case of a mechanical obstruction in the

    biliary tract, the bile can’t flow. As a result of this biliary

    stasis, the bile will thicken and form sludge that might lead

    to occlusion of the extrahepatic biliary tract (Center,


    In 80 % of the cats, the pancreatic duct joins the common bile duct before entering the duodenum through the papilla (Etue et al., 2001). Because of this particular anatomic feature pathologies of the pancreas can have an effect on the biliary tract and vice versa (Mayhew et al., 2002; Jergens, 2012).

    3.2 Physiology of bile

    Bile consists among others of bile salts, bilirubin, electrolytes and water. The hepatocytes have

    transporters that are involved in the formation of bile; bile acids are actively pumped to the canaliculi

    by these transporters. In the cat, these bile acids are conjugated only to taurine (Center, 2009). The

    hepatocytes also excrete bilirubin into the canaliculi (Mayhew and Weisse, 2008). Water and

    electrolytes follow through osmosis. When the bile flows through the biliary tract, there is secretion

    and absorption of water and electrolytes, modifying the bile (Center, 2009). The function of the

    gallbladder is to store and concentrate bile (Center, 2009). If an animal is sober, the gallbladder is

    relaxed and filled.

  • 4

    One of the functions of bile is to bind endotoxins (Mayhew and Weisse, 2008). When endotoxins are

    bound to bile salts, there is less chance of absorption and endotoxemia. Another function of bile is to

    emulsify fats. Emulsified fats are easier to digest and absorb. Bile also plays a role in the absorption of

    fat-soluble vitamins A, D, E and K. When bile salts are not present in the intestine, these vitamins are

    less absorbed.