Gall Bladder Mucocele in Dogs Diagnosis and Medical Management - JULIE STEGEMAN, DVM, DACVIM SOUTHERN CALIFORNIA VETERINARY SPECIALTY HOSPITAL

Gall Bladder Mucocele in Dogs
    Diagnosis and Medical
         Management

    JULIE STEGEMAN, DVM, DACVIM
  SOUTHERN CALIFORNIA VETERINARY
         SPECIALTY HOSPITAL

Mucocele Definition

 Mucocele= distension of a cavity due to
  accumulation of mucus.
 Biliary mucocele= gall bladder full of thick green-
  black bile-laden semisolid to immobile mucoid mass
 AKA:
    Inspissated bile
    Mucinous hyperplasia
    Cystic mucinous hypertrophy
    Mucinous cholecystitis
    Cystic glandular cholecystitis

History

 1965 first description as a finding in older dogs on
  necropsy
 1984 Case report in JAVMA- ruptured mucocele
 1989 described in Ettinger, 1993 Pathology Text
 1995 Newell et al JAAHA reported on two non-
  ruptured mucoceles
    Mucocele was thought to develop from extrahepatic bilary
     obstruction
    Scintigraphy used to determine obstruction
    Icterus and vomiting recurred several months post-
     cholecystectomy in both dogs

History

 Gall bladder mucocele is now very commonly
 reported
    Increased use of ultrasound versus increased awareness???
    Spike in literature reports since early 1990s
    Possible that necrotizing cholecystitis cases were mucoceles
 50% of biliary rupture cases now seen are mucocele
   Crews et. al. JAVMA 2009

Etiology

 Ligation of CBD does NOT induce mucocele.
 Cystic hyperplasia of mucus-secreting cells lining the
  gall bladder to protect from bile salt damage
 Increased bile salt exposure with cholestasis
    Gall bladder hypomotility
    Increased water absorption from gall bladder lumen
 Sludge= cholesterol crystals + precipitated pigments
 + bile salts
    SEDIMENTS during the ultrasound exam
    May be a risk factor for some dogs

Etiology

 Accumulation of mucinous material in gall bladder
  with limited outflow induces pressure necrosis on
  biliary wall
 May be asymptomatic until time of rupture
 Important effects on the liver as well
    Biliary stasis and hyperplasia
    Suppurative cholangitis
    Periportal mixed cell hepatitis
    Periportal fibrosis

Histopathology

Risk Factors

 Breed association- Shelties, Cockers, Miniature
    Schnauzers, (Beagles, Miniature Poodle,
    Maltese,Bichon Frise)
   Hyperlipidemia, hypercholesterolemia
   High fat diets
   Hyperadrenocorticism
   Steroidogenic medications
   Hypothyroidism +/-
   NOT associated w/ diabetes

Steroids and Mucoceles

 23% of Mucocele patients had Cushing’s Disease
   Pike et al JAVMA 2004

 Dogs with hyperadrenocorticism have 29 times the
 risk of developing mucocele versus dogs without it
    Mosich et al JSAP 2009
 Effect of steroids on gall bladder motility and/or bile
  salt composition?
 Effect of hyperlipidemia?
 ALL dogs with mucocele should be screened in some
  way for hyperadrenocorticism and hypothyroidism

Clinical Presentation

 Median age 9 years, either sex
 Any breed, but predispositions as listed previously
 May be completely asymptomatic, just elevated liver
  enzymes
 Symptoms
    Anorexia
    Abdominal pain
    Vomiting, possible diarrhea
    Possible fever
    Possibly polydipsic

Clinical Pathology

 Elevated ALKP (11-15X)
 Elevated GGT (2-8X)
 Elevated ALT (4-6X)
 Elevated Cholesterol (approx 75% of cases)
 Elevated T bili +/- (approx 50%)
 Leukocytosis +/-
 Hypoalbuminemia +/-
 Pancreatitis is not uncommon comorbid condition

Differential Diagnosis

 Pancreatitis with extrahepatic biliary obstruction
 Cholecystitis
 Acute hepatitis
 Leptospirosis
 Biliary mucocele

Sonographic diagnosis

Classic “kiwi” appearance

Other ultrasound variations

Biliary Rupture

 Ultrasound is 86% sensitive to detect rupture
 Abdominal fluid bili > serum bili
 Cytology of Abdominal fluid- basophilic laminated,
 fibrillar strands of material

                                        JAVMA July 1,2011

Biliary rupture

Treatment

 Cholecystectomy is primary treatment
 Cholecystotomy and lavage NOT advised (recurs)
 +/- Prognosis worse if ruptured
 +/- Prognosis worse if infected
   CULTURE!!

   Enterobacter, E coli, Enterococcus, Staph

   Fluoroquinolone + Metronidazole vs Clavamox alone

 Older age and leukocytosis also may be negative
 prognostic factors

Postoperative care

 Antibiotics for several weeks afterward if culture +
 Ursodiol long term 10-15 mg/kg SID with food to
    ensure choleresis
   Low Fat diet
   CBD may remain dilated in about 30%
   Monitor liver enzymes- periportal hepatitis may
    continue and require therapy
   Postoperative or concurrent pancreatitis needs to be
    managed

5 months postop cholecystectomy
    7 yr F/S Cocker Spaniel

Medical Therapy

 Only advisable if patient is asymptomatic and
    surgery is either high risk or declined by owner
   Ursodiol 20-25 mg/kg/day (high dose)
   Antibiotics +/- (Clavamox , or Fluoroquinolone +
    Metronidazole)
   S-adenosyl methionine 40 mg/kg/day (high dose)
   Low Fat Diet
   Identify and treat endocrinopathies!
   Walter et al JAVMA ‘08, 2 cases resolved with above.
   MUST FOLLOW CLOSELY!

Medical Therapy- an example

                          “After” 2 months on
“Before”
                          medical Tx

Medical Therapy

“Before”                             “After”- 5 months later

12 yr Miniature Schnauzer            ( Walter et al JAVMA June 2008)

Mucocele and inflammatory hepatopathy

 I am seeing more cases of granulomatous hepatitis
  and other inflammatory hepatitis that resolve on
  immune suppressive medications, only to relapse
  with fever and icterus, and the gall bladder is the
  source. Some have early mucocele changes- from the
  steroids used to treat the disease?
 Should we take out gall bladders in our chronic
  hepatitis cases??? Which ones??

Mucocele –Hepatitis connection?

Early Detection/ Genetics

 Bile viscosity determined by concentration of mucin
    and phospholipids
   Phosphatidlycholine forms a micell with bile salts to
    solubilize and mobilize them.
   Low PC levels can lead to increased bile salt damage
    to biliary epithelium.
   ABCB4= translocates PC from hepatocyte to biliary
    canalicular lumen
   There is a mutation in ABCB4 in Shelties
       Dominant w/ incomplete penetrance.

Surgical Management

 Doctor Gassel………