Week 5 - GI Flashcards
Where is the gallbladder located?
between quadrate and right medial lobes
How many hepatic ducts do dogs and cats have?
Dogs → 2-7
Cats → 1-5
Where does the commons bile duct lie?
from first hepatic duct to major duodenal papilla
What blood vessels supply the liver?
-Hepatic artery (20% of blood supply and 50% of O2) – more oxygenated blood
-Portal vein (80% of blood supply and 50% of O2)
What is the blood supply for the gallbladder?
Cystic artery (branch of hepatic artery)
Cholecystectomy is what?
Removal of gallbladder, stops at cystic duct
What is the ductal anatomy for a dog and cat? What’s the main difference?
Dogs
-Major duodenal papilla: Exit for CBD + Pancreatic duct SEPARATELY
-Minor duodenal papilla:: Exit for accessory pancreatic duct (V. IMP)
Cats
-Major duodenal papilla: Exit for CONJOINED CBD + PD
-Minor duodenal papilla: Only present in 20% of cats
Major difference: only 20% of cats have minor duodenal papilla. so if you damage the major duodenal papilla, you’ll have ramifications
What are some pre-operative considerations for hepatic surgery?
- hemorrhage
-Bleeding can be profuse and life-threatening
-Check coagulation profiles
-Blood type and cross-match patients
-Consider pre-treatment in some patients
-Be familiar with surgical techniques to prevent massive bleeding (e.g. use of stapling devices, pringle maneuver etc.) - hypoglycemia
-Rarely a major problem in hepatic resections
-Can occur in very small or debilitated patients - Anesthesia/drug metabolism
-Avoid drugs that undergo hepatic metabolism or are hepatotoxic
4.Bacteria
-Significant proportion of cats and dogs have resident hepatic microflora of mostly enteric origin
-Bile cultures more likely to yield positive culture than hepatic parenchyma
–make sure to empty entire gallbladder to prevent leakage and so hole can heal without leakage
-Good empirical choices of antibiotics
–fluoroquinolone with amoxicillin-clavulanate or clindamycin
What are the 3 indications for liver surgery?
- Liver biopsy
‣ For investigation of diffuse hepatopathies or mass lesions - Liver lobectomy
‣ Neoplasia
‣ Liver abscesses
‣ Liver lobe torsion
‣ Trauma - intrahepatic portosystemic shunt
‣ Mostly treated using an interventional stent and coil approach
What are the 4 techniques for a liver biopsy?
- SUTURE FRACTURE TECHNIQUE
-for diffuse hepatopathy - look for a liver lobe with pointed margin
-Blood vessels and bile ducts will be ligated - PLACEMENT OF OVERLAPPING SUTURES
-Helpful when areas that cannot be easily looped around need to be sampled
-Overlapping suture bites are taken to prevent bleeding - SKIN PUNCH TECHNIQUE
-Skin punch used to harvest biopsy “cylinder”
-Can fill biopsy holes with cores of gelatin sponge - LAPAROSCOPIC LIVER BIOPSY
-Subumbilical camera port, one instrument port in cranial left or right quadrant
What should you consider when biopsying a mass lesion off the liver?
▸ Many are very vascular and might bleed profusely
▸ If possible biopsy using a suture ligation technique for
added security or consider fine needle aspirate to see how
much it bleeds
▸ Other option is to go straight to liver lobectomy
What are tumor types of the liver?
‣ Metastatic lesions (most common)
‣ Primary liver tumors
-Hepatocellular carcinoma/adenoma - better prognosis than others
-Bile duct tumors (cholangiocellular carcinoma)
-Mesenchymal tumors
-Neuroendocrine tumors (carcinoids)
-Liver tumors can be massive, nodular or diffuse
CS of tumors: anorexia, lethargy, inappetence
What does a liver resection entail?
▪ Can be partial or complete
▪ Performed with blunt dissection and suture ligation or surgical staplers
‣ Thoracoabdominal stapler (TA-Covidien Inc.)
▪ Need knowledge of hepatic anatomy and blood supply
▪ Can resect up to approximately 70% of the liver acutely
How would you diagnose and treat a liver abscess?
▪ Uncommon, in older dogs with non-specific clinical signs: vomiting, lethargy, anorexia
▪ Can be single or multifocal
▪ Dx: Abdominal ultrasonography ± aspiration
▪ Micro-organisms: E. Coli, Staph spp. Enterococcus spp., Clostridium spp.
▪ Treatment:
‣ Medical: antibiotics and aspiration
‣ Surgical: lobectomy
‣ Drainage and alcoholization
Biliary tract surgeries encompass what dz/pathologies?
-mucoceles
-bile peritonitis
-extra hepatic biliary obx
What are the 3 classifications for extra hepatic biliary obx?
- extraluminal
-pancreatitis
-neoplasia - intraluminal
-cholelithiasis
-FB
-neoplasia - intramural
-neoplasia
▪ Inflammatory (~70%)
- Cholangiohepatitis (93%)
- Cholecystitis (89%)
- Cholelithiasis (40%)
- Pancreatitis (47%)
- Hepatic lipidosis (28%)
▪ Neoplastic (~30%)
- pancreatic adenocarcinoma
- biliary adenocarcinoma
▪ Occasional
- diaphragmatic hernia, fluke, FB
How do you diagnose EHBO?
▪ Hyperbilirubinemia
▪ Increased serum alkaline phosphatase, alanine
aminotransferase, gamma-glutamyl transferase
▪ Leucocytosis
▪ Hypoalbuminemia
▪ Urinalysis: Bilirubinuria or bilirubin crystals in the urine are
common.
▪ Coagulation profile: PT, PTT
▪ Fecal examination: Acholic feces, Trematode eggs - cats
▪ Plain radiography
-Cranial organomegaly
-Cholelithiasis – most radio-opaque
-peritonitis
▪ Abdominal ultrasound
-CBD & GB distension
-Note that distension doesn’t confirm obstruction
-Choleliths, neoplastic lesions, mucoceles
How does bile peritonitis happen? What causes it?
-Trauma
-Ruptured gall bladder mucocele
-Necrotizing cholecystitis
-Secondary to all causes of EHBO
Is bile peritonitis an emergency?
YES, it is an emergency
▪ Bile is an important adjuvant in peritonitis
▪ Causes chemical peritonitis
▪ Treatment of underlying leakage is imperative
▪ Thorough abdominal lavage
▪ Abdominal drainage – Open v. closed??
How do you DIAGNOSE bile peritonitis?
▪ Laboratory parameters:
-Hyperbilirubinemia
▪ Imaging
-Plain radiography
-Abdominal ultrasound
▪ Cytology of effusion
-bile pigments
▪ Abdominocentesis
-if bilirubin in effusion is ≥2X serum considered diagnostic
Examples of hepatic pathologies and coinciding surgeries:
▪ Cannot demonstrate patency of CBD
→ Biliary re-routing
▪ Functional EHBO but can catheterize
→ Biliary stenting/cholecystostomy
▪ Biliary mucocele/cholelithiasis/GB neoplasia or trauma
→ Cholecystectomy
▪ Traumatic injury to common bile duct
→ Primary closure or biliary rerouting
Why do mucoceles happen?
▪ Underlying lesion is cystic mucinous hyperplasia of gallbladder
▪ GB full of thick gel-like congealed bile
▪ C/S – from silent to EHBO ± rupture
What is the treatment of choice for mucoceles?
▪ Cholecystectomy is treatment of choice
How do you DIAGNOSE a mucocele?
▪ Primarily an ultrasonographic diagnosis
▪ Early lesion – bile sludge accumulation
- CAREFUL - Not all bile sludge
cases progress into mucocele
▪ Later – Classical stellate appearance (“kiwi” gall bladder)
-look like a kiwi
What is post-op care after liver surgery?
▪ Continued fluid therapy
▪ Electrolytes and acid-base status
▪ Nutrition
▪ Antibiotic therapy
▪ Open abdominal drainage if deemed necessary
What are post-op complications after liver surgery?
▪ Further leakage of bile
▪ Peritonitis
▪ Hemorrage
▪ Pancreatitis
▪ Re-obstruction of biliary tree
▪ Ascending cholangiohepatitis with re-routing procedures
▪ Sepsis
What are the 3 functions of the colon?
- Fermentation of and nutrient production from indigestible ingesta by colonic flora (mainly bacterial)
* Vitamins
* Short chain fatty acids
* Etc. - Electrolyte and water absorption (mainly ascending & transverse)
- Storage of feces (mainly descending colon)
What’s the difference between constipation and obstipation?
- Constipation - infrequent, difficult evacuation of dry/hard feces (still productive)
- Obstipation - severe constipation, unable to defecate (requires medical intervention)
What are some predisposing factors for feline constipation?
- Sedentary lifestyle
- Obesity?
- Hx of trauma
- Dehydration - like from CKD, etc
- Diet: some low fiber diets or diet high in indigestible material (e.g., bone fragments in cats that hunt)
- Underlying cause (see next)
What are functional obstipation? (vs. Mechanical)
-issue with colon propelling feces
- Neurologic disease
-Pelvic trauma (neurologic)
-Sacrocaudal luxations (AKA tail pull injuries)
-Dysautonomia
-Ganglionopathies (e.g., Hirschsprung’s disease) - Dehydration
-systemic disease (e.g., CKD, DM/DKA, chronic vomiting, neoplasia)
-lack of water access or anorexia - Electrolyte changes (severe)
-hypokalemia
-hypercalcemia
What are mechanical obstipation? (vs. Functional)
-physical obx
INTRALUMINAL
* colorectal masses
* Strictures
* atresia ani in kittens
* foreign bodies
EXTRAMURAL
* Orthopedic stenosis or fractures (trauma)
* masses
* pelvic trauma orthopedic, soft tissue
* Manx sacral deformity
Underlying causes for CONSTIPATION
- Idiopathic megacolon
-a diagnosis of exclusion
-cause unknown but suspected to be a disturbance in colonic smooth muscle contraction - Chronic enteropathy (anecdotally)
Top causes of feline OBSTIPATION
- Idiopathic megacolon (62%)
- Orthopedic (23%)
- Neurologic (11%) - hanging tail
What should a DIAGNOSTIC WORKUP for constipation/obstipation be?
- CBC
- Chemistry panel (with lytes)
- Urinalysis
- History
- Neurologic examination
- Sedated rectal exam
-Palpate for masses/ stricture/ stenosis
-Palpate pelvis for fractures/ stenosis - Radiographs
-Evaluation of amount and character of feces
-Evaluation of fractures, stenosis, mass, FB - Abdominal ultrasound
-extraluminal masses (similar to rads but
better soft tissue detail) - (Colonoscopy/proctoscopy)
-Intraluminal lesions (mass, stricture) - (Contrast radiographs)
-Barium enema if colonoscopy not possible
