hepatobiliary pt 5: portosystemic shunt cont. & review Qs Flashcards
Portosystemic Shunt: less common clinical signs / findings - size? kidneys? eyes? testicles?
- Small for age and breed
- Can have prominent kidneys
- Copper coloured irises in cats
- Intact males can be cryptorchid
Portosystemic Shunt: Diagnosis - CBC findings
- Microcytosis
Portosystemic Shunt: Diagnosis - urinalysis findings
- Low USG
- Ammonium biurate crystals
Portosystemic Shunt: Diagnosis - serum biochem findings
- Decreased albumin / total protein
- Decreased urea
- Decreased cholesterol
- Decreased glucose
- Mild elevation in ALP and/or ALT
Portosystemic Shunt: Diagnosis - bile acids? ammonia?
- Elevated pre and post-prandial bile acids (often marked), majority
- Elevated NH3 (not widely available)
Portosystemic Shunt: radiograph findings
- Small liver, enlarged kidneys
- Lack of portal perfusion, insulin, glucagon, and other trophic factors
- Urate calculi often radiolucent
Portosystemic Shunt: abdominal ultrasound findings
- Identification of abnormal blood vessel
- Assessment for urate calculi
- Other ‘footprints’ can include small liver, renomegaly
Portosystemic Shunt - when can we use CT angiography for Dx? what is its use?
- Helpful when ultrasound does not identify PSS despite clinical suspicion
- Outlines shunt anatomy which can increase surgical success
Portosystemic Shunt: Treatment options overview
- Initial stabilization for dogs with hepatic encephalopathy
- Long-term treatment of PSS:
> Surgical correction
> Medical management
Hepatic Encephalopathy: Treatment - 3 goals
- Alleviate neurologic signs
- Reduce incidence of predisposing factors
- Identify underlying hepatic condition for specific management
hepatic encephalopathy diet therapy considerations, esp protein and fiber
- Most dogs can have normal protein levels
- Feeding smaller, more frequent meals helps decrease protein load at once,
maintains appropriate calorie/protein nutrition - Mild and temporary protein restriction might be required – only in severe cases
- Avoid protein malnutrition
> Body protein breakdown will cause elevation in NH3
> Monitor BCS and MCS carefully - Fibre in diet helps trap ammonia, other toxins in feces for evacuation, decreases contact time of feces & bacteria
> Decrease ammonia / other toxin production and absorption
HE: Medical Therapy options
- Lactulose
- Antibiotic therapy
- Reduce triggers of HE
> Inflammation, infection
what is lactulose and what is its use in treating HE?
- Soluble fibre
- Acidifies colonic contents and traps ammonium ion in colon
- Promotes ammonia incorporation into bacteria
- Hastens colonic transit time (reduced time/ability for toxin absorption)
() - 2.5 to 5ml (cat); 2.5 to 15 ml (dog) every 8 hours
- Titrate dose to produce 2-3 soft stools per day
antibiotic therapy for HE? purpose?
- Amoxicillin, or metronidazole
- Decrease bacterial populations
- Decreases amount of toxin production in the intestinal tract
preferred treatment option for HE due to shunt?
- Surgical attenuation of the shunt is the preferred treatment option (referral surgery)
- Medical management
> Treatment for hepatic encephalopathy
Portosystemic Shunt: post surgical treatment medical therapy should be continued for how long
Post-operatively continue medical therapy for HE as liver function restored
* Generally discontinued by 8-12 weeks
Portosystemic Shunt: Surgical Outcomes: prognosis? what long term observations may we see?
- Good prognosis for normal life with attenuation of a single shunt
> Most dogs able to discontinue medical therapy 8-12 weeks post-op - Long-term, serum bile acids may remain abnormal
> Some degree of vessel changes (portal vein hypoplasia) in liver
Portosystemic Shunt: Surgical Outcomes - rate of surgical complications?
- Low rate of surgical complications
Portosystemic Shunt: Surgical Outcomes - what neuro problem do we sometimes see and how serious is it? how can we prevent?
- Post-operative seizures – can be very severe
- Pre-operative levetiracetam might reduce frequency and severity but evidence conflicting
what might preclude ligation for portosystemic shunt surgery?
Portal hypertension during shunt surgery might preclude ligation
* Uncommon
why can clinical signs sometimes persist after surgical treatment for portosystemic shunt?
- Some PSS ligations are only partial and a degree of clinical signs can persist
if a dog does not undergo surgery to correct portosystemic shunt, what other option should be continued?
- Continue treatment for HE if surgery not pursued
what dogs are good candidates for medical treatment of portosystemic shunt?
- Mildly affected dogs & older dogs are the best candidates for good
outcomes
> Small shunt fraction
PSS: Medical vs Surgical Treatment? which is better? are the others doomed?
- Overall, dogs undergoing surgery have better outcome
> Longer survival times
> Reduced long-term clinical signs - Dogs responding to medical management can do very well
> Mean survival times >2 years
> 1/5 of dogs survived >6 years in one study
> Recurrence of signs, uroliths
- Which of the following liver enzymes are considered due to hepatocellular leakage, and which are due to induction / cholestasis?
a) ALT
b) GGT
c) ALP
d) AST
Hepatocellular injury: ALT, AST
- Alanine transferase (ALT)
- Aspartate aminotransferase (AST)
Induced / Cholestasis: ALP, GGT
- Alkaline phosphatase (ALP)
- Gamma-glutamyl transferase (GGT)
- Also note: Bilirubin (stasis - not induced)
Which of the following is NOT a marker of decreased hepatic synthetic function (when decreased)?
a) Albumin
b) Creatinine
c) Urea
d) Cholesterol
b) Creatinine
Markers of decreased synthetic function:
* Decreased albumin
* Decreased cholesterol
* Decreased urea
* Decreased glucose
Identify the true statement:
a) Patients with lymphocytic cholangitis often present acutely ill and febrile
b) Ascites and elevated globulins is a common feature of neutrophilic cholangitis
c) E. coli is most common bacteria cultured from bile of cats with neutrophilic cholangitis
d) Hyperbilirubinemia is uncommon in cats with neutrophilic cholangitis
c) E. coli is most common bacteria cultured from bile of cats with neutrophilic cholangitis
- In what situations is an elevated ALT/ALP in an otherwise healthy patient concerning? (list 3)
- Any elevation in a cat (short half-lives
of enzymes) - Both ALT and ALP elevation
- > 2x upper limit in a dog
- Persistence
Which of the following medications decreases bile stasis and decreases toxicity of bile acids?
a) S-adenosylmethionine
b) D-penicillamine
c) Ursodiol
d) Prednisone
c) Ursodiol
A 6 month old male Yorkshire Terrier presents with a 2-day history of dull mentation, and episodes of apparent blindness today. Your initial diagnostics identify mild decrease in urea, mild elevation in ALT, and marked elevation in pre-and post-prandial bile acids. Which of the following is the most likely differential diagnosis?
a) Copper associated chronic hepatopathy
b) Neutrophilic cholangitis
c) Extrahepatic portosystemic shunt
d) Acquired portosystemic shunt
c) Extrahepatic portosystemic shunt
A 6 month old male Yorkshire Terrier presents with a 2-day history of dull mentation, and episodes of apparent blindness today. Your initial diagnostics identify mild decrease in urea, mild elevation in ALT, and marked elevation in pre-and post-prandial bile acids. Which of the following is the most likely differential diagnosis?
Which of the following medications would be most effective in decreasing the signs of hepatic encephalopathy in the Yorkie puppy from the previous slide?
a) Lactulose
b) Ursodiol
c) Vitamin E
d) Omeprazole
a) Lactulose
TRUE OR FALSE:
Protein restriction should be considered in all dogs and cats with a suspected portosystemic shunt.
false
* Most dogs can have normal protein levels
* Feeding smaller, more frequent meals helps decrease protein load at once,
maintains appropriate calorie/protein nutrition
* Mild and temporary protein restriction might be required – only in severe cases
