PSS Flashcards
What is a portosystemic shunt?
Abnormality in blood flow that results in deviation of blood from the liver into systemic circulation
What type of shunts make up the majority of PSS?
Singe. congenital, extrahepatic
How much of its blood flow does the liver receive from portal circulation for detoxification?
2/3 of its blood flow
What vessels are shunts usually associated with?
Portal, left gastric, or splenic vein
If shunted blood doesn’t drain into portal circulation, which other vessels do they drain into?
Caudal vena cava or azygous vein
What is the typical signalment for a congenital extrahepatic PSS?
Small breed usually <1yo
What is the poster child for congenital extrahepatic PSS?
Yorkies
What size breeds have a higher likelihood of an intrahepatic shunt?
Large breeds
What is a classic PSS clinical sign in cats?
Copper colored iris
Why do neuro signs accompany PSS?
Hepatic encephalopathy d/t high ammonia levels
What are neuro signs assoc. w/PSS and when do they typically occur?
Head pressing or star gazing, esp after eating
How are bile acids affected by a PSS?
Dramatically high post-prandial bile acids should make you highly suspicious of a PSS
Are ammonia or bile acid tests more sensitive for dx PSS?
Ammonia, but must measure immediately after blood draw (and analyzers are not widely available)
What might you see on a PSS urinalysis?
Ammonium biurate crystals
How will the liver appear on radiographs?
Microhepatia
Can you usually see aberrant vessels on ultrasound of a PSS?
Only 60% of the time
What type of bladder stones are assoc. w/PSS?
Urate
How can you medically manage a PSS?
Metronidazole, lactulose, low-protein diet
Decreases urease-producing bacteria in the colon
Metronidazole
Decreases colonic pH, which results in decreased ammonia absorption
Lactulose
What can you give for a PSS that is seizuring?
KBr
What are surgical options for a PSS?
Ameroid constrictor, cellophane band, or partial/complete ligation
What is the most commonly used PSS closure technique?
Ameroid constrictor
Which surgical technique causes higher portal hypertension and higher complication rates than the others?
Partial/complete ligation
What does post-op pain indicate in a PSS patient?
Complete vessel occlusion and life-threatening portal hypertension
Shunting at the level of the hepatocyte
Microvascular dysplasia
Why must you always take a liver biopsy when surgically correcting a PSS?
Rule in or out microvascular dysplasia
How will presence of microvascular dysplasia influence your treatment post-op?
Presence will indicate long-term medical therapy is also needed
What are clinical signs of a PSS in cats?
Pytalism, copper iris (pathognomonic)
What are the only veins that should enter the vena cava between the hepatic and renal veins?
Phrenicoabdominal veins
How much protein should you feed a PSS?
The maximum amount they will tolerate w/o showing encephalopathy signs
