Portosystemic Shunts

anomalous communication(s) b/w the portal and systemic venous system where portal blood is directly shunted into the systemic circulation bypassing the liver

portosystemic shunt

PSS characterizations?

Congenital vs. acquired

Extra vs. intrahepatic

Single vs. multiple

Portal vein hypoplasia (aka microvascular dysplasia

are congenital shunts generally single or multiple?

single

are acquired shunts generally single or multiple?

multiple

clinical signs of PSS?

Forebrain neuro signs (often post-prandial)

Urinary tract signs

GI signs

Non-specific poor doers

hepatic encephalopathy results from accumulation of ? due to PSS

ammonia

mercaptans

aromatic AA

benzo-like substances

GABA

glutamine, glutamate

what vessel supplies 80% of. the total blood flow to the liver?

portal vein

with PSS, ammonia accumulates becuase the liver is not converting it into

urea

parameters of liver dysfunction?

hypoproteinemia (albumin, globulins, clotting factors)

hypoglycemia

low BUN

hypocholesterolemia

(think GUAC)

hyperbilirubinemia

small breed dogs are prone to what kind of shunts?

congenital extrahepatic

large breed dogs are prone to what kind of shunts?

congenital intrahepatic

TF cats are equally prone to congenital extra and intrahepatic shunts

T

first line liver function test?

pre and post prandial bile acids assay (typically >100umol/L)

goal of shunt medical management?

Correct electrolytes with supportive care

Decrease bacterial byproduct "toxin" absorption

how can we decrease bacterial GI "toxin" absorption and therefore, medically manage PSS?

Protein restricted diet

PO antibiotics to decrease colonic bacteria (e.g. metro)

Lactulose

gold standard for PSS dx?

CT angiography

gold standard tx for congenital shunts?

surgery

TF portosystemic shunt patients should be medically managed to resolve clinical signs prior to surgery

T

TF acute complete ligation is the gold standard surgical procedure for portosystemic shunts

F

often leads

acute complete ligation often leads to ? due to poorly developed intrahepatic portal systems in congenital PSS patients

portal hypertension

Gradual occlusion surgical methods for portosystemic shunts?

Partial silk ligation

Ameroid constrictors

Cellophane banding

Hydraulic occluders

Early complications of gradual attenuation PSS procedures?

Post Attenuation Neurologic Syndrome

Portal hypertension

Hemorrhage

DIC

Death

early complication of gradual attenuation PSS procedures that occurs in 5-7% of patients resulting in a 5x greater risk of mortality with seizures

Post Attenuation Neurologic Syndrome (PANS)

Late complications of gradual attenuation PSS procedures?

Persistent shunting

Incomplete closure

Acquired shunts

Liver failure

monitoring tool that can be used to assess success of gradual attenuation PSS procedures?

bile acid profiles

light blue

which line indicates what happens if the gradual attenuation PSS procedure is successful?

dark blue

which line indicates what happens if the gradual attenuation PSS procedure fails?

gray

which line indicates what happens if there is portal hypertension and acquired shunts following a gradual attenuation PSS procedure ?

prognosis for dogs with a single congenital PSS treated by gradual occlusion?

good to excellent

prognosis for cats with a single congenital PSS treated by gradual occlusion?

fair to good but more unpredictable