96. Hepatic Vascular Anomalies Flashcards
What is the primary function of the portal vein in the liver?
To supply 75% to 80% of the afferent blood volume and 50% of the oxygen supply to the liver.
Name two clinical signs associated with hepatic encephalopathy in dogs.
Seizures and ataxia.
What is the main blood vessel supplying oxygenated blood to the liver apart from the portal vein?
Hepatic artery.
What type of portosystemic shunt is most common in small or toy breed dogs?
Extrahepatic portosystemic shunt.
What congenital vascular anomaly is characterized by multiple arterial and venous communications within the liver?
Hepatic arteriovenous malformation.
Which vein in dogs typically divides into right and left branches 0.5 to 1.0 cm beyond its gastroduodenal tributary?
Portal vein.
What condition is characterized by small intrahepatic portal vessels and may be accompanied by fibrosis?
Primary hypoplasia of the portal vein without portal hypertension (previously known as microvascular dysplasia).
What is the major neurotoxic substance thought to play a role in hepatic encephalopathy?
Ammonia.
In dogs with congenital portosystemic shunt (PSS), which breed has the highest reported odds ratio for this condition?
Yorkshire Terrier.
Which dietary adjustment is recommended to manage hepatic encephalopathy in dogs with PSS?
Protein restriction with high-quality protein sources, such as milk or vegetable protein.
What imaging modality is considered the gold standard for evaluating the portal venous system in humans?
Computed tomographic angiography.
Name a condition that commonly presents with similar signs to hepatic vascular anomalies in small breed dogs.
Toy-breed hypoglycemia.
What is the purpose of bile acids in liver function tests for animals with PSS?
To evaluate liver function by measuring the liver’s ability to process and recirculate bile acids.
What breed is associated with intrahepatic portosystemic shunt (PSS) in large dogs?
Irish Wolfhound.
What enzyme’s activity is often measured to differentiate between PSS and portal vein hypoplasia without portal hypertension?
Protein C.
What is a common histologic finding in dogs with congenital PSS?
Bile duct proliferation and hypoplasia of intrahepatic portal tributaries.
Name one clinical sign specific to cats with congenital PSS.
Ptyalism (excessive salivation).
Which vein in the liver receives blood from the papillary process of the caudate lobe in dogs?
Left portal vein.
What imaging technique uses technetium for detection of portosystemic shunts?
Nuclear scintigraphy.
Name the blood test most commonly used to screen for liver dysfunction in animals with hepatic vascular anomalies.
Serum bile acids test.
What is the cause of microcytic anemia often seen in dogs with PSS?
Hypoferremia.
Which condition in dogs may present with signs of urolithiasis due to ammonium urate crystalluria?
Congenital portosystemic shunt.
What medical therapy is often used to reduce ammonia levels in hepatic encephalopathy?
Lactulose.
Name a coagulation disorder common in dogs with PSS.
Prolonged prothrombin time (PT).
What type of biopsy is often recommended at the time of congenital shunt attenuation if liver enzyme values are elevated?
Liver biopsy.
Which artery supplies the caudate and right lateral hepatic lobes in dogs?
Right lateral branch of the hepatic artery.
What is the most common location for extrahepatic PSS to terminate?
Caudal vena cava or azygos vein.
What vitamin deficiency is commonly associated with coagulation issues in liver disease?
Vitamin K deficiency.
In what percentage of dogs with congenital PSS are ammonium urate crystals reported?
26% to 57%.
Which imaging technique is useful for detecting radiolucent uroliths in dogs and cats with hepatic vascular anomalies?
Ultrasonography.
Which diet is found beneficial for dogs with hepatic encephalopathy, soy-based or meat-based?
Soy-based diet.
What histologic change is common in cats with congenital PSS?
Portal vein hypoplasia.
Name an antioxidant commonly used as a liver supportive therapy for animals with hepatic vascular anomalies.
S-adenosyl-methionine (SAMe).
What breed is prone to developing hepatic arteriovenous malformations?
No specific breed, it can occur in any breed.
Which nerve supplies the lips and cheeks in dogs?
Facial nerve (CN VII).
What is the typical survival time for dogs with PSS managed medically without surgery?
Median survival time is approximately 9.9 months.
What type of anemia is commonly seen in animals with PSS?
Microcytic anemia.
What is the primary effect of protein C deficiency in animals with liver disease?
Increased risk of thrombosis.
What is the effect of excessive bile acid concentrations in animals with PSS?
Bile acids enter the systemic circulation, reflecting liver dysfunction.
Which amino acid imbalance is associated with hepatic encephalopathy?
Increased aromatic amino acids and decreased branched-chain amino acids.
What is the role of endothelin in the ductus venosus closure?
It promotes contraction of the ductus venosus in response to reduced blood flow.
In which breed is the ductus venosus closure delayed compared to others?
Irish Wolfhound.
Which laboratory finding is typical in dogs with congenital PSS?
Hypoalbuminemia.
Name a neurotransmitter involved in hepatic encephalopathy due to ammonia toxicity.
Glutamate.
What enzyme is primarily involved in the detoxification of ammonia in the liver?
Urea cycle enzymes (e.g., ornithine transcarbamylase).
Which imaging modality allows a detailed 3D image of the liver vasculature?
Magnetic resonance angiography (MRA).
What treatment is recommended for severe hypoalbuminemia in small dogs with PSS?
Administration of plasma or human serum albumin.
Name one breed overrepresented with extrahepatic PSS in cats.
Domestic shorthairs.
Which condition can lead to glomerulosclerosis secondary to hepatic vascular anomalies?
Immune-mediated glomerulonephritis due to antigen accumulation.
What is the typical response in blood ammonia levels after surgical attenuation of a congenital PSS?
Decrease in blood ammonia levels.
Which type of portosystemic shunt is most commonly seen in small or toy breed dogs? A) Intrahepatic PSS B) Extrahepatic PSS C) Acquired PSS D) Hepatic Arteriovenous Malformation
B) Extrahepatic PSS
What is the primary source of blood ammonia in animals with hepatic encephalopathy? A) Muscle tissue B) Liver C) Kidneys D) Gastrointestinal tract
D) Gastrointestinal tract
Which breed is most commonly associated with congenital portosystemic shunts? A) Labrador Retriever B) German Shepherd C) Yorkshire Terrier D) Golden Retriever
C) Yorkshire Terrier
What percentage of blood volume to the liver is supplied by the portal vein? A) 50% B) 60% C) 70% D) 75%-80%
D) 75%-80%
What condition is characterized by excessive ammonia in the bloodstream due to reduced liver function? A) Hepatic fibrosis B) Hepatic encephalopathy C) Portal vein hypoplasia D) Hepatic neoplasia
B) Hepatic encephalopathy
Which imaging modality is preferred for detailed pre-surgical planning of hepatic vascular anomalies? A) Radiography B) Ultrasound C) Computed Tomographic Angiography D) Scintigraphy
C) Computed Tomographic Angiography
In dogs, which liver lobe is primarily supplied by the right lateral branch of the hepatic artery? A) Right lateral lobe B) Left medial lobe C) Quadrate lobe D) Left lateral lobe
A) Right lateral lobe
Which factor is often considered the primary neurotoxic substance in hepatic encephalopathy? A) Ammonia B) GABA C) Glutamine D) Bilirubin
A) Ammonia
Which hepatic vein is typically the largest and most cranial in dogs? A) Caudate vein B) Right hepatic vein C) Left hepatic vein D) Central vein
C) Left hepatic vein
What is a common clinical finding in cats with congenital portosystemic shunts? A) Hypertension B) Ptyalism C) Polydipsia D) Ascites
B) Ptyalism
What is the typical urine specific gravity finding in dogs with congenital PSS? A) Hyposthenuric B) Hypersthenuric C) Isosthenuric D) Hypertonic
A) Hyposthenuric
Which abnormality is most commonly seen on abdominal radiographs of dogs with PSS? A) Hepatomegaly B) Splenomegaly C) Microhepatia D) Renal atrophy
C) Microhepatia
What blood test is most commonly used to evaluate liver function in animals with PSS? A) Ammonia concentration B) ALT C) Bile acids D) Albumin levels
C) Bile acids
Which type of PSS is most commonly associated with larger dog breeds? A) Extrahepatic PSS B) Intrahepatic PSS C) Portal hypoplasia D) Acquired PSS
B) Intrahepatic PSS
Which enzyme is typically increased in dogs with portosystemic shunts? A) ALT B) AST C) Amylase D) Lipase
A) ALT
In dogs with congenital PSS, low concentrations of which substance are commonly noted? A) Glucose B) Urea C) Bile D) Bilirubin
B) Urea
Which breed is overrepresented in cases of primary hypoplasia of the portal vein without portal hypertension? A) Doberman Pinscher B) Golden Retriever C) Cairn Terrier D) Maltese
C) Cairn Terrier
What is a common histopathologic finding in dogs with congenital PSS? A) Necrosis B) Hyperplasia of arterioles C) Thrombosis D) Lymphoid hyperplasia
B) Hyperplasia of arterioles
Which venous system contributes to the formation of the portal vein during embryologic development? A) Cardinal veins B) Subcardinal veins C) Umbilical veins D) Vitelline veins
D) Vitelline veins
Which diagnostic test is contraindicated in animals with baseline elevated ammonia? A) Bile acids test B) Protein C test C) Liver biopsy D) Ammonia tolerance test
D) Ammonia tolerance test
Which artery provides blood to the left lateral and medial liver lobes in dogs? A) Right lateral branch B) Hepatic artery C) Left hepatic artery D) Left portal vein
C) Left hepatic artery
What is the major anatomical effect of hepatic arteriovenous malformations? A) Fibrosis of hepatic veins B) Hepatofugal blood flow C) Hyperplasia of Kupffer cells D) Portal vein thrombosis
B) Hepatofugal blood flow
What percentage of afferent blood supply to the liver is provided by the portal vein? A) 50-55% B) 60-65% C) 75-80% D) 85-90%
C) 75-80%
Which breed of dog is most likely to present with congenital portosystemic shunts? A) Golden Retriever B) Yorkshire Terrier C) Labrador Retriever D) Beagle
B) Yorkshire Terrier
What is the primary clinical sign associated with hepatic encephalopathy? A) Gastrointestinal signs B) Neurologic abnormalities C) Respiratory distress D) Cardiac arrhythmias
B) Neurologic abnormalities
Which vein is the largest tributary of the portal vein in dogs? A) Splenic vein B) Gastroduodenal vein C) Cranial mesenteric vein D) Caudal mesenteric vein
C) Cranial mesenteric vein
What is the most common type of congenital portosystemic shunt in small breed dogs? A) Extrahepatic shunt B) Intrahepatic shunt C) Portoazygos shunt D) Arteriovenous malformation
A) Extrahepatic shunt
In which species does the portal vein divide into right, central, and left branches? A) Dogs B) Cats C) Horses D) Pigs
B) Cats
Which liver lobe is primarily supplied by the right portal vein in dogs? A) Left medial lobe B) Quadrate lobe C) Right lateral lobe D) Caudate lobe
C) Right lateral lobe