Hepatic Vascular Anomalies Chapter 284
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Questions and Answers

What is the normal pathway of blood flow from the spleen, small intestines, pancreas, and stomach?

  • Portal vein to hepatic sinusoids to caudal vena cava (correct)
  • Systemic circulation to portal vein to hepatic sinusoids
  • Hepatic sinusoids to portal vein to caudal vena cava
  • Caudal vena cava to portal vein to hepatic sinusoids

    • What is the function of the ductus venosus in the fetal liver?

  • To increase oxygenation of the liver
  • To bypass hepatic circulation and direct blood to the caudal vena cava (correct)
  • To decrease blood flow to the liver
  • To increase hepatic metabolism and detoxification

    • What is the result if the ductus venosus remains patent after birth?

  • Portosystemic shunt (correct)
  • Decreased hepatic function
  • Patent subhepatic shunt
  • Increased hepatic function

    • What is the clinical sign associated with the origin of blood bypassing the liver in PSS?

    <p>All of the above</p> Signup and view all the answers

    How does the portal vein branch in the dog?

    <p>Into right and left branches</p> Signup and view all the answers

    Where do the portal vein branches eventually empty into?

    <p>Caudal vena cava</p> Signup and view all the answers

    What is the most common type of portosystemic shunt?

    <p>Extrahepatic shunt with a single portocaval shunt</p> Signup and view all the answers

    Which breed of dog is more commonly associated with intrahepatic portosystemic shunts (IHPSS)?

    <p>Large breed dogs</p> Signup and view all the answers

    What is the role of bile acids in the small intestine?

    <p>Aid in lipid absorption via intestinal fat emulsification and metabolism</p> Signup and view all the answers

    What is the significance of elevated postprandial bile acids in dogs and cats?

    <p>Indicates PSS in 100% of cases</p> Signup and view all the answers

    What is the cause of persistent bile acid concentration elevations in animals with PSS?

    <p>Shunting of reabsorbed SBA to the systemic circulation</p> Signup and view all the answers

    What is the purpose of measuring 6-hour postprandial blood ammonia concentrations?

    <p>To increase detection sensitivity of PSS</p> Signup and view all the answers

    What is the typical characteristic of ascites in animals with PSS?

    <p>Pure transudate with protein content &lt; 2.5 g/dl and cells &lt; 1000/ul</p> Signup and view all the answers

    What is the common coagulation abnormality in dogs with PSS?

    <p>Prolonged PTT only</p> Signup and view all the answers

    What is the typical ultrasound finding in animals with EHPSS?

    <p>Small liver</p> Signup and view all the answers

    What is the gold standard for PSS diagnosis?

    <p>CT angiography</p> Signup and view all the answers

    What is the significance of protein C levels in differentiating between PSS and MVD?

    <p>Protein C levels are high in MVD and low in PSS</p> Signup and view all the answers

    What is the typical histopathological finding in the liver of animals with PSS?

    <p>Microscopic bile duct proliferation and hypoplasia of intrahepatic portal tributaries</p> Signup and view all the answers

    What is the typical history of dogs with PSS?

    <p>Failure to thrive</p> Signup and view all the answers

    Which breed is overrepresented for MVD/PVH?

    <p>Yorkie</p> Signup and view all the answers

    What is the common cause of ascites in HAVM?

    <p>Portal hypertension</p> Signup and view all the answers

    What is the common complication of PSS in large breed dogs?

    <p>GI hemorrhage</p> Signup and view all the answers

    What is the result of defective iron transport mechanism in dogs with PSS?

    <p>Microcytic, normochromic anemia</p> Signup and view all the answers

    What is the common finding in dogs with PSS?

    <p>Leukocytosis</p> Signup and view all the answers

    What is the result of deficient hepatic urea cycle in dogs with PSS?

    <p>Hyperammonemia</p> Signup and view all the answers

    What is the common site of stones formation in dogs with PSS?

    <p>Kidney</p> Signup and view all the answers

    What is the common feature of animals with PVH/MVD?

    <p>Present late and are less affected</p> Signup and view all the answers

    What is the reason portovenography during laparotomy is not commonly utilized?

    <p>It is invasive and requires fluoroscopy</p> Signup and view all the answers

    What is the main goal of medical management in dogs with HE?

    <p>To quickly lower ammonia levels</p> Signup and view all the answers

    What is the effect of lactulose administration in dogs with HE?

    <p>It acidifies colonic content, trapping ammonia as ammonium</p> Signup and view all the answers

    Why is Supplement K administration important in dogs with HE?

    <p>To correct hypokalemia</p> Signup and view all the answers

    What is the purpose of antibiotic therapy in dogs with HE?

    <p>To reduce bacterial proliferation</p> Signup and view all the answers

    What is the benefit of using milk and vegetable proteins in dogs with HE?

    <p>They have fewer aromatic amino acids</p> Signup and view all the answers

    What is the role of SAMe in medical management of dogs with HE?

    <p>It has hepatoprotective, antioxidant, and antiinflammatory properties</p> Signup and view all the answers

    What is the goal of surgical management in dogs with PSS?

    <p>To promote portal perfusion and reestablish blood flow through hepatic parenchyma</p> Signup and view all the answers

    What is a potential complication of complete shunt attenuation?

    <p>Portal hypertension</p> Signup and view all the answers

    What is the reported survival time in dogs with IHPSS medically managed?

    <p>9.9 months</p> Signup and view all the answers

    What is the reported complication rate following ameroid constrictor placement for EHPSS?

    <p>7-20%</p> Signup and view all the answers

    What is a potential benefit of using ameroid constrictors compared to suture ligation?

    <p>Reduced surgery times and intraoperative complication rates</p> Signup and view all the answers

    What is a characteristic of cellophane band material?

    <p>It is inflammatory and causes progressive fibrosis around vessels</p> Signup and view all the answers

    What is a potential complication of IHPSS in dogs?

    <p>All of the above</p> Signup and view all the answers

    What is a reported outcome in dogs with incomplete shunt attenuation after ameroid constrictor placement?

    <p>Good to excellent outcomes in 94% of dogs</p> Signup and view all the answers

    What is a characteristic of HAVM?

    <p>Chronic portal hypertension</p> Signup and view all the answers

    What is a goal of post-operative care?

    <p>To keep the patient calm and reduce portal hypertension</p> Signup and view all the answers

    What is a reported outcome in cats following suture ligation for PSS?

    <p>Fair to excellent outcomes in 75% of cats</p> Signup and view all the answers

    What is a potential treatment for HAVM?

    <p>All of the above</p> Signup and view all the answers

    What is a reported median survival time in dogs following ameroid constrictor placement for EHPSS?

    <p>152 months</p> Signup and view all the answers

    Study Notes

    Hepatic Vascular Anomalies

    Introduction

    • Hepatic vascular anomalies, such as portosystemic shunts (PSS), connect the portal vein to the systemic circulation, bypassing the hepatic sinusoids.
    • Normally, blood from the spleen, small intestines, pancreas, and stomach enters the portal vein, perfuses the liver through the sinusoids, and then drains into the hepatic veins and caudal vena cava.

    Anatomy and Classification

    • Blood from the GI tract, pancreas, and spleen is drained by respective veins, which empty into the portal vein.
    • In dogs, the portal vein enters the liver and branches into left and right branches.
    • In cats, there are central, right, and left branches of the portal vein.
    • PSS can be classified as congenital intrahepatic or congenital extrahepatic shunts.
    • Congenital extrahepatic PSS with a single portocaval shunt are most common (66-75% of shunts).

    Clinical Signs

    • Clinical signs associated with volume and origin of blood bypassing the liver, including:
      • Impaired hepatic function
      • Hepatic encephalopathy (HE)
      • Chronic GI signs
      • Lower urinary signs if stones form
      • Coagulopathies
      • Delayed growth

    Hepatic Encephalopathy (HE)

    • Most clinical signs seen with PSS are due to HE.
    • HE is caused by the inability of the liver to detoxify ammonia and other toxins.

    Evaluation

    • Congenital EHPSS are more common in small breeds, such as Yorkies, Pugs, and Havanese.
    • IHPSS are more common in large breeds, such as Labradors, Wolfhounds, and Golden Retrievers.
    • Common symptoms:
      • Failure to thrive
      • Polyuria and polydipsia (PU/PD)
      • Bizarre behavior due to HE
      • GI signs
      • Dysuria due to ammonium urate calculi formation
      • Ascites in HAVM cases

    Clinicopathologic Findings

    • Mild to moderate microcytic, normochromic nonregenerative anemia
    • Leukocytosis associated with poor clearance of bacterial endotoxin
    • Low albumin and BUN levels
    • Hypocholesterolemia
    • Hypoglycemia
    • Elevated ALP and ALT levels
    • Hyposthenuric or isosthenuric urine and ammonium biurate crystalluria

    Liver Function Tests

    • 12-hour fasting and 2-hour postprandial bile acids
    • Bile acid levels aid in diagnosing PSS.

    Treatment

    • Medical management:
      • Manage HE with lactulose, oral antibiotics, and protein restriction
      • Correct coagulopathies and hypoglycemia
      • Supplement potassium and vitamin K
    • Surgical management:
      • Attenuate the abnormal vessel to reestablish blood flow through the hepatic parenchyma
      • Goal is to improve clinical signs and control HE
      • Surgery may not be possible in all cases, and medical management may be necessary

    Prognosis

    • Prognosis is dependent on the type of shunt, severity of clinical signs, and response to treatment.
    • In some cases, medical management alone can lead to a good prognosis.
    • Surgery can improve outcomes, but complications can occur.

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    Quiz Team

    Description

    This quiz covers hepatic vascular anomalies, specifically portosystemic shunts (PSS) and their connection to the portal vein and systemic circulation. It also touches on the fetal liver's limited capacity for metabolism and detoxification.

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