Portosystemic Shunts in Dogs – Vocabulary Review

30 vocabulary flashcards summarizing essential terminology and concepts related to canine portosystemic shunts, their diagnosis, clinical signs, and treatment options.

Portosystemic Shunt (PSS)

An abnormal blood vessel that allows portal blood to bypass the liver and enter systemic circulation directly.

Hepatic Encephalopathy

Neurologic dysfunction resulting from the liver’s inability to detoxify ammonia and other metabolites.

Extrahepatic Shunt

A portosystemic shunt located outside the liver parenchyma.

Intrahepatic Shunt

A portosystemic shunt coursing through or within the liver tissue.

Patent Ductus Venosus

The fetal vessel that normally closes after birth but, if it remains open, becomes a congenital intrahepatic shunt.

Congenital Shunt

A portosystemic shunt present at birth due to developmental failure of normal vessel closure.

Acquired Shunt

Collateral vessels that form secondary to chronic liver disease or portal hypertension in adult animals.

Portal Venogram

Contrast radiographic study that visualizes the portal venous system to identify shunts.

Portal Scintigraphy

Nuclear imaging test using radioactive tracers to detect portal blood flow abnormalities and shunts.

Mesenteric Portography

Injection of contrast into mesenteric veins to map the portal circulation on radiographs.

Amyeroid Constrictor Ring

Surgical device placed around a shunting vessel that slowly swells to occlude flow over time.

Surgical Ligation

Direct tying off or gradual occlusion of a shunt vessel to redirect blood through the liver.

Low-Protein Diet

Medical management strategy (≤18 % protein) that reduces ammonia production in patients with hepatic insufficiency.

Intestinal Antibiotics

Drugs used to decrease gut bacteria and limit ammonia production (e.g., metronidazole, neomycin).

Hypoglycemia

Low blood glucose; a metabolic cause of neurologic signs ruled out in this case.

Hyperammonemia

Elevated blood ammonia concentration commonly seen with portosystemic shunts.

Hypoxia

Insufficient oxygen delivery that can cause metabolic encephalopathy.

Prosencephalon (Forebrain)

Brain region whose dysfunction can produce blindness, circling, and disorientation.

Polyuria

Production of abnormally large volumes of urine.

Polydipsia

Excessive thirst with increased water intake.

Alkaline Phosphatase (ALP)

Liver enzyme; elevated levels may indicate hepatic dysfunction.

Serum Albumin (Low)

Reduced blood albumin concentration suggesting impaired hepatic synthesis or loss.

Ammonium Biurate Crystals

Urinary crystals formed when ammonia is elevated; classic in dogs with PSS.

Bile Acids (Elevated)

Increased serum bile acids reflecting decreased hepatic clearance or abnormal portal blood flow.

Caudal Vena Cava

Major systemic vein into which shunting blood may drain, bypassing the liver.

Portal Vein

Vessel carrying nutrient-rich blood from the intestines to the liver under normal conditions.

Yorkshire Terrier Predisposition

Small-breed dogs such as Yorkies have ~35 % risk for congenital PSS.

Postoperative Seizures

Neurologic complication within days after shunt surgery due to metabolic shifts or hypoglycemia.

Portal Hypertension

Increased pressure in the portal venous system; can trigger development of acquired shunts.

Recumbency

Inability or reluctance to stand, noted as a clinical sign in affected puppies.