Portosystemic Shunt

Portosystemic Shunt



Basic Information image



Definition


Portosystemic shunts are vascular anomalies that cause blood from the portal circulation to bypass the liver and flow into the systemic circulation, allowing metabolic byproducts that are normally removed and detoxified by the liver to accumulate in the circulation. Portosystemic shunts can be either intrahepatic or extrahepatic and congenital or acquired.



Epidemiology



Species, Age, Sex


Although rare, congenital extrahepatic shunts are most commonly reported in foals younger than 6 months.



Associated Conditions and Disorders


Clinical signs of a portosystemic shunt may be indistinguishable from other liver diseases causing hepatic encephalopathy.



Clinical Presentation



Disease Forms/Subtypes


Portosystemic shunts may be congenital or acquired and intrahepatic or extrahepatic.



History, Chief Complaint


Nonspecific clinical signs include vague to obvious intermittent to persistent neurologic deficits (blindness, depression, head pressing, ataxia), decreased appetite, failure to thrive, colic, icterus, and fever.



Physical Exam Findings


Physical examination findings are nonspecific and include neurologic deficits associated with hepatic encephalopathy (variable to profound depression, cerebral blindness, ataxia), fever, icterus, poor body condition, and abdominal pain.



Etiology and Pathophysiology




• Clinical signs and clinicopathologic abnormalities are the result of altered blood flow from the portal vein around or through the liver resulting in accumulation of metabolic by-products, such as ammonia, that circumvent detoxification by the liver and thus accumulate in the systemic circulation.


• Aberrant hepatic blood flow may also contribute to hepatic atrophy.



Diagnosis image



Differential Diagnosis




• Any liver disease causing signs of hepatic encephalopathy


• Biliary obstruction in foals secondary to duodenal stricture


• Biliary atresia


• Liver abscesses


• Cirrhosis


• Cholangiohepatitis


• Cholangitis


• Hepatic neoplasia (metastatic lymphoma)


• Other diseases causing weight loss

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Jul 24, 2016 | Posted by in SMALL ANIMAL | Comments Off on Portosystemic Shunt

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