Veterinary Clinical Medicine-I (General and Systemic)

PORTOSYSTEMIC SHUNTS

• Congenital or acquired. Blood from intestinal tract diverted around hepatic parenchyma and enters systemic circulation via azygos or caudal vena cava without undergoing hepatic metabolism.
• Most common shunts are single intrahepatic (large breed) or extrahepatic shunts (small breed). Yorkies are predisposed.

Clinical signs

• Hepatic encephalopathy. Worsen just after meal.
• Impaired liver function.
• Slow to wake up from anesthesia.

Diagnosis

• Increased bile acids (do pre and post),
• Increased uric acid.
• Uric acid calculus in non-dalmation suggestive of liver shunt.
• Cranial mesenteric arteriography or splenoportography.
• Ultrasound.

Treatment

• Surgical correction, unless acquired (then compensating for failed liver – fixing would cause deterioration).

• Medical management of hepatic encephalopathy includes low-protein diet (to lower protein levels and subsequent metabolic ammonium load), lactulose, enteric antibiotics (to prevent colonic ammonium production and systemic absorption) such as oral neomycin.