| 英文描述 | Portosystemic anastomoses or shunts can occur in dogs and cats, allowing venous blood to bypass the liver. Most common in young animals. In portosystemic shunts, vascular communications between the portal and systemic venous systems allow bypass of the liver. Hepatic microvascular dysplasia has been described in dogs; small intrahepatic portal vessels and portal endothelial hyperplasia allows communication between portal and systemic circulation. Hepatic microvascular dysplasia can be an isolated disease or can be present in conjunction with portosystemic shunts. The presenting signs may be primarily related to the digestive tract, or there may be signs of neurologic disease due to hepatoencephalopathy. Hyperammonemia, ammonium biurate crytalluria, and bile acid elevation can occur. Diagnosis confirmed by contrast venography, although in hepatic microvascular dysplasia biopsy is required for diagnosis. A syndrome resembling idiopathic noncirrhotic portal hypertension has been reported in Doberman Pinschers; these dogs lacked intrahepatic arteriovenous fistulae, portal vein atresia, or intrahepatic fibrosis. Uric acid stones associated with shunts can cause signs of bladder disease. |
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