PORTAL-HYPERTENSION ASSOCIATED WITH PRIMARY HYPOPLASIA OF THE HEPATICPORTAL-VEIN IN DOGS

Portal hypertension caused by primary hypoplasia of the portal vein wa s diagnosed in 42 dogs, The portal hypertension was manifested by the presence of multiple portosystemic collateral vessels. The main clinic al signs were retarded growth or weight loss, apathy, intermittent dia rrhoea and vomiting, anorexia, abdominal distension and polydipsia. Ma jor findings at physical examination were ascites in 23 dogs and neuro logical signs in 16 dogs, The dogs had increased activities of liver e nzymes in plasma and increased fasting levels of total bile acids and ammonia; in many of the dogs the packed red cell volume, total serum p rotein and albumin were low, Gross inspection of the portal vein revea led a patent but underdeveloped extrahepatic vein in 13 of the dogs, M icroscopic examination of the liver revealed hypoplasia of the intrahe patic portal veins in all the dogs, and this was associated with minor arteriolar proliferation and absence of fibrosis in 12 of them, with moderate to marked arteriolar proliferation often combined with ductul ar proliferation in 13, and with marked portal fibrosis (formerly desc ribed as hepatoportal fibrosis) with a varying number of arteriolar an d bile ductular structures in 17 of the dogs, The disease affected mai nly young dogs, and was most likely to have been of congenital origin.