Section VI. 

 DISEASES OF THE LIVER. 



1. Jaundice. Icterus. 



Etiology. The most frequent cause of jaundice, especially 

 in dogs, is catarrh of the duodenum, with which catarrh of the 

 larger bile ducts (catarrhal jaundice) is often associated. 

 Similarly, jaundice is often a complication of acute gastric ca- 

 tarrh. More rarely, jaundice is caused by impaction of tlie duo- 

 denum and by tumors in the neighborhood of the pylorus (Eber- 

 lein). Occlusion of the bile ducts by foreign bodies, parasites 

 (masses of flukes or roundworms), gallstones, neoplasms and 

 fibrous tissue, prevent the outflow of bile. Compression of the 

 bile duct by enlarged portal Ij^nphatic glands, chronic inflannna- 

 tion around the portal fissure, echinococcus cysts, neoplasms and 

 enlargement of other organs may produce the same effect. The 

 passive hyperemia of the liver in both acute and chronic hepatitis 

 causes jaundice by compression of the smallest bile ducts. 

 (Schmidt observed severe jaundice in a horse as a result of vol- 

 vulus of the left lobe of the liver.) 



Thrombosis, compression of the portal vein, owing either to 

 enlargement of the pancreas or of the portal lJ^nphatic glands, 

 and chronic inflammation of the portal vein are very exceptional 

 causes of jaundice. 



The innnediate cause of the jaundice observed in cases of 

 poisoning by phosphorus, arsenic, salt, lupinose, etc., is to be 

 found in the plugging of the minute primary bile ducts with 

 debris of liver cells. 



Not rarely hemoglobinemia (due to piroplasmosis, extensive 

 burning of the skin, and certain infectious diseases, etc.) is 

 associated with jaundice. In such cases excessive quantities of 

 bile pigment are manufactured liy the liver cells from the ab- 

 normally large amount of lilood pigment that is present in solu- 

 tion in the blood plasma (pleiochromia), while there is not a pro- 

 portional production of the fluid constituents of the bile. The 

 l)ile produced under these circumstances is viscid and is with 

 difficulty passed out of the liver, consequently a portion is re- 

 absorbed. 



The form of jaundice that sometimes occurs during attacks 



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