132 SWINE PRACTICE 



HYPEREMIA 



Hyperemia of the liver may be physiologic or pathologic. Physio- 

 logic hepatic hyperemia occurs after eating and is of no significance 

 economically or pathologically. Pathologic hepatic hyperemia may 

 be either venous (passive) or arterial (active). 



Passive hepatic hyperemda is caused by obstructed outflow of blood. 

 Cardiac defects of the valves of the right side of the heart are a 

 potent cause. Obstruction of the posterior vena cava or the hepatic 

 vein by new growths, abscesses, and cicatricial tissue will also pro- 

 duce venous engorgement of the liver. 



Lesions. — A careful examination will disclose the lesion producing 

 the engorgement as well as the engorged condition of the liver. The 

 liver will be full of blood and of a slightly darker color than nor- 

 mal. If the condition becomes chronic there will be fibrous pro- 

 liferation. 



Symptoms. — The signs of venous hepatic hyperemia vary according 

 to the intensity of the condition and its duration. The animals be- 

 come dull, and there is only a sluggish action of the bowels. If the 

 condition progresses until there is fibrous proliferation, disturbances 

 of nutrition become evident. 



Arterial hepatic hyperemia may be the result of involvement of the 

 hepatic artery or of the portal vein. This is a condition character- 

 ized by an increased inflow of blood into the liver. Hyperemia of 

 the hepatic artery is not common, and when it does occur it is 

 usually chronic. This condition is usually the result of partial 

 occlusion of the gastric or splenic branches of the celiac axis, al- 

 though it may be caused by some irritation in the terminal vessels 

 in the hepatic interstitial tissue. No definite symptoms are evi- 

 denced, and the value of treatment is doubtful. 



Portal hepatic hyperemia is usually caused by tainted foods or by 

 infection. The liver may be increased fifty per cent in volume, and 

 becomes gorged with blood. The symptoms are obscure. Some re- 

 lief may be obtained by the free use of laxatives. 



Treatment. — The removal of the cause, if that be possible, is about 

 all that can be accomplished. 



HEPATITIS 



Inflammation of the liver, or hepatitis, is rather common in swine. 

 The condition may assume either an acute or chronic form. 



