310 Patliogenesis. Anatomical Changes. Symptoms. 



Since the muscularis of the stomach becomes weakened with 

 advancing age and since mastication likewise becomes deficient, 

 chronic gastric dilatation is frequentlj^ seen in older animals. 



Pathogenesis. Most of the causes enumerated first pro- 

 duce hypertrophy of the gastric muscularis which enaljles the 

 stomach to furnish the required increased amount of work. 

 After the ingestion of food, particularly in horses, the stomach 

 is stimulated to stronger even to convulsive contractions, which 

 have the object to propel the gastric contents into the intestines. 

 It is possible that the stomach gets rid of its contents in this 

 manner, though after a considerable time. By and by the mus- 

 cular power decreases, the food remains longer in the stomach, 

 it ferments and the stomach l)ecomes more and more dilated. 

 According to its size the dilated stomach forms an impediment 

 to respiration and influences the blood circulation unfavorably, 

 especially when it is filled with food stuffs. The disturbances 

 are most marked right after the ingestion of food and they may 

 amount to pain. As the dilatation increases, the muscularis of 

 the stomach finally loses its contractility completely and the 

 gastric contents cannot be removed any more. 



Anatomical Changes. The stomach is sometimes increased 

 to several times its normal size, and in grave cases its shape 

 may also be changed (the stomach of the horse becomes egg- 

 shaped or similar in shape to the rumen of cattle), its wall is 

 generally thickened, occasionally also thinned, sometimes as thin 

 as brown paper (Fitzroy-Philipot), sometimes also fairly tough 

 (Lienaux). The mucosa generally presents the signs of chronic 

 catarrh. Sometimes we find as the cause of a dilatation a tumor 

 in the stomach, in the pylorus or in the intestines. 



In a case of Koch, the stomach of a horse weighed 51 kilograms when full 

 and had a cubic content of 84 liters (the normal cubic contents being 7 to 15 

 liters) ; its largest diameter was 164 cm. Fitzroy-Philipot found a full stomach 

 of a horse weighing 71 kg., it weighed 10 kg. (about 20 pounds) when empty and 

 its length (between cardia and pylorus was 261 cm., the greatest thickness 190 cm. 

 Lienaux found the larger curvature in an adult setter dog to be -50 cm. long. 

 However, increases of this extreme degree are seen only exceptionally. 



Symptoms. Horses suffer in this affection frequently from 

 repeated attacks of colic (socalled chronic or periodic colic) 

 which are much like those seen in acute dilatation (see page 

 299). Such attacks occur in stenosis of the pylorus almost reg- 

 ularly towards the end of feeding or immediately after it; in 

 other cases shortly after the meal ; they frequently last for sev- 

 eral hours. Each attack may, of course, become fatal in conse- 

 quence of suffocation, rupture of the stomach, etc. In the fur- 

 ther course of the disease the attacks of pain become less severe ; 

 however, the general condition does not improve and the attacks 

 last a longer time; the animals suffer more and more in their 

 general condition. Respiration is also difficult in the periods 



