The acute form is generally due to the irritation of certain substances taken into the stomach and is commonly found at the pyloric end. The mucosa is red, thickened, and covered by mucous secretion, and punctate hemorrhages are occasionally present. Microscopically the epithelial cells are found to be the seat of cloudy swelling, numerous goblet cells are present, and there is an infiltration of round cells. There may be considerable desquamation of the surface epithelium. The lymph follicles are also frequently hyperplastic.

Pseudo-Membranous Gastritis

Pseudo-Membranous Gastritis may be due to the action of caustic substances or to some of the infectious fevers, as smallpox and scarlatina. It may also be the result of the extension of a true diphtheritic process. The mucosa is covered by patches of a grayish-white pseudo-membrane under which the necrotic process may have involved the entire mucosa.

Phlegmonous Gastritis

Phlegmonous Gastritis is very rare, but sometimes follows the entrance of streptococci. The submucosa and muscularis become swollen and infiltrated by pus cells even to the extent of more or less circumscribed abscesses. These may finally rupture into the cavity of the stomach. Healing takes place by the extension of the epithelium from the neighboring tissues into the opening resulting from the rupture of the abscess.

Chronic Gastritis

Chronic Gastritis may be the result of repeated acute attacks or it may have been chronic in form from the onset. It follows the abuse of alcohol, results from the eating of too much or improper food, and occurs also in the course of various constitutional diseases. Chronic congestion predisposes, as in cirrhosis of the liver, heart disease and certain lung affections. In the simple chronic variety the mucosa is thickened, hyperplastic, and infiltrated, and bands of connective tissue surround projecting areas of epithelium. This is most marked at the pyloric end, where the mucosa may be markedly wrinkled, and is associated with polypoid projections. The stomach is usually larger than normal. Sclerotic, atrophic or interstitial gastritis probably is due to the long-continued action of a mild irritant. There is primarily an increase of the connective tissue, which as it contracts causes atrophy of the glands. The mucosa is very much thinner than normal, grayish in color, and in places there are frequently seen large but slight ulcerations; such a stomach is commonly enlarged. From the contraction of the new-formed connective-tissue stenosis of the pylorus sometimes occurs.

Sometimes there may be a great increase of connective tissue with a thickening of the walls and a reduction in size of the organ, cirrhosis ventriculi.

Peptic or round ulcer is a peculiar form of ulceration generally found in the posterior wall in the lesser curvature at the pyloric end of the stomach, and probably due to the action of the gastric juice upon diseased tissue. It is thought to be due to thrombosis of a vessel giving rise to a local area of necrosis, which, being no longer able to resist the action of the gastric juices, undergoes digestion. Infection, embolism, infarction, spasmodic contractions of the blood-vessels, are all thought to have some bearing upon the formation of these ulcers. They are found most frequently in chlorotic girls in whom there is an associated increase in the acidity of the gastric juice. The peptic ulcer is usually single and small, but is sometimes multiple and large. It is generally round or slightly oval, 2 to 4 cm., wider at the top than at the bottom, and is accompanied by very little inflammation. The edges are sometimes thickened and raised by an increase of the connective tissue. The mucous layer alone may be involved, or the destruction may extend to the submucosa, the muscu-laris, or even to the serous covering. In healing there is cicatricial tissue formed which on contracting gives rise to a peculiar white stellate scar. If the ulcer was in the region of the pylorus, stenosis of that outlet may result. From the floor of the healed ulcer carcinoma sometimes develops. The two dangerous results are perforation or hemorrhage. The perforation is usually smooth and round and looks as if it had been punched out. Sometimes there have been adhesions to neighboring organs, so that damage is prevented, but more frequently the gastric contents will escape into the abdominal cavity and give rise to peritonitis. Hemorrhage is the result of ulceration of a large arterial branch. This is more common than perforation. The amount of blood lost may cause death or there may be merely a constant oozing.

Fig. 149. - Chronic Perforating Ulcer of the Stomach (Delafield and Prudden).