Peritonitis

PERITONITIS, inflammation of the peritoneum. (See COELOM AND SEROUS MEMBRANES.) It may be acute or chronic, and either localized or diffused.

Acute peritonitis

commonly follows such conditions as hernia and obstruction of the bowels, wounds penetrating the abdomen, perforation of viscera, as in ulcer of the stomach, and of the in testine in typhoid fever, bursting of abscesses or cysts into the ab dominal cavity, and extension of inflammation from some abdom inal or pelvic organ, such as the appendix, the uterus or bladder. At first localized, it may afterwards become general. The changes in the peritoneum are congestion ; exudation of lymph in greater or less abundance, at first greyish and soft, thereafter yellow, be coming tough and causing the folds of the intestine to adhere to gether; effusion of fluid, either clear, turbid, bloody or purulent.

Acute peritonitis usually begins with a shivering fit, vomiting and pain in the abdomen with extreme tenderness, so that pressure, even of the bed-clothes, cannot be borne. The patient lies on the back with the knees drawn up to relax the abdominal muscles ; the breathing becomes rapid and shallow, and is performed by move ments of the chest only, the abdominal muscles remaining quiescent—which is not the case in healthy respiration. The ab domen becomes swollen by flatulent distension of the intestines, which increases the distress. There is usually constipation. The skin is hot ; the pulse is small, hard and wiry ; the face is pinched and anxious. When the peritonitis is due to perforation—as may happen in the case of gastric ulcer or of ulcers of typhoid fever, or in the giving way of a loop of strangulated bowel—the above mentioned symptoms and fatal collapse may all take place in from twelve to twenty-four hours. The puerperal form of this disease, which comes on within a day or two after childbirth, is often rapidly fatal. The actual cause of death is the absorption of the poisonous bacterial products formed in the peritoneal cavity. Chronic peritonitis may follow a localised acute attack, or may be tuberculous. In the former case, the gravest symptoms having subsided, some abdominal pain continues, and there is swelling of the abdomen, due to thickening of the peritoneum, and the presence of fluid. This kind of peritonitis may also develop slowly without any preceding acute attack.

Tuberculous peritonitis

occurs either alone or in association with tuberculous disease of a joint or of the lungs. Often it is associated with tuberculous mesenteric glands, particularly in children. The chief symptoms are abdominal discomfort, or pain, and distension of the bowels. The patient may suffer from either constipation or diarrhoea, or each alternately. Along with these local manifestations there may exist high fever, rapid emaciation and loss of strength. But some cases of tuberculous peritonitis

present few symptoms of any kind. In some cases, the neighbour ing coils of intestine having been glued together, a collection of serous fluid takes its place in the midst of the mass, and, being walled in by the adhesions, forms a rounded tumour, dull on per cussion, but not tender or painful. Such cases, when occurring in women, are apt to be mistaken for cystic disease of the ovary.

The sole treatment of acute peritonitis is surgical. PERIWINKLE, the popular name of a genus of Gastropod molluscs (Littorina) of wide distribution in temperate and cold seas. They are all of small size and have spiral, roughly globular shells, which in some species are smooth, in others ornamented with low spiral ribs. Some 8o living species of Littorina have been described and there are many fossil forms. The common British Littorina littorea, about an inch long, has a wide range of colour variation. This species appeared on the shores of New Brunswick and Nova Scotia between 185o and 186o and was found on the coast of Maine in 1868. It has since spread rapidly along the American coast, and is now common as far south as Delaware Bay. Among species native to North American shores are L. rudis, very abundant from New Jersey to the Arctic ocean and found also on the Pacific coast, and L. palliata, common from New Jersey to far northern shores. Both the last-named species are smaller than L. littorea. L. irrorata, about equal in size to L. littorea, is frequent from Vineyard sound to Florida.

Systematically the periwinkles are placed among the Taenio glossate Pectinibranchs and are allied to the river snails (Vivip arc) and the cowries (Cypraea). The anatomy of certain species has been studied and has been found to exhibit a peculiar modifi cation of the gills, the filaments of which are prolonged across the surface of the mantle-cavity (see MOLLUSCA) and are broken up into vascular branches, so as to transform the mantle-cavity into an organ of aerial respiration. Littorina littorea is sometimes found beyond high-water mark and has been found half a mile from the sea.

According to Blegvad Littorina littorea is both herbivorous and carnivorous, feeding on algae, seaweeds and small molluscs and crustacea (Ostracods). The majority of the species seem to be found in the Laminaria and Fucus zones of the sea shore. The eggs of these molluscs are deposited either singly or in masses. Some species (e.g., L. rudis and neritoides) are viviparous and the free-swimming larval stages are suppressed.

Periwinkles are to be reckoned among the most common edible molluscs. In 1922, 3,245 tons were delivered in Billingsgate fish market.

See M. Caullery and P. Pelseneer, Bull. Sci. France et Belgique 0910 ; W. M. Tattersall, "Fisheries, Ireland," Sci. Invest. (1920).

(G. C. R.)