Pneumatosis Cystoides Intestini

PNEUMATOSIS CYSTOIDES INTESTINI (syn. emphysema intestinalis), air cysts of the intestine, a rare disease consisting in the formation on a limited segment of the intestinal wall of a group of cysts filled with gas. P. c. i. was first described in 1825 by Meyer in pigs, in which this disease occurs frequently; in man, in which it was first observed in 1876 by Bang, it is a very great rarity (up to the present time not more than 80 cases have been described). The lesion usually involves the small intestine over a length of 8-12 cm; less often it extends to more significant parts of the intestine; in isolated cases there was also a lesion of the large intestines, and in one case (Plenge) the change involved the wall of the stomach. Gas bubbles are arranged in the form of a tight group and bulge under the serous covering of the part of the intestinal tube opposite the place of attachment of the mesentery; some of the cysts sometimes hang outside the intestine on a thin stalk. The sizes of the cysts are usually different: from a millet grain to a walnut; less often the formation of a mass of small cysts was observed, and in such cases the change resembled alveolar echinococcus; the formation of cysts of the size of a pea and larger has also been described. Data on the composition of the gas contained in the cysts are very inaccurate; usually it is stated that the contents of the cysts resemble atmospheric air (10-20% oxygen and 80-90% nitrogen), however this causes quite well-founded doubt among many researchers (Siegmund and others); some found carbon dioxide and hydrogen in the cysts. Microscopic examination reveals that, for the most part, the cysts are located outside the muscular layer of the intestine in the subserous connective tissue, which in this case undergoes significant proliferation. Less often cysts are found among the muscular layer and in the submucous connective tissue. The cysts have no separate wall; their inner surface usually does not show a cellular lining, sometimes however flat endothelial cells are found on it. Inflammatory infiltrates are often found in the connective tissue between the gas cysts; giant cells of the type of foreign body giant cells are often located right next to the cysts. A frequent finding in P. c. i. is a change in the lymphatic vessels of the intestinal wall, consisting in the proliferation of their endothelium (endolymphangiitis proliferans; Demmer). Some found proliferation of granulation tissue in the walls of the cysts and pictures as if of their healing. The aforementioned changes of the intestinal wall can give rise to narrowing of its lumen; on the other hand, the accompanying development of cysts, proliferation of connective tissue leads to local fibroblastic peritonitis with the formation of adhesions and synechiae. Clinically, P. c. i. either gives a picture of a tumor with signs of intestinal stenosis or reveals itself as a picture of acute obstruction as a result of strangulation incarceration; in the greater part of the described cases of human P. c. i. the suffering was established at laparotomy undertaken for one of the aforementioned clinical pictures; less often it was encountered only at autopsy. Regarding the pathogenesis of P. c. i., all researchers agree that the gas appears in the lymphatic pathways of the intestinal wall from the side of the mucous membrane and subsequently penetrates into the subserous connective tissue, being partly in the lymphatic vessels, partly freely in the connective tissue. As for where this gas comes from, the solution of this question is strongly complicated by the absence of exact data on the chemical composition of the gas; in general there are two theories on this matter. 1) The mechanical theory assumes the possibility of purely mechanical penetration of gases from the lumen of the intestine into the lymphatic pathways of its wall (analogy with traumatic cutaneous emphysema). This theory is supported by the fact that P. c. i. is often (in 70% of cases) combined with other changes of the intestines accompanied by damage to the mucous membrane, meteorism, etc., such as gastric and duodenal ulcer, gastric cancer, intestinal tuberculosis, appendicitis, stagnant catarrh of the stomach and intestines. 2) The bacterial theory is connected with the assumption of the introduction of gas-forming bacteria into the lymphatic pathways of the intestine (analogy with cystitis emphysematosa). Findings in the walls of cysts of Gram-positive rods or bacteria of the Bact. coli com. type speak in favor of this theory, especially the isolation of pure cultures of gas-forming microorganisms from the gas cysts (Abrikosov). For P. c. i. of pigs, Joest considers the bacterial origin of the disease to be proven.

A. Abrikosov,