Intraperitoneal Localized Abscess: Roentgenologic Aid in Diagnosis

Abstract

Localized intraperitoneal abscess is a clinical diagnosis which is usually established without difficulty. The history, the localized tenderness, and the high white count are all factors which assist in making the diagnosis. Occasionally, however, cases arise in which the usual methods are not adequate or do not serve to locate the suspected collection of pus. Especially is this true following operations, when three or four surgical possibilities demand consideration and elimination, and we have no clues to the presence or location of an abscess. The most frequent sites for such collections are the retroperitoneal space and the subphrenic space. We shall consider here the less frequent intra-abdominal abscess and suggest some aids in x-ray diagnosis. Any help we can give the surgeon in localizing an intra-abdominal abscess is of utmost importance, not only from the standpoint of diagnosis but more especially as making possible a direct approach to the diseased area without subjecting the patient to an exploratory laparotomy. We have been fortunate in having been able to furnish such aid in some obscure cases by means of a simple x-ray examination. The x-ray findings in these cases depend on localized ileus; absence of the properitoneal fat line is also of significance. Alvarez and Hosoi (1) showed by experimental work that irritation of the peritoneum will produce an inhibitory impulse acting on the digestive tract and causing a paralysis of the intestine. An abscess probably acts as such an irritation to the peritoneum and produces an inhibitory impulse affecting the neighboring loops of intestine. In the absence of peristalsis the gas which is normally present in small amounts and which is carried in solution is no longer propelled forward. Stasis occurs, causing the gas and fluid to increase and become visible on the x-ray film (2, 3). We have not under these conditions a true paralytic ileus but the activity of the bowel is inhibited or restrained by an over-active sympathetic influence. The abscess may cause secondarily an edema of the properitoneal fat, or it may infiltrate this layer of fat. The properitoneal fat is the layer next to the endothelial lining of the peritoneal cavity. On properly exposed films it is seen as a dark stripe. When it is infiltrated with fluid, as may occur in the presence of an abscess adjoining the peritoneal lining, the contrasting dark stripe is lost (4). These two findings, localized ileus plus obliteration of the properitoneal fat line in the neighborhood, will definitely establish a diagnosis of an intraperitoneal abscess. It may be necessary to take repeated films to be certain that the localized ileus is constant. Indeed, if the diagnosis is obscure and the only positive findings are those demonstrated roentgenologically, it is most important that the examination be repeated, as the consequences of an erroneous diagnosis may be grave, whereas a correct diagnosis may lead to life-saving therapy.