Peritoneal aspiration cytology as a diagnostic aid in acute appendicitis

The pathology of acute appendicitis

Although acute appendicitis is frequent, it is subject to common misconceptions. Furthermore, there is little good evidence to support some of our beliefs. This report reviews the role of the anatomic pathologist in diagnosis when acute appendicitis is suspected clinically and discusses what is known of its pathology. The conclusions that can be legitimately drawn from the literature are emphasized. A classification is proposed that incorporates intraluminal inflammation, acute mucosal inflammation, acute mucosal and submucosal inflammation, suppurative (phlegmonous) appendicitis, gangrenous appendicitis, and periappendicitis, and the significance of each of these diagnoses is discussed. The etiology and pathogenesis of acute appendicitis is reviewed. Contrary to popular belief, the best evidence indicates that obstruction is unlikely to be the primary cause, at least in the majority of cases. Ancillary techniques in the diagnosis of appendicitis, including laparoscopy and peritoneal aspiration cytology, are discussed.

The pathobiology of peritonitis

The peritoneum is more than a mechanical covering that allows for the easy gliding of opposed peritoneal surfaces. The peritoneal mesothelial cells facilitate the action of powerful innate immune mechanisms. In addition, the peritoneal-associated lymphoid tissues contain unique cells that may play a crucial role in the localization of intraperitoneal infection. A clearer understanding of the molecular and cellular events underlying peritoneal functions in both the unstimulated and stimulated state will aid future treatment of peritonitis.

Have the evaluation and treatment of acute appendicitis changed with new technology?

The evaluation and treatment of acute appendicitis remain essentially unchanged for the majority of individuals who present with this disease. Although advancements have been made in laboratory analysis as well as imaging via ultrasonography and CT, nothing can replace careful evaluation by an experienced surgeon. Appendicitis remains a diagnosis based primarily on history and physical examination, with further studies being useful adjuncts in atypical cases--more likely to occur in the very young or very old and most cost effective when ordered by the surgical consultant. Improvement in outcomes has not been demonstrated with routine use of "new technology." The treatment of acute appendicitis continues to be early surgical intervention. Although laparoscopic appendectomy may offer advantages in women of childbearing age and in obese individuals, its routine use is not indicated based upon current reports in the literature. Debate continues regarding the optimal treatment of the periappendiceal mass. Further clinical research regarding early operation compared with intravenous antibiotics with or without drainage, as well as comparison of outcomes with or without interval appendectomy, needs to be performed. With continued research and definition of populations likely to benefit from advances in technology, a more focused application will be possible. This will lead to improved outcomes and decreased overall cost. The issue of delay in treatment, a major determinant of morbidity associated with appendicitis, warrants further evaluation and should be addressed on a population-specific basis. Emphasis should remain on the early clinical diagnosis of acute appendicitis with its associated low morbidity and mortality.

Ultrasonography as an adjunct in the diagnosis of acute appendicitis: a 4-year experience

This study was designed to evaluate the sensitivity and specificity of abdominal ultrasonography as a diagnostic modality in a large series of children who presented with possible appendicitis. From August 1990 to July 1994, 452 children (203 boys, 249 girls) with an average age of 11 years (range, 1 to 20 years) underwent graded compression ultrasonography of the right lower quadrant of the abdomen for the evaluation of possible appendicitis. In the first 18 months of the study all patients with the possible diagnosis of appendicitis (group I; 180 patients) had abdominal ultrasonography after members of the surgical team evaluated and documented their findings in the medical record. In the second study period (30 months), abdominal ultrasonography was recommended only when the clinical diagnosis of acute appendicitis was equivocal (group II; 272 patients). Abdominal ultrasonography was performed using the graded compression technique with a 5.0-MHz linear array transducer. A positive ultrasound study for appendicitis was defined as the presence of an enlarged noncompressible appendix with an outer wall to outer wall diameter of greater than 6 mm, the presence of a complex mass, or the presence of an appendicolith. The sonographic data were correlated with surgical and pathological findings. Appendicitis was confirmed in 112 of the 452 cases. In 17 of these, the appendix was perforated. In the overall group of 452 children, abdominal ultrasonography had a sensitivity of 90%, specificity of 96%, and accuracy of 95%. There was no significant morbidity in the 11 patients with a false-negative study result. All 11 patients had an uncomplicated appendectomy. There were 11 false-positive results; 10 of these patients had a negative laparotomy result (negative laparatomy rate, 8.9%). For the two groups, the sensitivity and specificity of ultrasonography in the diagnosis of appendicitis were equivalent (group 1: 88% sensitivity, 96% specificity; group 2: 92% sensitivity, 97% specificity). On the basis of the high sensitivity and specificity rates, ultrasonography of the appendix can be a useful adjunct to standard examination in the diagnosis of acute appendicitis.