Objective-To clarify poorly understood epidemiological features ofappendicitis.Design-Retrospective study of consecutive cases from a defined population and analysis of data from published studies.Setting-County of Jonk6ping, Sweden. 3029 patients who underwent operation in and 4717 patients from the county town who underwent operation in 1970-89, all for suspected appendicitis, plus 48 426 cases from six reported studies.Main outcome measures-Incidences specific for age and sex and temporal trends of perforating and non-perforating appendicitis and removal of a normal appendix. Associations between diagnostic accuracy, rate of perforation, and incidences of removal ofa normal appendix and ofperforating and non-perforating appendicitis.Results-The incidence of appendicitis was 116/100000 inhabitants. Appendicitis was more common in male patients. The incidence ofperforating appendicitis was independent of age, stable over time, and uninfluenced by the rate of laparotomy, whereas the incidence of non-perforating appendicitis was age dependent, decreasing over time, and related to the diagnostic accuracy and rate of removal ofa normal appendix. Conclusions-Perforating and non-perforating appendicitis seem to be separate entities, and appendicitis that resolves spontaneously is common.

The clinical diagnosis of appendicitis needs to be improved, as up to 40% of explorations for suspected appendicitis are unnecessary. The use of body temperature and laboratory examinations as diagnostic aids in the management of these patients is controversial. The diagnostic power of these variables compared to that of the disease history and clinical findings is not well studied. In this study we prospectively assessed and compared the diagnostic value of 21 elements of the history, clinical findings, body temperature, and laboratory examinations in 496 patients with suspected appendicitis. The diagnostic value of each variable was compared from the area under the receiver operating characteristic (ROC) curve and the likelihood ratios (LR). Logistic regression was used to analyze the diagnostic value of a combination of variables and to analyze independent relations. No single variable had sufficiently high discriminating or predicting power to be used as a true diagnostic test. The inflammatory variables (temperature, leukocyte and differential white blood cell (WBC) counts, C-reactive protein) had discriminating and predicting powers similar to those of the clinical findings (direct and rebound abdominal tenderness and guarding). Anorexia, nausea, and right-sided rectal tenderness had no diagnostic value. The leukocyte and differential WBC counts, C-reactive protein, rebound tenderness, guarding, and gender were independent predictors of appendicitis with a combined ROC area of 0. 93 for appendicitis. This showed that inflammatory variables contain important diagnostic information, especially with advanced appendicitis. They should therefore always be included in the diagnostic workup in patients with suspected appendicitis.

In-hospital observation with repeated clinical examinations is commonly used in patients with an equivocal diagnosis of appendicitis. It is not known if repeated measurements of temperature and laboratory examinations have any diagnostic importance in this situation. The importance of repeated measurements of the body temperature, white blood cell (WBC) and differential cell counts, C-reactive protein concentration (CRP) and of the surgeon's repeated assessments was prospectively analyzed in 420 patients with an equivocal diagnosis of appendicitis at admission who were reexamined after a median of 6 hours of observation. The final diagnosis was appendicitis in 137 patients. After observation the inflammatory response was increasing among patients with appendicitis and decreasing among patients without appendicitis. The variables discriminating power for appendicitis consequently increased, from an area under the receiver operating characteristic (ROC) curve of 0.56 to 0.77 at admission, to 0.75 to 0.85 after observation. The ROC area of the surgeons' clinical assessment increased from 0.69 to 0.89. The WBC and differential cell counts were the best discriminators at the repeat examination. The change in the variables between the observations had weak discriminating power and had no additional importance in addition to the actual level at the repeat examination. To conclude, the diagnostic information of the temperature and laboratory examinations increased after observation. Repeated controls of the body temperature and laboratory examinations are therefore useful in the management of patients with equivocal signs of appendicitis, but the result of the examinations must be integrated with the clinical assessment.

Background-Experimental, clinical, and epidemiological studies have implicated mitogenic metabolites of arachidonic acid such as prostaglandin E 2 (PGE 2 ) in colorectal carcinogenesis. Recently, cyclooxygenase 2 (COX-2) which catalyses the conversion of arachidonic acid to PGE 2 , has displayed increased levels in human colorectal cancer. Aims-To evaluate whether there is diVerential COX-2 expression from diVerent locations (caecum, ascending, transverse, descending, or sigmoid colon, and rectum) in human colorectal cancer. Methods-Protein levels of COX-2 were determined by western blot analysis in tumours and adjacent normal mucosa of 39 patients with colorectal cancer. (Gut 1999;45:730-732) Results-There was a notable overexpression of COX-2 protein in tumours located