Appendicitis : Epidemiology and diagnosis

Sammanfattning: The study concerns appendicitis, its epidemiology and diagnosis, and the outcome of appendectomy. A population based cohort of 9,274 patients undergoing appendectomy in 1969 to 1990 in Jönköping County was retrospectively studied, and 502 patients admitted for suspected appendicitis to the hospitals in Jönköping and Eksjö between October 1992 and December 1993 were prospectively studied.Appendicitis was found to occur in outbreaks and space-time clusters, indicating an infectious etiology. The incidence of non-perforating appendicitis was strongly age-dependent, with a peak in adolescence, whereas the incidence of perforating appendicitis was stable at all ages. This suggests that perforating and non-perforating appendicitis are separate entities.There was a high rate of negative appendectomies, but during the study period an increasing diagnostic accuracy and decreasing incidence of negative appendectomies was observed, indicating a trend towards a more restrictive attitude to exploration in patients with suspected appendicitis. This was accompanied by a decreasing incidence of non-perforating appendicitis, whereas the incidence of perforating appendicitis was stable. An analysis of population based studies showed a strong relation between surgeons' attitude to exploration and the incidence of non-perforating ap9endicitis, whereas the incidence of perforating appendicitis was unrelated. This is consistent with a high proportion of potentially resolving appendicitis.A conservative management decreases the munber of negative explorations and saves a number of patients with resolving appendicitis from an unnecessary operation. This leads to a high proportion of perforations among the operated patients but the number of perforations is not increased. The perforation rate, therefore, should not be used as a quality measure of the management of patients with suspected appendicitis.The rate of negative explorations is higher in women. This gender difference is found at all ages and is not due to gynecological diseases alone. The explanation is the larger number of women attending for nonsurgical abdominal pain, whereas the rate of diagnostic errors among these patients is similar in men and women.Patients with a negative appendectomy are characterized by high intensity of pain and tenderness without signs of a systemic inflammatory response. Surgeons pay too much attention to pain and tenderness in their decision to operate, and underestimate the importance of temperature, laboratory variables and duration of symptoms.No single clinical or laboratory variable has sufficiently high discriminating power to be used as a true diagnostic test. The inflammatory variables are as important predictors as the clinical findings, and they are especially important in advanced appendicitis. Their diagnostic value is higher at a repeat examination after a few hours of observation.The study show for a need of an improved management of patients with suspected appendicitis, and the potential for improved clinical diagnosis. Inflammatory variables should be given more attention, and pain and tenderness should be interpreted more cautiously. An expectant management, with repeated clinical and laboratory examinations, is advisable once advanced appendicitis has been ruled out.