Perforating appendicitis: is it a separate disease?

Objective: To find out whether perforated and unperforated appendicitis are separate diseases and can be distinguished clinically. Design: Prospective multicentre study. Setting: 11 departments of surgery in Germany and Austria. Subjects: 519 patients over 6 years old who had histologically confirmed ac ute appendicitis between October 1994 and March 1996. Main outcome measures: Differences in history, clinical findings, lab resul ts, clinical course and outcome. Results: 92 of the 519 patients (18%) had perforated appendicitis. The foll owing variables were shown by univariate analysis to be significantly more common in the group with perforated appendicitis: rigiditiy, reduced abdomi nal wall movement, abdominal distension, reduced bowel sounds tall p < 0.00 1), pale skin (p < 0.005), generalised abdominal tenderness, severe abdomin al tenderness (both p < 0.01), WCC greater than or equal to 10(9)/L (p < 0. 05). By multivariate analysis the following variables were significantly mo re common in the group with perforated appendicitis: age over 50 years (p < 0.0001); change in bowel habit and rigidity of the abdominal wall (both p = 0.001); generalised tenderness (p < 0.01); male sex (p < 0.01); and diste nded abdomen (p < 0.05). Rectal examination failed to make the distinction. Conclusions: Perforated and unperforated appendicitis behave clinically lik e two different diseases. They can in most cases reliably be distinguished using clinical criteria alone. Although greater diagnostic accuracy may res ult in a higher rate of perforation, close observation and timely intervent ion will only marginally affect the outcome.