[Chronic appendicitis as an independent clinical entity].

INTRODUCTION: Chronic appendicitis is not generally accepted as an independent clinical entity. The diagnosis is often made only after histological analysis when the patient has undergone appendectomy in a case of persistent or recurrent pain. The objectives of this prospective study were to analyse the incidence of chronic appendicitis among our patients, to compare demographic and clinical data with histological results and to evaluate long-term follow-up after appendectomy.
METHODS: Between November 1995 and February 1998, 322 patients underwent appendectomy due to typical symptoms of appendicitis. All appendices were analysed macroscopically by the surgeon and histologically by two independent pathologists. Furthermore, demographic data, standard blood results, Alvarado score, body mass index, operation time, complications, and length of hospital stay were evaluated. In April 2001, a long-term follow-up survey evaluated the present complaints of all operated patients.
RESULTS: A total of 112 patients showed clinical signs of non-acute appendicitis. However, 26.8% of these appendices histologically revealed an acute inflammation. In the subgroup of histologically non-acute appendicitis, 4.9% of the appendices were inconspicuous, 42.0% chronically inflamed and 50.6% fibrotic. Compared to that, the macroscopic examination by the surgeon resulted in a 93.5% specificity and a 77.8% sensitivity. The preoperative period of pain was significantly longer (7 days) compared to patients with acute appendicitis (0.5 days). White blood count (8.700 versus 13.400) and preoperative Alvarado score (4 versus 7 points) were significantly lower, the hospital stay significantly shorter (3 versus 4 days). A specificity of 89.9% and a positive likelihood ratio of 4.64 were calculated for an optimal cut-off value of 7 days for preoperative pain. At a median of 50.2 months after the operation, 93.1% of the patients were asymptomatic, and five patients reported persistent pain in the right lower quadrant.
CONCLUSIONS: Three quarter of all patients with pain in the right lower quadrant but no significant signs of inflammation showed the histological criteria for chronic appendicitis. However, histology revealed signs of an acute inflammation in 25% of patients. An optimal cut-off value of 7 days preoperative period of pain was able to suggest a histologically non-acute appendicitis with a high specificity and a high positive predictive value. More than 93% of these patients were asymptomatic in their long-term follow-up. Chronic appendicitis must be assumed in cases of recurrent or persistent pain longer than 7 days and an elective appendectomy has to be recommended.