[What are abdominal painful syndromes of unexplained origin? Prospective study: 99 patients followed for three years]

99 patients, 67 of whom were female, with a mean age of 25.5 years, were admitted as emergencies between 1991 and 1992 for acute abdominal pain of unknown aetiology. The follow-up, carried out prospectively, was 100% at 1 month, 98% at 6 months, 95% at 1 year, 84% at 2 years. The patients were divided into 3 groups: group I: 42 patients only underwent investigations; group II: 31 underwent laparoscopy, and the appendix was left in place after being considered to be normal by the surgeon; group III: 26 underwent laparoscopic appendicectomy for a histologically normal appendix. For 90% of patients, the painful episode never returned. In the other cases the pain returned within one year, but there was no difference between the three groups (11.2%, 9.6%, 11.5%) (ns). The causes found at the second admission were largely genital, or rare diseases (Crohn, Spiegel hernia). 2 patients were operated for acute appendicitis, not recognized in Group I. In those who had a laparoscopy (Group II and III), the incidence of persistent pain was identical whether the appendix was considered to be normal by the operating surgeon or found to be normal histopathologically. This study suggests that: after admission for acute abdominal pain of unknown cause, the incidence of recurrence of pains is of the order of 10% within one year; the investigations carried out during the patient's admission, allowed the exclusion of serious diseases for three years; the risk of missing a true appendicitis is small (2.5%) and has no prognostic significance; the finding of a normal appendix during laparoscopy should not necessarily lead to its removal; one year follow-up is sufficient to assess the outcome of abdominal pain of unknown cause.