Context

Abdominal symptoms and pain are encountered in 5–10% of primary healthcare visits both in children and adults. The most common diagnoses in the emergency wards are non-specific abdominal pain (NSAP) and acute appendicitis accounting for 34–50% and 20–30% of all cases, respectively.1–3 NSAP implies short-lived, self-limited, acute abdominal pain for which no serious or definite organic cause is ever established. NSAP is common exclusion diagnosis for abdominal discomfort in childhood.

Findings

Only a relatively small number (5.8%) of patients with previous NSAP were later diagnosed in hospital with underlying bowel pathology. Clinically relevant age-stratified risks of specific organic diseases following a diagnosis of NSAP were significantly elevated. There was a 4.84 (95% CI 4.45 to 5.27) times greater risk of Crohn's disease and a 4.23 times (4.13 to 4.33) greater risk of acute appendicitis compared to controls. The risk of IBS was 7.22 (6.65 to 7.85) times greater compared to controls. An increased rate of bowel pathology among patients with previous NSAP was observed even beyond 10 years after first hospital admission with abdominal pain.

Commentary

The present study indicates that although the majority of children with NSAP (ie, 90%) were later free of abdominal symptoms, their relative risk was increased for later abdominal disorders, compared to children without NSAP, even at 10 years. Similar results have been reported in adult patients suffering from NSAP.2 Over 70% of patients were free of symptoms after 20 years of follow-up, but their mortality was higher and various alimentary track diseases were more frequently observed than in controls.

The incidence of both NSAP and acute appendicitis is declining in many countries.4 About 40–50% of adults abdominal pain is thought to be of functional origin, and in children this increases to 80–90%.2 ,5 Only 1.6% of children with a diagnosis of NSAP were later found to have an identifiable organic cause.⁶  It was somewhat surprising that the rate of subsequent acute appendicitis or coeliac disease was elevated in children who had suffered from NSAP. This relationship may have no causal link, it may imply a delay in diagnosis or potentially a more chronic nature of acute appendicitis than we appreciate. One limitation of the study was the usage of discharge diagnoses for data collection. The discharge diagnosis of NSAP is an exclusion diagnosis, which can be an estimate and may include misclassification errors or inaccuracies.

Implications for practice

This study indicates that a small number of patients with abdominal pain syndrome are prone to having continuing symptoms throughout their life. We need to re-assess diagnostic strategies in primary and secondary care to minimise unnecessary use of expensive investigations, as >90% of patients with NSAP were symptom free at follow-up. Psychological factors and functional disorders are very common among these patients. Real cost savings could be achieved if more diagnostic tests (ie, Helicobacter pylori, lactose intolerance, coeliac disease, calprotectin) were conducted in primary healthcare centres for these patients.