RAP is very commonly observed in the pediatric population affecting around 10%–20% of school-going children. The term “recurrent abdominal pain” should not be used as a diagnosis; it is encompassed in the term “chronic abdominal pain” and is a heterogeneous disorder. Recurrent abdominal pain was defined by four criteria:
- ≥3 episodes of abdominal pain
- Pain sufficiently severe to affect activities
- Episodes occur for ≥3 months
- No known organic cause
Recurrent abdominal pain of childhood encompasses both organic and functional etiologies though functional causes are common; organic causes need to be excluded.
Functional disorders are conditions in which the patient has variable combinations of symptoms without any readily identifiable or strong suspicion of a distinctly organic condition. Functional disorders are now referred to as “disorders of gut-brain interaction” to emphasize the interplay between the enteric & central nervous systems and gastrointestinal and psychosocial factors contribute to symptoms. These disorders may be associated with visceral hyperalgesia (reduced threshold for pain), abnormal pain referral after rectal distension, or impaired gastric relaxation response to meals.
These disorders are categorized into four subtypes:
- Functional dyspepsia
- Irritable bowel syndrome (IBS)
- Abdominal migraine
- Functional abdominal pain not otherwise specified. Functional constipation is grouped separately as a functional defecation disorder but is a consideration when evaluating symptoms of chronic abdominal pain.