Diagnostic Criteria for Pediatric Functional Abdominal Pain Disorders
The Rome IV criteria provide the definitive diagnostic framework for pediatric functional abdominal pain disorders, requiring symptoms to be present for at least 2 months (not 3 months as in adults) with symptom onset at least 6 months before diagnosis, and no evidence of organic disease that explains the symptoms. 1
Core Diagnostic Requirements Across All Pediatric FAPDs
- Symptom duration: Symptoms must occur at least once per week for a minimum of 2 months, with onset at least 6 months prior to diagnosis 1
- Absence of organic disease: No structural, infectious, inflammatory, or metabolic abnormalities that explain symptoms after appropriate evaluation 2, 1
- Functional impairment: Symptoms must be severe enough to interfere with daily activities 2
1. Irritable Bowel Syndrome (IBS)
Diagnostic Criteria
- Abdominal pain occurring at least 4 days per month, associated with one or more of the following 1:
- Pain related to defecation (may increase or decrease with bowel movements)
- Change in stool frequency
- Change in stool form or appearance 1
Subtypes Based on Stool Pattern
- IBS with constipation (IBS-C): Hard or lumpy stools ≥25% of the time, loose or watery stools <25% of the time 3
- IBS with diarrhea (IBS-D): Loose or watery stools ≥25% of the time, hard or lumpy stools <25% of the time 3
- IBS mixed type (IBS-M): Both hard/lumpy stools and loose/watery stools ≥25% of the time 3
Key Clinical Features
- Passage of mucus with stool is supportive but not required for diagnosis 4, 5
- Pain may be relieved by defecation in only 10% of cases, contrary to common belief 3
- Symptoms often worsen with stress, large meals, and inadequate sleep 3
2. Functional Dyspepsia (FD)
Diagnostic Criteria
- One or more of the following symptoms occurring at least 4 days per month 6, 1:
- Postprandial fullness (severe enough to impact usual activities)
- Early satiation (severe enough to prevent finishing a regular-sized meal)
- Epigastric pain (not related to defecation)
- Epigastric burning 6
Subtypes
- Postprandial Distress Syndrome (PDS): Predominant symptoms are bothersome postprandial fullness and/or early satiation occurring at least 3 days per week 6
- Epigastric Pain Syndrome (EPS): Predominant symptoms are bothersome epigastric pain and/or burning occurring at least 1 day per week 6
Distinguishing Features
- Symptoms localized primarily to the epigastric region, not lower abdomen 3
- Pain may be induced or relieved by meals, or occur while fasting 6
- Heartburn is not a dyspeptic symptom but may coexist 6
- Symptoms relieved by defecation or passage of gas should not be considered dyspepsia 6
3. Functional Abdominal Pain - Not Otherwise Specified (FAP-NOS)
Diagnostic Criteria
- Episodic or continuous abdominal pain occurring at least 4 days per month 1, 7
- Pain does not meet criteria for IBS, functional dyspepsia, or abdominal migraine 2, 1
- Pain is not exclusively related to bowel movements, meals, or menses 1
Clinical Characteristics
- Pain location may be periumbilical or diffuse, not necessarily epigastric 1
- No consistent relationship between pain and physiological events (eating, defecation) 2
- Often associated with psychological comorbidities including anxiety and depression 1
4. Abdominal Migraine
Diagnostic Criteria
- Paroxysmal episodes of intense, acute periumbilical, midline, or diffuse abdominal pain lasting ≥1 hour 2, 1
- Episodes occur at least twice over a period of time 1
- Pain is incapacitating and interferes with normal activities 1
Associated Features (Must Have Two or More)
Distinguishing Characteristics
- Complete resolution of symptoms between episodes (pain-free intervals) 1
- Episodes are stereotypical in the same patient 1
- Family history of migraine headaches is common 2
Critical Red Flags Requiring Investigation
The following alarm features mandate exclusion of organic disease before diagnosing any FAPD 5, 8:
- Age of onset <5 years or presentation after puberty
- Involuntary weight loss or growth deceleration
- Gastrointestinal bleeding (hematemesis, melena, hematochezia)
- Persistent vomiting, especially bilious or nocturnal
- Chronic severe diarrhea
- Persistent fever
- Nocturnal symptoms that awaken the child from sleep
- Perianal disease (fissures, fistulas, skin tags)
- Family history of inflammatory bowel disease, celiac disease, or peptic ulcer disease
- Arthritis or unexplained rash 8, 1
Diagnostic Approach
Initial Evaluation
- Complete blood count to exclude anemia 5, 8
- Inflammatory markers (ESR or CRP) to screen for inflammatory bowel disease 5
- Celiac serology (tissue transglutaminase IgA with total IgA) 5
- Stool studies: Fecal calprotectin if diarrhea predominant; ova and parasites if travel history 5
When Additional Testing Is NOT Indicated
- In the absence of red flags, extensive diagnostic testing is not recommended and increases healthcare costs without improving outcomes 8, 9
- Studies show that 89.2% of children presenting with abdominal pain have functional causes, and only 26.8% require any diagnostic testing 9
- Routine endoscopy, imaging, and laboratory panels in children meeting Rome IV criteria without alarm features have extremely low diagnostic yield 8