What is the recommended evaluation and management for an adult with chronic abdominal pain (>3 months) without red‑flag symptoms?

Evaluation and Management of Chronic Abdominal Pain Without Red Flags

For an adult with chronic abdominal pain (>3 months) without red-flag symptoms, establish a working diagnosis of irritable bowel syndrome (IBS) or functional pain after completing limited baseline investigations, then initiate symptom-directed therapy rather than pursuing extensive diagnostic testing. 1, 2

Define Chronic Abdominal Pain

• Abdominal pain is considered chronic when it persists for 3-6 months beyond acute onset 3
• For IBS diagnosis specifically, symptoms must be present for at least 6 months with diagnostic criteria fulfilled for the past 3 months 3, 1
• Chronic pain becomes independent of peripheral stimuli and involves biological, psychological, and social triggers 3

Initial Screening for Red Flags

Proceed with colonoscopy and extensive workup if ANY of the following are present:

• Age ≥45-50 years at symptom onset 1, 4
• Unintentional weight loss ≥5 kg 1, 4, 5
• Rectal bleeding or positive fecal occult blood test 1, 4, 5
• Iron deficiency anemia 1, 4, 5
• Nocturnal symptoms that awaken the patient 5
• Fever suggesting infection or inflammation 5
• Family history of colorectal cancer or inflammatory bowel disease 1, 4
• Persistent diarrhea >10-14 days 5

Limited Baseline Investigations (When No Red Flags Present)

Complete the following tests to exclude organic disease:

• Complete blood count to detect anemia 1, 5
• C-reactive protein or ESR to assess for inflammation 3, 1, 5
• Celiac serology (anti-tissue transglutaminase IgA with total IgA) 1, 5
• Fecal calprotectin to exclude inflammatory bowel disease 3, 1
• Fecal occult blood test 4, 5

Do NOT proceed with colonoscopy, CT imaging, or extensive testing if these are normal and no red flags exist. 2, 6

Establish Working Diagnosis

If baseline investigations are normal and no red flags present:

• Diagnose IBS based on Rome III criteria: recurrent abdominal pain ≥3 days/month associated with two or more of: improvement with defecation, onset with change in stool frequency, or onset with change in stool form 3, 1
• Recognize that pain may represent functional disorder with central sensitization, allodynia (innocuous stimuli perceived as painful), or hyperalgesia (exaggerated response to noxious stimuli) 3
• Document this as a working diagnosis and avoid premature definitive labeling, as erroneous organic diagnoses complicate management of psychosocial contributors 3

Initial Management Strategy

Initiate symptom-directed therapy without further testing:

• For constipation-predominant symptoms: prescribe 25 g/day dietary fiber 4
• For diarrhea-predominant symptoms: trial low-FODMAP diet 5
• Consider low-dose tricyclic antidepressants for pain modulation 3
• Provide patient education that pain is real, multifactorial, and involves brain-gut interactions 3

Identify Risk Factors for Chronic Pain Persistence

Assess and address these factors early:

• History of prior chronic pain conditions 3
• Early-life adversity, trauma, discrimination, or poverty 3
• Poor coping styles including catastrophizing 3
• Pre-existing anxiety or depression 3
• Opioid use or drugs with anticholinergic effects 3
• Psychosocial problems or abnormal illness behavior 3
• Pain-reinforcing factors (disability claims, worker's compensation, substance misuse history) 3

When to Escalate Care

Refer to multidisciplinary team if:

• Symptoms persist or worsen after 3-6 months of initial management 1, 5
• Malnutrition develops (BMI <18.5 kg/m² or >10% unintentional weight loss in 3 months) 3
• Patient requires cognitive behavioral therapy, hypnotherapy, or psychiatric intervention for pain management 3
• New red-flag symptoms emerge during follow-up 1, 4

Critical Pitfalls to Avoid

• Do not repeat testing once functional diagnosis is established – this reinforces illness behavior and increases healthcare costs without improving outcomes 2, 6
• Do not delay addressing psychosocial factors – waiting for "recovery time" before intervening for disproportionate pain allows acute pain to convert to chronic pain 3
• Do not dismiss patient concerns – explain that central pain mechanisms are real neurobiological processes, not psychological weakness 3
• Do not prescribe opioids – these worsen dysmotility and contribute to chronic pain maintenance 3