What is the appropriate treatment for abdominal pain?

Treatment of Abdominal Pain

The treatment of abdominal pain must be guided by first identifying whether the underlying cause requires urgent surgical intervention versus medical management, with imaging (CT abdomen/pelvis) playing an essential role in acute presentations to establish the diagnosis and direct appropriate therapy. 1

Initial Assessment and Diagnostic Approach

The primary goal when evaluating abdominal pain is to rapidly determine if the patient requires emergency surgery versus conservative management. 1, 2

Key diagnostic steps:

• Imaging is critical for acute nonlocalized abdominal pain - CT abdomen/pelvis is the most appropriate initial imaging modality, as it identifies pathology across multiple organ systems and changes management in 51% of cases and admission decisions in 25% of patients. 1

• Common surgical causes requiring immediate identification include: appendicitis (one-third of ED presentations), acute cholecystitis, small bowel obstruction, perforated peptic ulcer, bowel infarction, and intra-abdominal abscesses. 1

• Plain abdominal radiography should be obtained during acute episodes when obstruction is suspected, followed by therapeutic trials if negative. 1

Treatment Based on Underlying Diagnosis

For Irritable Bowel Syndrome (IBS) - Functional Abdominal Pain

First-line treatments:

• Lifestyle modifications: Regular exercise should be advised for all IBS patients. 1

• Dietary interventions:

  • Soluble fiber (ispaghula) 3-4 g/day, gradually increased, is effective for abdominal pain and global symptoms (avoid insoluble fiber like wheat bran which worsens symptoms). 1
  • Low FODMAP diet as second-line dietary therapy, supervised by a trained dietitian. 1

• Antispasmodics: Effective for global symptoms and abdominal pain, particularly when symptoms are meal-related, though dry mouth, visual disturbance, and dizziness are common side effects. 1

• Probiotics: May be effective for up to 12 weeks; discontinue if no improvement (no specific strain can be recommended). 1

Second-line treatments for persistent pain:

• Tricyclic antidepressants (TCAs): The most effective second-line treatment for abdominal pain in IBS. Start with low-dose amitriptyline 10 mg once daily, titrate slowly to maximum 30-50 mg once daily. These work as gut-brain neuromodulators and require careful explanation to patients about rationale and side effects. 1

• SSRIs: Alternative if TCAs fail or are not tolerated; may be better initial choice if mood disorder is suspected (use therapeutic doses, not low doses). 1

• 5-HT3 receptor antagonists: Highly efficacious for IBS with diarrhea; ondansetron 4-8 mg up to three times daily (constipation is common side effect). 1

For Inflammatory Bowel Disease (IBD) with Acute Abdominal Pain

Multidisciplinary management is essential, involving both gastroenterology and acute care surgery. 1

Initial supportive care:

• Adequate intravenous fluid resuscitation. 1
• Low molecular weight heparin for thromboprophylaxis. 1
• Correct electrolyte abnormalities and anemia. 1

Antibiotic therapy:

• Not routinely administered unless superinfection or intra-abdominal abscess is present. 1
• When indicated, cover Gram-negative aerobic/facultative bacilli, Gram-positive streptococci, and obligate anaerobic bacilli (e.g., fluoroquinolones or third-generation cephalosporin plus metronidazole). 1

For intra-abdominal abscesses in Crohn's disease:

• Abscesses >3 cm: Percutaneous drainage is preferred as bridging to elective surgery, reducing stoma rates and limiting intestinal resection. 1
• Abscesses <3 cm: May respond to antibiotics alone, though recurrence rates are high, especially with associated fistula. 1
• Surgery indicated if percutaneous drainage fails or septic shock develops. 1

Disease-specific therapy:

• Severe active ulcerative colitis: Intravenous corticosteroids if hemodynamically stable; assess response by day 3. 1
• Non-responders: Consider medical rescue with infliximab plus thiopurine or ciclosporin in multidisciplinary approach. 1
• Penetrating Crohn's disease: Infliximab after adequate abscess resolution. 1

For Chronic Pain in IBD (Pain Persisting After Inflammation Resolves)

Recognize that chronic pain involves central sensitization mechanisms, not just peripheral inflammation. 1

Treatment approach:

• Low-dose TCAs or SNRIs as baseline neuromodulation (can be managed by gastroenterologists). 1
• Cognitive behavioral therapy for patients with insight into thought-pain relationships. 1
• Hypnotherapy for visceral hypersensitivity (requires certified clinical provider). 1
• Avoid opiates - conventional analgesia is not successful for IBS-type pain. 1

Important Caveats

• Loperamide treats diarrhea in IBS but commonly causes abdominal pain, bloating, and constipation; careful dose titration is essential. 1

• Preoperative immunomodulators, anti-TNF agents, and steroids increase risk of intra-abdominal sepsis in IBD patients requiring emergency surgery. 1

• Abdominal wall pain is frequently overlooked; suspect when pain is chronic, unrelated to eating/bowel function, related to posture, and worsens with muscle tensing (positive Carnett's sign). 3

• Elderly patients with fever and abdominal pain require heightened suspicion as laboratory tests may be normal despite serious infection. 1