What is the management approach for abdominal pain?

Management of Abdominal Pain

Immediate Assessment: Acute vs. Chronic

For acute abdominal pain, obtain CT abdomen/pelvis with IV contrast after stabilizing the patient—this changes diagnosis in 51-54% of cases and alters management in 25-42% of patients. 1 For chronic abdominal pain (>3 months), focus on excluding organic disease with limited testing, then treat as functional disorder. 2, 3

Acute Abdominal Pain Management

Stabilization comes first:

• Check vital signs for fever, tachycardia, hypotension, altered mental status—these indicate potential organ failure requiring immediate IV fluid resuscitation. 1, 4
• Administer low-molecular-weight heparin for VTE prophylaxis in all acute abdominal pain patients. 1
• Provide early analgesia with NSAIDs or acetaminophen—this does NOT compromise diagnostic accuracy. 1, 4

Imaging strategy by location:

• Right upper quadrant pain: Ultrasound first-line. 2, 1, 4
• Right lower quadrant, left lower quadrant, or diffuse pain: CT abdomen/pelvis with IV contrast. 2, 1, 4
• Use single-phase IV contrast only—do NOT delay for oral contrast, as it slows diagnosis without improving accuracy. 1
• Plain radiographs have limited utility; avoid unless bowel obstruction is strongly suspected clinically. 1

Key discriminating clinical features:

• Pain migration to right lower quadrant + fever + positive psoas sign = appendicitis. 1
• Vomiting before pain onset makes appendicitis less likely. 2, 1
• Age >60 + atherosclerotic risk factors = consider mesenteric ischemia; order lactate urgently. 1
• Recent surgery = adhesive small bowel obstruction. 1

Antibiotic administration:

• Do NOT routinely give antibiotics for undifferentiated abdominal pain. 1, 4
• Give antibiotics only when: intra-abdominal abscess identified, clinical sepsis present, or specific infection confirmed. 1, 4
• For confirmed intra-abdominal infections: 4 days post-source control in immunocompetent patients; extend to 7 days in immunocompromised or critically ill. 4

Surgical consultation indications:

• Peritonitis, hemodynamic instability despite resuscitation, free air on imaging, complete bowel obstruction, mesenteric ischemia, or failed conservative management. 1, 4

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Chronic Abdominal Pain Management

For chronic abdominal pain, start with antispasmodics or low-dose tricyclic antidepressants (amitriptyline 10 mg at bedtime, titrating to 30-50 mg) after excluding organic disease—TCAs are superior to SSRIs for pain control. 2

First-Line Approach

Establish the diagnosis:

• Limited testing to exclude celiac disease, inflammatory bowel disease, and microscopic colitis is reasonable. 5, 2
• Once functional diagnosis is established, avoid repetitive testing—it increases costs without benefit and reinforces illness behavior. 5, 2

Non-pharmacologic interventions:

• Regular exercise for all patients. 2
• Soluble fiber (ispaghula) 3-4 g/day, titrating gradually; avoid insoluble fiber (wheat bran) which worsens symptoms. 2
• Low FODMAP diet as second-line dietary therapy, supervised by trained dietitian with systematic reintroduction. 2
• Do NOT recommend IgG-based food elimination diets or gluten-free diets—they lack evidence. 2

First-line medications:

• Antispasmodics (hyoscine, peppermint oil) for pain exacerbated by meals, though dry mouth, visual disturbance, and dizziness are common. 5, 2
• Loperamide 2-4 mg up to four times daily for diarrhea-predominant symptoms; titrate carefully to avoid constipation and bloating. 5, 2
• Osmotic laxatives (polyethylene glycol) or stimulant laxatives (senna) for constipation-predominant symptoms. 5

Second-Line Pharmacologic Treatment

When first-line measures fail:

• Start amitriptyline 10 mg once daily at bedtime, titrating slowly to maximum 30-50 mg daily. 2
• TCAs work as "gut-brain neuromodulators" for pain, not for depression—explain this to improve adherence. 5, 2
• TCAs are superior to SSRIs for abdominal pain based on meta-analysis data. 2
• TCAs may serendipitously help diarrhea by prolonging gut transit time. 2

Alternative second-line agents:

• Secretagogues (linaclotide, plecanatide) for constipation-predominant symptoms refractory to laxatives. 5
• 5-HT3 antagonists (alosetron) for diarrhea-predominant symptoms where available. 5

Psychological Interventions

For severe or refractory symptoms:

• Cognitive-behavioral therapy, gut-directed hypnotherapy, and relaxation techniques are effective for chronic functional pain and reduce anxiety. 5, 2
• Initiate psychological therapies early if patients are willing—they have low risk of harm and build lifelong management skills. 5
• Mental health referral is appropriate for treatment of associated psychiatric disorders (major depression, history of abuse). 5

Severe or Refractory Pain

For pain unresponsive to standard measures:

• Consider combination gut-brain neuromodulators (augmentation therapy, e.g., duloxetine plus gabapentin) with vigilance for serotonin syndrome (fever, hyperreflexia, tremor, sweating, diarrhea). 5, 4
• Refer to multidisciplinary pain center involving gastroenterology, pain management, and mental health services. 5, 2

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Critical Pitfalls to Avoid

Never use opioids for chronic functional abdominal pain—they cause narcotic bowel syndrome, dependence, gut dysmotility, serious infection risk, and increased mortality. 5, 2, 4

• Avoid repetitive CT scans without clear indication—diagnostic yield drops from 22% on initial CT to 5.9% on fourth or subsequent scans. 1
• Avoid unregulated/unproven therapies, especially those incentivized by financial gain. 5, 2
• Do not perform exhaustive testing once functional diagnosis is established—refer for psychological support instead. 3