What is the recommended management for a patient with chronic abdominal pain and normal comprehensive metabolic panel (CMP), complete blood count (CBC), and urinalysis (UA)?

Management of Chronic Abdominal Pain with Normal Laboratory Studies

For a patient with 7 months of chronic abdominal pain and normal CMP, CBC, and urinalysis who is functioning well without weight loss, initiate low-dose tricyclic antidepressants (starting at 10-25 mg at bedtime) as first-line neuromodulator therapy while simultaneously implementing cognitive behavioral therapy and avoiding further invasive testing. 1, 2, 3

Diagnostic Completion and Red Flag Assessment

• Stop further invasive testing once basic laboratory workup (CMP, CBC, urinalysis) is normal and no alarm features are present 2, 3
• Alarm features that would warrant additional investigation include: significant unintentional weight loss, gastrointestinal bleeding, progressive dysphagia, persistent vomiting, or family history of gastrointestinal malignancy 4
• Since this patient has no weight loss and is functioning well, this suggests a functional gastrointestinal disorder rather than organic pathology 2, 4
• Consider performing Carnett's sign (increased pain with abdominal wall tensioning) to rule out abdominal wall pain, which is commonly overlooked and would change management to trigger point injections 5

First-Line Pharmacologic Management

Tricyclic antidepressants (TCAs) are the cornerstone of treatment:

• Start with amitriptyline or nortriptyline 10-25 mg at bedtime, titrating slowly every 2-3 weeks based on response 1, 2, 3
• Explain to the patient that these medications work as gut-brain neuromodulators that modulate pain processing in the spinal cord and brain, not as antidepressants for mood 1, 2
• Warn that adverse effects (dry mouth, constipation, drowsiness) occur within days, but therapeutic benefit takes 1-3 weeks 1
• TCAs have proven analgesic effects independent of mood effects in small controlled trials 1

If TCAs are not tolerated or ineffective:

• Switch to serotonin-norepinephrine reuptake inhibitors (SNRIs) such as duloxetine, which provide pain relief through descending pain modulation pathways 1, 3
• SNRIs require 2-4 weeks for efficacy and are particularly useful for more severe symptoms 1

Critical Medication to Avoid

Absolutely avoid opioids for this chronic abdominal pain, as they:

• Increase risk of addiction 1
• Cause paradoxical amplification of pain sensitivity (central sensitization) 1
• Lead to narcotic bowel syndrome with worsening pain despite escalating doses 1, 3
• Are associated with poorer long-term outcomes 1

Non-Pharmacologic Interventions (Equally Important)

Cognitive behavioral therapy (CBT) should be initiated early:

• CBT targets maladaptive cognitive processes, catastrophizing, and pain-related fear avoidance 1, 3
• Promotes patient acceptance of responsibility for change and development of adaptive behaviors 1
• Patients who do best with CBT have insight into how thoughts, feelings, and behaviors relate to their pain 1
• Strong recommendation with moderate quality evidence 1

Additional behavioral approaches to consider:

• Gut-directed hypnotherapy for visceral hypersensitivity, delivered by certified clinical providers 1, 3
• Mindfulness-based stress reduction for stress and negative emotion management 1, 3
• Physical therapy and exercise to offset negative consequences of pain on physical function 1

Communication Strategy

Establish the foundation early:

• Acknowledge that pain is real and multifactorial, involving both peripheral and central mechanisms 1, 3
• Explain that the brain's pain processing system requires treatment, not that pain is "all in their head" in a dismissive sense 1, 3
• Set expectations that disability and opioids are associated with poorer outcomes and do not reduce suffering 1
• Emphasize pain acceptance and psychological flexibility, which improve pain tolerance at the brain level 1

When to Escalate Care

Refer to a psychologist with chronic pain experience if:

• Limited response to baseline neuromodulators after 8-12 weeks 2
• Significant psychiatric comorbidities are present (anxiety, depression) 1
• Patient has history of early-life trauma, catastrophizing behaviors, or prior chronic pain 1, 3

Consider combination therapy (augmentation) for severe refractory symptoms:

• Example: duloxetine plus gabapentin 3
• Monitor vigilantly for serotonin syndrome (fever, hyperreflexia, tremor, sweating, diarrhea) 3

Common Pitfalls to Avoid

• Do not pursue repeated costly investigations once functional diagnosis is established 2, 3
• Do not dismiss pain as "functional" without appropriate evaluation and targeted treatment 2
• Do not prescribe antispasmodics as monotherapy for chronic pain; they are adjunctive for meal-related cramping only 2, 6
• Do not delay behavioral interventions while waiting for medication response; implement both simultaneously 1, 3