What are the recommended treatments for Complex Regional Pain Syndrome (CRPS) of the abdomen?

CRPS of the Abdomen: Treatment Recommendations

Complex Regional Pain Syndrome (CRPS) of the abdomen does not exist as a recognized clinical entity—CRPS is a limb-specific disorder affecting extremities after trauma or surgery, not the abdomen. 1, 2 If you are experiencing chronic abdominal pain that is centrally mediated and not responding to standard therapies, this is classified as Centrally Mediated Abdominal Pain Syndrome (CAPS), which requires an entirely different treatment approach. 3

Critical Diagnostic Clarification

• CRPS exclusively affects limbs (upper and lower extremities) following injury or surgery, with an incidence of 5-26 per 100,000 population and occurring in approximately 5% of limb injuries. 2

• Abdominal pain syndromes are not CRPS—chronic abdominal pain with central sensitization mechanisms is termed CAPS or falls under disorders of gut-brain interaction (DGBI). 4, 3

• If you have been told you have "CRPS of the abdomen," this represents a fundamental misdiagnosis that must be corrected before appropriate treatment can begin. 3

If You Have Centrally Mediated Abdominal Pain (CAPS)

First-Line Pharmacologic Treatment

• Start low-dose tricyclic antidepressants (TCAs) as first-line neuromodulator therapy, initiating amitriptyline at 10-25 mg at bedtime and titrating slowly every 1-2 weeks based on response and tolerability. 3

• Offer serotonin-norepinephrine reuptake inhibitors (SNRIs) such as duloxetine if TCAs cause intolerable side effects (dry mouth, constipation, sedation) or for more severe symptoms requiring dual-mechanism pain modulation. 4, 3

• Absolutely avoid opioids for chronic gastrointestinal pain due to CAPS, as they worsen long-term outcomes, cause narcotic bowel syndrome (paradoxical hyperalgesia), and increase morbidity without improving quality of life. 4, 3

Essential Non-Pharmacologic Interventions

• Initiate cognitive behavioral therapy (CBT) early in treatment to address catastrophizing, pain-related fear avoidance, and maladaptive cognitive processes that perpetuate central pain amplification. 4, 3

• Offer gut-directed hypnotherapy for patients with visceral hypersensitivity and somatic symptoms, delivered by certified clinical providers trained in this specific technique. 4, 3

• Consider mindfulness-based stress reduction for managing psychological stress and negative emotions that amplify pain perception through central mechanisms. 3

Critical Communication Strategy

• Establish a collaborative, empathic, culturally sensitive patient-provider relationship as the foundation of all treatment, explicitly acknowledging that the pain is real and multifactorial. 4, 3

• Explain that pain perception involves central amplification mechanisms—the brain's pain processing system requires treatment, not that pain is "all in their head" in a dismissive sense, but that neuroplastic changes in pain pathways are maintaining symptoms. 3

• Look for the "closed eyes sign" during abdominal examination (patient closes eyes during palpation), which is a behavioral indicator of centrally mediated pain mechanisms prompting a shift toward neuromodulator therapy and brain-gut behavioral interventions rather than continued investigation for organic disease. 3

Multidisciplinary Escalation for Refractory Cases

• Refer to a psychologist with chronic pain experience for patients with limited response to baseline neuromodulators and self-management, or when significant psychiatric comorbidities (anxiety, depression, trauma history) are present. 3

• Consider combination neuromodulators (augmentation) for severe refractory symptoms, such as duloxetine plus gabapentin, but monitor vigilantly for serotonin syndrome (fever, hyperreflexia, tremor, sweating, diarrhea, altered mental status). 3

If You Actually Have CRPS of a Limb

First-Line Treatment

• Physical therapy is the cornerstone and first-line treatment for CRPS, focusing on early active treatments to improve sensory perception, strength, fine motor skills, and sensorimotor integration/body perception. 1, 2

• Occupational therapy should be initiated concurrently to address functional deficits and restore participation in daily activities. 2, 5

Pharmacologic Support

• Add adjuvant analgesics (anticonvulsants such as gabapentin or pregabalin, and/or antidepressants such as amitriptyline or duloxetine) for mild to moderate cases to provide sufficient analgesia for participation in physical therapy. 1

• Opioids should only be added if anticonvulsants and antidepressants do not provide sufficient analgesia to allow participation in physical therapy, and should be prescribed responsibly with plans for discontinuation. 1

• Anti-inflammatory medications to decrease inflammation and pain in the acute phase. 2

Interventional Procedures for Moderate to Severe Cases

• Sympathetic nerve blocks are first-line interventional treatment: stellate ganglion blocks for upper extremity CRPS and lumbar sympathetic blocks for lower extremity CRPS in patients with moderate to severe pain and/or sympathetic dysfunction who cannot participate in physical therapy. 1, 6

• Spinal cord stimulation and dorsal root ganglion stimulation are the interventional procedures with the best evidence for refractory CRPS, reserved for exceptional cases and only performed in specialized centers. 2, 6

Psychological Interventions

• Stepped psychological interventions to reduce anxiety, avoidance behavior, and address neurocognitive disorders of body perception that accompany CRPS. 2, 5

Common Pitfalls to Avoid

• Do not diagnose CRPS in the abdomen—this represents a fundamental misunderstanding of CRPS pathophysiology, which is limb-specific and involves regional autonomic, sensory, and motor dysfunction following trauma. 1, 2

• Do not continue invasive testing once centrally mediated abdominal pain is established—further endoscopies, imaging, and procedures perpetuate illness behavior and delay appropriate neuromodulator and psychological treatment. 3

• Do not prescribe opioids for chronic abdominal pain due to CAPS or DGBI, as this worsens outcomes and creates narcotic bowel syndrome. 4, 3

• Do not delay referral to pain psychology—early integration of CBT or gut-directed hypnotherapy improves outcomes and prevents chronification of central pain mechanisms. 3