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Centrally Mediated Abdominal Pain Syndrome

This care pathway can guide primary care providers in managing patients with centrally mediated abdominal pain syndrome (CAPS). This care pathway was developed by the specialists at UHN’s Digestive Health Centre and followed the Canadian Association of Gastroenterology recommendations.

 

This care pathway includes:

  1. A focused summary of centrally mediated abdominal pain syndrome (CAPS)

  2. Primary care checklist

  3. Algorithm for CAPS

  4. Explanation of algorithm for CAPS

  5. Treatment for CAPS

  6. Resources

SUMMARY OF CENTRALLY MEDIATED ABDOMINAL PAIN SYNDROME

Centrally mediated abdominal pain syndrome (CAPS) is a disorder of gut-brain interaction (DGBI). It is characterized by continuous, nearly continuous, or frequently recurrent abdominal pain that is rarely related to gut function. It cannot be explained by any structural or metabolic disorder, and its diagnosis is based on meeting the Rome IV diagnostic criteria.

 

CAPS is considered less common than other DGBIs, such as irritable bowel syndrome. The prevalence ranges from 0.5% to 2.1% and is 1.5 to 2 times more common in women.

 

The pathophysiological hallmark of CAPS appears to be altered central processing, at the level of the brain, of pain signals originating from the gut. Evidence suggests a strong association between adverse early life events and exposure to chronic psychosocial stressors with increased reports of pain and changes in brain function in central areas of pain interpretation.

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Most patients with CAPS have consulted a physician and typically exhibit high healthcare utilization. Pain is often the patient’s central focus, and there are no consistent triggers for the pain.

ROME IV DIAGNOSTIC CRITERIA FOR
CENTRALLY MEDIATED ABDOMINAL PAIN SYNDROME

Must include all of the following:

  • Continuous or nearly continuous abdominal pain

 

  • No or only occasional relationship of pain with physiological events (e.g. eating, defecation, or menses)

 

  • Pain limits some aspect of daily functioning

 

  • The pain is not feigned

 

  • Pain is not explained by another structural or functional GI disorder or other medical condition

 

Criteria fulfilled for the last 3 months with symptoms onset at least 6 months before diagnosis

PRIMARY CARE CHECKLIST

  • The patient meets the diagnostic criteria for CAPS, and symptoms are not associated with systemic disease.

  • Absence of alarm features:

    • anemia, iron deficiency, GI bleeding

    • acute or unintentional weight loss

    • persistent diarrhea or vomiting

    • celiac disease or inflammatory bowel disease

    • new onset of symptoms after 50

    • abnormality on physical examination

  • Pain is not associated with bowel movements, eating, menses, or gynecological disorders.​

  • Baseline labs to rule out other potential causes: CBC, C-reactive protein

ALGORITHIM FOR CAPS

Suspected CAPS

Meets Rome IV Diganositic criteria for CAPS

AND

Symptoms not associated with systemic disease

Pain is the central focus

YES

Consider referral to GI for further work-up

YES

ALARM FEATURES noted during history and/or physical assessment?

Refer patient to a mental health care professional, if appropriate

YES

Pain is linked to bowel movements, eating, or menses.

Pain is associated with urinary or gynecological disorders (e.g. surgery)

YES

NO

Abdominal pain associated with bowel movements, consider IBS.

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Exclude any structual GI disease and other urinary or gynecological disorders (e.g.endometriosis) 

Inconsistent pain history or frequent requests for narcotics for pain with no identifiable cause

NO

Centrally-Mediated Abdominal Pain Syndrome

EXPLANATION OF ALGORITHIM FOR CAPS

The duration of symptoms is of great importance. The diagnostic approach for patients with acute abdominal pain will be completely different from those with chronic abdominal pain.

Evaluation should consist of:

  • History of symptoms that includes assessment for alarm features

  • Psychosocial assessment

  • Observation of symptom-reporting behaviours

  • Limited investigations

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Tests to exclude other diagnoses should not be done on a routine basis if there are no alarm features. The patient should be referred for further workup if alarm features are present during the assessment. In the absence of alarm symptoms, no further tests are indicated if the patient meets the diagnostic criteria for CAPS.

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Pain History

A focused pain history is crucial. Pain in CAPS is constant, nearly constant, or frequently recurring and happens more or less every day. Pain is severe and associated with impaired daily functioning (e.g. work and school absenteeism, limitations in social activities). Pain is not or is only occasionally related to physiological events, such as bowel movements, eating, and menses. Patients with CAPS often describe pain in emotional terms and involve a sizeable anatomical area rather than a precise location. There are frequent complaints of extra-intestinal symptoms (e.g. musculoskeletal pain, fatigue), and there may be a continuum of painful experiences beginning in childhood or recurring over time.

 

Presence of Other Medical Diagnosis

Symptoms compatible with CAPS may coexist with chronic pain conditions such as fibromyalgia, migraines, chronic pelvic pain, etc.

 

Concurrent Psychosocial Features and Clinical/Psychosocial Assessment

Many patients with CAPS fulfill diagnostic criteria for psychiatric diagnoses such as anxiety, depression, and somatization. A history of unresolved losses (e.g. death of a loved one, surgery), sexual and/or physical abuse are common features in patients with CAPS. However, a positive history is not diagnostic for CAPS. Instead, it can explain the development and severity of the condition. Symptoms frequently worsen soon after these events and recur on their anniversaries or during periods that may remind the patient of these events.

Questions Supporting the Diagnosis of CAPS

  • What is the patient's understanding of their condition?

  • What is the patient's history with illness?

  • What is motivating the patient to seek care now?

  • Has the patient experienced any traumatic life events?

  • Does the patient have an associated psychiatric history or diagnosis?

  • Does the pain significantly impact activities of daily living or quality of life?

  • Are there psychosocial impairments and access to resources?

  • Does the family culture influence the patient's perception of pain?

Physical Assessment

There are certain physical findings to help support the diagnosis of CAPS, but none are sensitive or specific to the condition. Abdominal palpation should begin at the area furthest from the perceived site of maximum intensity.

TREATMENT FOR CAPS

The management of CAPS relies on:

  1. Establishing an effective patient-provider relationship

  2. Following a general treatment plan.

    • setting realistic foalds

    • individualized treatment based on symptom severity

  3. Offering combination treatment options, including pharmacological and/or psychological treatments

 

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Establishing an Effective Patient-Provider Relationship  

Patients and health care providers must share responsibility for the treatment. Treatment should focus on facilitating adaptation to symptoms to improve function. When patients are ready to take an active role in their care, this is often associated with better clinical outcomes.

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Pharmacological Management

Treatment should be based on symptom severity and degree of functional impairment. If pain is severe, a trial of neuromodulators (e.g. TCAs, SNRIs) can be helpful. It may take 8 to 12 weeks to see maximal benefits. If initial dosing is ineffective, attempt to optimize dosing before moving on to another class of medications is suggested. 

Most analgesics (e.g. NSAIDs) offer little benefit because their actions are somatic in location. Narcotic analgesics should be avoided because of the risk of GI effects and worsening pain associated with CAPS.

MEDICATION
SIDE EFFECTS
RECOMMENDED DOSE

Psychological Support

Combining medical and psychological treatments can be very effective in managing symptoms. Identify when it is appropriate to refer to a mental health professional. Psychological treatments improve higher levels of brain functioning (coping, reappraising of maladaptive cognitions, and cognitive adaptation), thereby improving medication adherence. Conversely, taking an antidepressant can enhance the efficiency of the work of therapy if needed. Recommended treatments that have shown promise include cognitive-behavioural therapy, mindfulness-based therapies, hypnotherapy, and psychodynamic-interpersonal therapy.

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Integrated Care

If accessible, patients with CAPS may benefit from working with a multidisciplinary team that involves primary care providers, gastroenterologists, psychiatrists, psychologists, and other allied health members. This approach provides a holistic approach to managing and integrating the patient’s care.  

RESOURCES

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