Initial Approach to Abdominal Pain
The initial approach to abdominal pain should follow a systematic algorithm that prioritizes identifying life-threatening conditions first, followed by appropriate diagnostic testing based on pain location and characteristics, with CT imaging being the preferred modality for nonlocalized abdominal pain. 1
Initial Assessment
History
- Pain characteristics:
- Onset (sudden vs. gradual)
- Location and radiation
- Quality (sharp, dull, crampy, colicky)
- Severity (using pain scale)
- Timing (constant vs. intermittent)
- Aggravating/alleviating factors 2
Physical Examination
- Vital signs: Tachycardia, fever, hypotension are alarming signs requiring immediate attention 2
- Abdominal examination:
- Inspection for distension, visible peristalsis
- Auscultation for bowel sounds
- Palpation for tenderness, guarding, rigidity, rebound
- Percussion for tympany or dullness
- Specific tests (Murphy's sign, psoas sign, obturator sign)
Warning Signs Requiring Immediate Action
- Hypotension
- Tachycardia
- Fever
- Respiratory distress
- Decreased urine output
- Persistent pain despite analgesia 2
Diagnostic Algorithm Based on Pain Location
Right Upper Quadrant Pain
- First-line imaging: Ultrasonography (particularly for gallbladder pathology) 1, 2
- If inconclusive: CT with IV contrast
Right Lower Quadrant Pain
- First-line imaging: CT with IV contrast (for suspected appendicitis) 1
- For pregnant patients or young women: Ultrasound first, MRI if inconclusive 2
Left Lower Quadrant Pain
- First-line imaging: CT with IV contrast (for suspected diverticulitis) 1
Nonlocalized/Diffuse Abdominal Pain
- First-line imaging: CT with IV contrast 1
- CT demonstrates superior diagnostic yield compared to abdominal radiography 1
Pain Management
Non-opioid Options
- First-line: Antispasmodics for crampy pain, particularly when exacerbated by meals 1
- For IBS-related pain: Peppermint oil can be effective 1
Opioid Management
- When indicated: Morphine 0.1-0.2 mg/kg IV every 4 hours as needed 3
- Administration: Inject slowly to prevent chest wall rigidity 3
- Caution: Conventional analgesia with opiates is not successful for chronic pain conditions like IBS 1
Special Considerations
Pregnant Patients
- Position with left lateral tilt to prevent aortocaval compression 2
- Ultrasound should be first-line imaging (sensitivity 96.7%, specificity 85.7%) 2
- MRI without contrast when ultrasound is inconclusive 2
- Don't withhold necessary imaging due to radiation fears - untreated surgical conditions pose greater risk 2
Elderly Patients
- May present with atypical symptoms 4
- Lower threshold for imaging and surgical consultation
- Consider comorbidities when selecting analgesics
Chronic/Recurrent Abdominal Pain
- Consider functional disorders like IBS
- For chronic pain, tricyclic antidepressants (TCAs) are more effective than SSRIs for pain management 1
- Start TCAs at low doses and titrate according to response 1
Common Pitfalls to Avoid
- Relying solely on laboratory values: Normal white blood cell count doesn't exclude serious pathology
- Delaying surgical consultation: When high clinical suspicion exists despite negative imaging 2
- Overlooking abdominal wall pain: Consider this diagnosis when pain is localized to a specific point and increases with muscle contraction 5
- Premature discharge: Ensure adequate pain control and follow-up plan
- Overreliance on radiographs: Plain films have limited value in non-traumatic abdominal pain evaluation 1
When to Consider Surgical Intervention
- Peritoneal signs (rigidity, rebound tenderness)
- Hemodynamic instability
- Persistent pain despite conservative management
- Evidence of bowel obstruction or perforation
- Failure to improve within 24-48 hours of conservative management 2
Remember that CT with IV contrast is the most valuable imaging modality for most cases of nonlocalized abdominal pain, with ultrasonography being preferred for right upper quadrant pain and in pregnant patients 1, 2.