What is the best course of action for a patient with abdominal pain but no signs of acute abdomen?

Management of Abdominal Pain Without Signs of Acute Abdomen

For patients with abdominal pain but no signs of acute abdomen, a structured diagnostic approach with close monitoring is recommended, as these patients may still have serious underlying conditions that require intervention.

Initial Assessment

When evaluating a patient with abdominal pain but without signs of acute abdomen (no peritoneal signs, hemodynamic stability, absence of fever/tachycardia/tachypnea), consider:

• Location of pain - Guides further evaluation and imaging selection 1
• Duration and progression - Acute pain defined as lasting fewer than 7 days 2
• Associated symptoms - Vomiting, nausea, changes in bowel habits
• Risk factors - Previous surgeries (especially bariatric), immunocompromised status

Diagnostic Workup

Laboratory Tests

• Complete blood count
• C-reactive protein (CRP) and procalcitonin
• Serum electrolytes, renal and liver function tests
• Serum lactate levels
• Blood gas analysis 3

Note: High CRP levels are predictive of both early and late postoperative complications after bariatric surgery 3

Imaging Studies

Based on ACR Appropriateness Criteria:

1. Ultrasonography:

   • First-line for right upper quadrant pain 3
   • Can identify gallbladder disease, which is common after heart/lung transplantation 3
   • High negative predictive value (96.8%) for internal herniation 3

2. CT scan with IV contrast:

   • Recommended for generalized abdominal pain and lower abdominal pain 2
   • Changed the leading diagnosis in 51% of patients with abdominal pain 3
   • Essential for detecting complications such as internal hernias, small-bowel obstruction, anastomotic stenosis, perforation 3

Note: Conventional radiography has limited value in acute abdominal pain evaluation 4

Management Algorithm

For Stable Patients:

1. Close monitoring with serial abdominal examinations
2. Pain management - Opioid analgesics can be safely administered without affecting diagnostic accuracy 4
3. Consider non-operative management for patients without active peritoneal bleeding or bowel perforation 3

Warning Signs Requiring Urgent Intervention:

• Development of tachycardia ≥ 110 beats per minute
• Fever ≥ 38°C
• Hypotension
• Respiratory distress with tachypnea and hypoxia
• Decreased urine output 3

Special Considerations:

Post-Bariatric Surgery Patients

• Tachycardia is the most sensitive sign associated with surgical complications 3
• Combination of fever, tachycardia, and tachypnea is a significant predictor of anastomotic leak or staple line leak 3
• Persisting vomiting and nausea may indicate internal hernia, volvulus, gastrointestinal stenosis, intestinal ischemia, or marginal ulcer 3

Immunocompromised Patients

• May present with atypical or muted symptoms
• Higher threshold for imaging and intervention due to increased mortality risk 3
• Neutropenic enterocolitis requires broad-spectrum antibiotics and bowel rest, with surgery reserved for perforation or ischemia 3

When to Consider Surgical Exploration

1. Diagnostic laparoscopy should be considered when:

   • Clinical examination and imaging are inconclusive 5
   • Suspicion of hollow viscus injury persists 3
   • Patient has persistent poorly tolerated biloma or hemoperitoneum 3

2. Immediate surgical exploration is mandatory when:

   • Signs of shock and multi-organ failure develop
   • Peritonitis develops
   • Evidence of bowel ischemia or perforation 3

Pitfalls to Avoid

1. Delaying diagnosis - The mortality of acute abdomen increases with every hour until specific treatment is provided (2-12% mortality rate) 6

2. Overlooking common causes - Non-specific abdominal pain (24-44%), appendicitis (15-28%), and biliary disease (2-10%) are most common 5

3. Missing atypical presentations in:

   • Elderly patients - May present with normal laboratory tests despite serious infection 3
   • Immunocompromised patients - Typical signs of abdominal sepsis may be masked 3
   • Post-bariatric surgery patients - Classic signs of peritoneal irritation are usually absent 3

4. Relying solely on laboratory tests - CRP and WBC count alone are insufficient to discriminate urgent from non-urgent diagnoses 4

By following this structured approach, clinicians can effectively manage patients with abdominal pain without signs of acute abdomen, ensuring timely intervention when needed to reduce morbidity and mortality.