What is the initial assessment and management for abdominal pain?

Initial Assessment and Management of Abdominal Pain

The initial evaluation of a patient with abdominal pain should follow a step-up approach beginning with clinical assessment and laboratory tests, progressing to appropriate imaging based on pain location, with management decisions guided by the severity of presentation and suspected diagnosis. 1

Initial Clinical Assessment

• Immediately evaluate vital signs to detect concerning features such as tachycardia, fever, hypotension, or respiratory distress, which are alarming signs requiring prompt intervention 1
• Determine pain characteristics including location, onset, duration, quality, radiation, and aggravating/alleviating factors to help narrow the differential diagnosis 1, 2
• Perform a complete abdominal examination including inspection, auscultation, percussion, and palpation to identify specific findings such as distension, tenderness, guarding, or rebound tenderness 1
• Look for alarm signs such as severe pain, sudden onset, high fever, abdominal distension, rebound tenderness, or a positive Murphy's sign (pain when pressing the right upper quadrant) 2

Laboratory Investigations

• Complete blood count to evaluate for leukocytosis, suggesting infection or inflammation 1, 2
• Consider liver function tests and hepatobiliary markers, especially for right upper quadrant pain 1
• C-reactive protein as a marker of inflammation, and serum electrolytes, creatinine, and blood urea nitrogen to assess renal function 1
• Pregnancy test is mandatory for all women of reproductive age with abdominal pain before proceeding to imaging 1, 2
• Lactate levels can be used to assess for bowel ischemia or severe sepsis in patients with abdominal pain 1

Imaging Studies Based on Pain Location

• Right upper quadrant pain: Ultrasonography is the initial imaging test of choice, with a sensitivity of 81% and specificity of 83% for cholecystitis 1, 2
• Right lower quadrant pain: CT scan with contrast is recommended, with a sensitivity of over 95% for appendicitis 1, 3
• Left lower quadrant pain: CT scan with contrast is recommended, especially for suspected diverticulitis 1, 2
• Diffuse or nonlocalized abdominal pain: CT scan with IV contrast is preferred as the initial imaging method 1, 3
• Pelvic pain: CT of abdomen and pelvis with contrast is the most appropriate initial imaging method 1, 2
• Suspected kidney stones: Non-contrast CT of the abdomen and pelvis 1, 2

Management Approach

• Hemodynamically unstable patients require immediate resuscitation with intravenous fluids and surgical consultation 1
• Patients with signs of peritonitis, perforation, or septic shock require emergency surgical exploration 1
• For stable patients with suspected intra-abdominal abscesses >3cm, consider percutaneous drainage with antimicrobial therapy 1, 3
• Small abscesses (<3cm) without evidence of fistula and no steroid therapy may be treated with intravenous antibiotics alone 3
• Antibiotics should not be routinely administered but are indicated for suspected infection or intra-abdominal abscess 3, 1
• When antibiotics are needed for intra-abdominal infections, they should cover Gram-negative bacteria and anaerobes 3, 4

Special Considerations

• Elderly patients often present with atypical symptoms and may have normal laboratory tests despite serious pathology 1, 2
• In women of childbearing age, consider gynecologic conditions such as ectopic pregnancy, ovarian torsion, or pelvic inflammatory disease 1, 2
• Immunocompromised patients may have masked signs of abdominal sepsis 1
• For pregnant patients, ultrasound should be the first-line imaging, with MRI preferred over CT if additional imaging is needed 1
• Patients with inflammatory bowel disease presenting with acute abdominal pain require multidisciplinary management involving a gastroenterologist and an acute care surgeon 3

Disposition Decisions

• Patients with severe pain, hemodynamic instability, peritoneal signs, or suspected surgical conditions require hospital admission 1
• For patients with chronic abdominal pain without red flag features, consider functional disorders after organic pathology has been confidently excluded 5

Common Pitfalls to Avoid

• Relying solely on laboratory tests without appropriate imaging, as many conditions require imaging for definitive diagnosis 1
• Delaying surgical consultation in patients with peritonitis or signs of septic shock 1
• Overlooking gynecological causes in women of reproductive age 1, 2
• Failing to recognize that elderly patients may present with atypical symptoms 1, 2
• Overusing CT scans in young patients, increasing unnecessary radiation exposure 1, 2
• Plain radiographs have limited diagnostic value and should not be routinely used, except in cases of suspected bowel obstruction 1