What is the recommended management for abdominal pain in the emergency room?

Emergency Department Management of Abdominal Pain

Begin with immediate pain control using IV opioids (morphine 0.1-0.2 mg/kg) or oral NSAIDs for mild-moderate pain, as analgesia does not impair diagnostic accuracy and should never be delayed. 1, 2, 3, 4

Initial Assessment and Stabilization

Immediate Vital Signs and Red Flags

• Assess hemodynamic stability first: Check for tachycardia, hypotension, fever, respiratory distress, or decreased urine output—these require immediate resuscitation with IV crystalloid fluids and urgent surgical consultation. 2, 5
• Obtain pregnancy test immediately in all women of reproductive age before any imaging—this is mandatory and non-negotiable. 2

Critical Pain Characteristics to Elicit

• "Pain out of proportion to exam" should trigger immediate suspicion for acute mesenteric ischemia (AMI) until proven otherwise—this is a surgical emergency with 50-80% mortality if untreated. 6
• Migratory pain from periumbilical to right lower quadrant strongly suggests appendicitis and warrants immediate CT imaging. 1
• Assess for peritoneal signs: guarding, rigidity, rebound tenderness—these indicate peritonitis requiring emergency surgical exploration. 2, 5

Laboratory Investigations

Order these tests immediately for all patients with acute abdominal pain: 2

• Complete blood count (leukocytosis suggests infection/inflammation)
• Basic metabolic panel (assess electrolytes, renal function)
• Lactate level (elevated in bowel ischemia, severe sepsis, or AMI—critical for detecting life-threatening conditions) 6, 2
• C-reactive protein (marker of inflammation, elevated CRP predicts need for hospital admission) 2, 7
• Liver function tests and lipase for right upper quadrant or epigastric pain 2

Common pitfall: Laboratory tests alone are insufficient—elderly and immunocompromised patients may have normal labs despite serious pathology. 6, 2

Imaging Strategy Based on Pain Location

Right Upper Quadrant Pain

• Ultrasound is first-line (sensitivity 81%, specificity 83% for cholecystitis). 6, 2

Right Lower Quadrant Pain (Suspected Appendicitis)

• CT with IV contrast is definitive (sensitivity >95%)—do not delay imaging in adults with equivocal findings. 6, 1, 2
• Ultrasound is preferred in children and pregnant women to avoid radiation. 3

Left Lower Quadrant Pain (Suspected Diverticulitis)

• CT abdomen/pelvis with IV contrast. 2

Diffuse or Nonlocalized Pain

• CT abdomen/pelvis with IV contrast is the imaging modality of choice—this identifies pathology across multiple organ systems. 6, 2
• Plain radiographs have limited value except for suspected bowel obstruction or free air from perforation. 6, 2

Suspected Mesenteric Ischemia

• CT angiography (CTA) should be performed immediately when AMI is suspected—this is the gold standard diagnostic test (Grade 1A recommendation). 6
• Do not wait for laboratory confirmation—elevated lactate and D-dimer may assist but are not sufficiently accurate to rule out AMI. 6

Immediate Management Decisions

Unstable Patients or Peritonitis

• Immediate fluid resuscitation with crystalloids to enhance visceral perfusion. 6, 2
• Broad-spectrum antibiotics immediately (cover gram-negative organisms and anaerobes: amoxicillin/clavulanate or ceftriaxone + metronidazole). 6, 1, 2
• Emergency surgical consultation for laparotomy if overt peritonitis, perforation, or septic shock. 6
• Anticoagulation with IV unfractionated heparin unless contraindicated, especially if AMI suspected. 6

Stable Patients with Suspected Infection

• Intra-abdominal abscesses >3 cm: Consider percutaneous drainage with antimicrobial therapy. 2
• Small abscesses <3 cm: IV antibiotics alone may suffice. 2

Special Populations Requiring Extra Vigilance

Elderly patients often present with atypical symptoms and may have normal laboratory values despite serious infection—maintain high index of suspicion and lower threshold for imaging. 6, 2

Critically ill ICU patients on vasopressors with abdominal pain or distension should be suspected of having non-occlusive mesenteric ischemia (NOMI) until proven otherwise. 6

Immunocompromised/neutropenic patients may have masked signs of abdominal sepsis—diagnosis is often delayed with high mortality. 6

Disposition Criteria

Admit to Hospital If:

• Hemodynamic instability, peritoneal signs, or suspected surgical conditions 2
• Severe pain requiring ongoing IV analgesia 3
• Inability to tolerate oral intake 3
• Elevated CRP and abnormal imaging findings (strongest predictors of need for admission) 7

Safe for Discharge If:

• Stable vital signs, tolerating oral intake, adequate pain control with oral medications 2
• Ensure 24-hour follow-up if imaging is negative but no alternative diagnosis confirmed—approximately 30% of ED abdominal pain cases remain undiagnosed. 6, 8

Critical Pitfalls to Avoid

• Never delay analgesia—pain medication does not mask symptoms or impair diagnostic accuracy; withholding pain relief is both cruel and counterproductive. 1, 3, 9
• Never rely solely on clinical exam or labs without imaging when diagnosis is unclear—imaging changes management in 51% of cases and admission decisions in 25%. 6
• Never miss the "window of opportunity" in appendicitis—delays beyond 24 hours increase perforation risk and complications. 1
• Never overlook gynecologic emergencies (ectopic pregnancy, ovarian torsion, PID) in women of reproductive age. 2
• Never discharge patients with "pain out of proportion to exam" without CTA—this is AMI until proven otherwise. 6