What is the appropriate evaluation and treatment for abdominal pain in a casualty?

Evaluation and Treatment of Abdominal Pain in a Casualty

Immediate Life-Threatening Assessment

In a casualty with abdominal pain, immediately assess for hemodynamic instability (hypotension, tachycardia) and signs of peritonitis, as these indicate need for urgent surgical intervention—every 3-minute delay to laparotomy increases mortality by 1% in trauma patients with large peritoneal effusion. 1

Critical Red Flags Requiring Immediate Surgery

• Hemodynamic instability with large peritoneal effusion on FAST exam mandates immediate laparotomy 1
• Abdominal pain out of proportion to physical examination findings suggests mesenteric ischemia (mortality 30-90%) and requires immediate surgical consultation 2, 3
• Sudden onset abdominal and back pain with hypotension indicates possible ruptured abdominal aortic aneurysm (mortality >50%) 2, 3
• Signs of peritonitis (abdominal rigidity, rebound tenderness, guarding) require urgent surgical evaluation 1, 2
• Progressive hemothorax or continuous massive air leakage in thoracoabdominal trauma requires chest exploration 1

Vital Sign Interpretation

• Tachycardia is the most sensitive early warning sign of surgical complications and should trigger urgent investigation even before other symptoms develop 4
• The combination of fever, tachycardia, and tachypnea predicts serious complications including anastomotic leak, perforation, or sepsis 4
• Hypotension with abdominal pain indicates bleeding or sepsis requiring aggressive resuscitation 1, 2

Physical Examination Priorities

Specific Examination Findings

• Abdominal distension with vomiting suggests intestinal obstruction 2
• Fever with abdominal pain indicates infection or abscess 2
• Left lower quadrant tenderness suggests diverticulitis 1
• Right lower quadrant pain strongly suggests appendicitis 5
• Right upper quadrant pain suggests biliary disease 4

Critical Pitfall to Avoid

• The absence of peritoneal signs does not exclude bowel ischemia—patients may lack peritoneal findings despite established ischemia 4
• Normal lactate does not exclude internal herniation or early ischemia 4

Diagnostic Imaging Algorithm

For non-localized abdominal pain in a casualty, CT of abdomen and pelvis with IV contrast is the preferred initial imaging, altering diagnosis in 49% of patients and changing management in 42% of cases. 1, 2, 4

Imaging by Pain Location

• Non-localized or unclear diagnosis: CT abdomen/pelvis with IV contrast 1, 2, 4
• Right upper quadrant pain: Ultrasound first for suspected cholecystitis 4, 5
• Left lower quadrant pain: CT abdomen/pelvis with contrast for suspected diverticulitis 1, 4
• Right lower quadrant pain: CT abdomen/pelvis with contrast (rating 8/9) or ultrasound (rating 6/9) for suspected appendicitis 1
• Suspected vascular emergency (mesenteric ischemia, aortic dissection): CT angiography is gold standard 2, 3

Imaging Performance

• CT has sensitivity >95% for detecting diverticulitis and can identify complications (abscess, perforation, fistula) 1, 2
• CT angiography is the gold standard for diagnosing mesenteric ischemia and aortic pathologies 2, 3
• Conventional radiography has limited diagnostic value and rarely changes treatment, though useful for suspected bowel obstruction, perforated viscus, or foreign bodies 1

Laboratory Testing

Essential Initial Labs

• Beta-hCG testing is mandatory in all women of reproductive age before any imaging 4
• Complete blood count to evaluate leukocytosis 2, 4
• Elevated C-reactive protein has superior sensitivity and specificity compared to white blood cell count for confirming surgical disease 2, 4
• Elevated lactate suggests ischemia or sepsis 2
• Metabolic panel, liver function tests, amylase, and lipase 2

Laboratory Interpretation Pitfall

• Normal laboratory tests in elderly patients do not exclude serious infection—many labs may be normal despite serious pathology 4

Trauma-Specific Considerations

Penetrating Thoracoabdominal Injury

• Combined thoracoabdominal wounds require laparotomy in most cases; decision to open chest is based on intraoperative findings 1
• Closed thoracic drainage is first-line for thoracic injury unless progressive hemothorax or massive air leakage occurs 1
• Surgical delay exceeding 24 hours after bowel perforation increases mortality fourfold 1
• Two surgical teams can operate simultaneously if necessary, with rapid hemostasis as the primary focus 1

Blunt Abdominal Trauma

• In hemodynamically stable patients with blunt trauma, laparoscopic approach may be considered for diagnostic/therapeutic purposes when CT suspects diaphragmatic or hollow viscus injury 1
• FAST exam should be performed within 8-10 minutes of admission in trauma patients 1
• Non-therapeutic laparotomy rate is low (2.6%) when systolic blood pressure <90 mmHg 1

Initial Resuscitation and Treatment

Hemodynamic Support

• Primary strategy for maintaining blood pressure is ample but judicious fluid administration, including blood when indicated 1
• Dopamine and/or epinephrine in conjunction with fluid resuscitation may be preferable to norepinephrine due to tachycardic effects that counteract negative chronotropic effects 1
• Damage control resuscitation strategies should be used when necessary 1

Airway Management in Combined Trauma/Toxin Exposure

• Traumatic cervical injury must be excluded before airway manipulation 1
• Benzodiazepines are drugs of choice for sedation before intubation in these circumstances 1
• Oro- or nasopharyngeal artificial airway can be inserted before tracheal intubation to facilitate secretion removal 1

Pain Management Caution

• Abdominal pain with nausea and vomiting can result from nerve agent intoxication or pretreatment, but could also signal perforation or obstruction—primary assessment must follow Advanced Trauma Life Support principles while simultaneously treating parasympathetic signs 1

Special Population Considerations

Elderly Patients

• Elderly patients have higher likelihood of malignancy, diverticulitis, and vascular causes 4
• Symptoms may be atypical and require more extensive evaluation even if laboratory tests are normal 2, 4

Post-Bariatric Surgery Patients

• Often present with atypical symptoms; classic peritoneal signs are frequently absent 4
• Tachycardia is the most critical warning sign in this population 2

Pregnant Women

• Use ultrasound and MRI (not CT) to avoid radiation exposure 2

Surgical Decision-Making

Indications for Immediate Laparotomy

• Hemodynamic instability with large peritoneal effusion 1
• Signs of peritonitis 1, 2
• Suspected mesenteric ischemia 2, 3
• Penetrating abdominal trauma in most cases 1
• Every 10-minute delay from admission to laparotomy increases 24-hour mortality by factor of 1.5 1

Role of Laparoscopy

• In hemodynamically stable blunt trauma patients, laparoscopy may reduce non-therapeutic laparotomies and provide definitive diagnosis when clinical examination and imaging are inconclusive 1
• Exploratory laparoscopy indicated when initial CT cannot rule out hollow viscus injury 1
• Conversion rate to laparotomy varies 8.5-40%, mainly driven by technical constraints 1