What is the most appropriate initial step in management for a patient with severe pelvic and back pain, transient hypotension, and free fluid in the lower abdomen after a roll-over accident?

Management of Trauma Patient with Pelvic Pain, Hypotension, and Positive FAST

The most appropriate initial step is CT of abdomen and pelvis with IV contrast (Option C), as this patient is now hemodynamically stable (BP 100/60 after fluid resuscitation) and requires complete injury inventory to identify all bleeding sources and guide definitive management. 1, 2

Hemodynamic Status Assessment

This patient's current hemodynamic status is the critical decision point:

• Initial transient hypotension was successfully managed with 500 mL NS bolus in the ambulance 3
• Current BP of 100/60 indicates relative stability, allowing safe transport to CT scanner 3, 1
• The patient responded to initial resuscitation, which shifts management toward comprehensive imaging rather than emergent intervention 4, 2

Why CT with Contrast is the Priority

In hemodynamically stable trauma patients, contrast-enhanced CT provides:

• Complete inventory of all injuries including hepatic, splenic, renal, and pelvic vascular injuries 3
• 93.9% positive predictive value and 87.5% negative predictive value for detecting active bleeding compared to angiography 3, 1
• Identification of solid organ injuries that may be the source of free fluid seen on FAST 3, 4
• Detection of retroperitoneal hemorrhage, which FAST cannot reliably exclude 3
• Superior diagnostic performance with sensitivity of 98% and specificity of 98% for solid organ lesions 3

Why Other Options Are Inappropriate

Pelvic X-ray (Option A) should not delay CT in stable patients:

• Pelvic X-ray adds no clinical value when CT is accessible and the patient is stable 3, 2
• CT identifies 35.6% more pelvic fractures than plain radiography 2
• In stable patients, pelvic X-ray does not influence management since CT provides superior information 3

Retrograde urethrogram (Option B) is not indicated as initial management:

• Urethral imaging is only recommended when specific clinical symptoms are present: inability to urinate, gross hematuria, blood at the meatus, or suprapubic tenderness 3
• This patient has no documented urethral injury symptoms 3
• Systematic urethral imaging is not warranted as these injuries never jeopardize outcome in the initial phase 3

Back MRI (Option D) has no role in acute trauma:

• MRI is contraindicated in unstable trauma patients and provides no advantage over CT for acute bleeding detection 1, 2
• CT provides faster, more comprehensive evaluation of all potential injury sources 3, 1

Clinical Algorithm for This Patient

1. Confirm hemodynamic stability (BP 100/60 after resuscitation indicates stability) 1, 2
2. Proceed directly to contrast-enhanced thoraco-abdomino-pelvic CT without delay for plain radiographs 3, 1, 2
3. Use portal venous phase imaging as standard protocol for optimal solid organ injury characterization 1
4. Consider arterial phase if active arterial bleeding or pseudoaneurysm needs assessment 1
5. Based on CT findings, determine need for angiography/embolization, surgical intervention, or non-operative management 3, 4

Critical Pitfalls to Avoid

• Do not delay CT to obtain pelvic X-rays in stable patients—this adds unnecessary time without clinical benefit 3, 2
• Do not perform noncontrast CT—this significantly reduces sensitivity for vascular and visceral injuries 1
• Do not assume FAST-positive fluid is only from pelvic injury—free fluid may represent hepatic, splenic, or other solid organ bleeding requiring different management 3, 4
• Do not proceed to retrograde urethrogram without specific urethral injury symptoms—this delays definitive diagnosis and is not indicated systematically 3