Why it matters
Back pain is one of the most common complaints in the ED — usually benign. But hidden among the muscle strains and sciatica is the abdominal aortic aneurysm (AAA). Missing it means sending a patient home who could rupture and die within hours. Every rookie must learn: not all back pain is musculoskeletal.
1) The 30-second story
- Older male (typically >60), smoker, hypertensive.
- Sudden onset abdominal, flank, or back pain.
- May have syncope or collapse.
- Hypotension in the setting of back pain is AAA until proven otherwise.
2) Quick differential
- Vascular: AAA, aortic dissection.
- GI: pancreatitis, peptic ulcer, cholecystitis.
- GU: renal colic, pyelonephritis.
- MSK: lumbar strain, herniated disc.
- Other: spinal epidural abscess/hematoma.
3) Red flags 🚨
- Hypotension, syncope, or shock with back/abdominal pain.
- Pulsatile abdominal mass.
- Sudden severe pain, often described as “tearing” or “ripping.”
- Older age, male sex, smoker, vascular disease.
- Collapse in the waiting room after walking in with “back pain.”
4) Bedside exam & first steps
- Vitals: tachycardia, hypotension.
- Abdominal exam: pulsatile mass (only ~50% palpable).
- Back exam: tenderness is nonspecific — don’t get fooled.
- POCUS: game changer — can rapidly detect AAA at bedside (aortic diameter >3 cm is abnormal).
5) Investigations
- Bedside ultrasound: fastest, most practical ED test.
- CT angiography: gold standard for diagnosis in stable patients.
- Labs: CBC, type & cross, coagulation panel, renal function.
- Don’t delay transfer/surgery for labs if patient is crashing.
6) Management in the ED
- Unstable patient (suspected ruptured AAA):
- Call vascular surgery immediately.
- Large-bore IV access, permissive hypotension (SBP ~80–90 mmHg until surgical control).
- Massive transfusion protocol if needed.
- Avoid aggressive fluid resuscitation — worsens bleeding.
- Prepare for emergent OR.
- Stable patient (suspected AAA, no rupture):
- Pain control, BP control (labetalol/esmolol for dissection suspicion).
- Arrange CT angiography.
- Consult vascular surgery urgently.
7) Disposition
- Ruptured AAA: straight to OR/vascular surgery.
- Large but intact AAA: admit for repair (endovascular or open).
- Small incidental AAA (<5 cm, asymptomatic): outpatient vascular follow-up.
Rookie pearls
- Back pain + hypotension + older male = AAA until proven otherwise.
- Bedside ultrasound is the fastest, most powerful tool for rookies.
- Don’t get distracted by “renal colic” — AAA can mimic it.
- Permissive hypotension saves lives — don’t over-resuscitate.
- A negative abdominal exam does not rule out AAA.
Common pitfalls
- Discharging an older patient with back pain without considering AAA.
- Missing AAA in women (less common but often deadlier).
- Ordering CT without checking stability first — unstable = to OR, not scanner.
- Overloading with fluids — can blow the clot and worsen rupture.
- Anchoring on musculoskeletal pain in a high-risk patient.
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