Abdominal Aortic Aneurysm (AAA)

This entire page is free, permanently — all seven sections. Red flag content is never gated in CliniStudy.

Who: Older adults with vascular risk. Smoking, age, male sex, family history, cardiovascular disease and hypertension are the risk signals carried by the population evidence [1].
What: A dilated abdominal aorta. Usually silent until it is found by accident, or until it leaks (Aggarwal et al. 2011).
How it behaves: Deep, constant, boring pain in the lumbar spine, abdomen, flank or groin. Sometimes a pulsating or throbbing sensation. Unchanged by posture, movement or anything you do to it.

The one thing to take from this page:

You are not diagnosing an aneurysm. You are noticing that this pain does not behave like a musculoskeletal problem — and refusing to treat it as one.

⚠️ No Australian guideline governs this decision. Anchored to the European Society for Vascular Surgery 2024 guideline [2] and the US Society for Vascular Surgery guideline [3]. Both are written for vascular surgeons choosing repair thresholds, not for a student choosing whether to refer.

Patterns > Labels. The label here is a vascular diagnosis you will never make. The pattern is non-mechanical pain in a vascular-risk patient, and that you can recognise in the first five minutes.

Five stages, in your course's order. On this pattern, BEHAVIOUR is the discriminator — which is unusual, because on most red flag patterns behaviour tells you nothing. Here, the absence of mechanical behaviour is the finding.

MAIN PROBLEM

"I've had this deep ache in my back for a few weeks and nothing shifts it."
"It's like a throbbing, right through to my front."
"It came on out of nowhere and it's just there, all the time."

BODY CHART

• P1 deep central or para-lumbar, often poorly localised and hard for the patient to outline with one finger.
• Mark the abdomen, flank and groin — not just the spine. Radiation to groin or flank is part of the pattern [4].
• Ask them to describe the quality: throbbing, pulsating, boring, deep. Those words matter here in a way they rarely do.

BEHAVIOUR

This is the section that decides it.

M / In / P / Is coding is close to useless here — and that is the point. A pain you cannot code because it does not vary is a pain that is not coming from a joint you can load.

HISTORY

• Onset without a mechanism in an older adult with vascular risk.
• Weeks of unremitting pain, or sudden severe onset. Both appear.
• Ask directly about a known aneurysm — many patients are already under surveillance and will tell you if asked.

SPECIAL / SCREENING QUESTIONS

These are not the last box on this pattern. They are the pattern.

• Smoking — current or past. The strongest modifiable risk signal in the population evidence (Altobelli et al. 2018).
• Age, sex, family history, cardiovascular disease, hypertension.
• Pulsating or throbbing sensation — ask in the patient's words, not yours.
• Collapse, syncope, sweating, feeling faint.
• Known AAA, or a relative with one.

Top three, and the single feature that separates each from this one. Rank them — then rule out the dangerous one first, even though it is the least likely.

Note what this table does not do. None of these three is excluded by anything in your hands. The ranking exists to tell you which door to knock on first, not to close any of them.

The patient with a known, stable, surveilled aneurysm and a genuinely mechanical lumbar pattern also exists — and they are allowed to have back pain like anyone else. Stay inside the vascular team's plan; treat the mechanical problem.