AAA – and it is not related to the car rescue service!

AAA risk factors

In order to further my knowledge on AAA’s, I found an interesting article in the Journal of Orthopaedic & Sports Physical Therapy to read.

I have extracted some of the main points relevant to AAA detection and added some additional info and videos links.

This is a rare issue but can present itself as lower back pain. As physios, we are often the first medical professional a patient may present to with an issue. A general awareness of the AAA risk factors and being able to perform a basic screening will enable us to refer on any patients we are concerned about, for immediate ultrasound scanning.

Thanks for reading,


Annika Williams

Senior Physiotherapist

J. Wyngaarden et al, Abdominal Aortic Aneurysm in a patient with lower back pain – A Resident case problem.

Journal of Orthopaedic & Sports Physical Therapy, 2004 Vol. 44, Issue 7, p.500-7. 


The Purpose:
To describe the clinical reasoning that led a clinician to identify an abdominal aortic aneurysm (AAA) in a patient with low back pain. To provide an evidence-based approach to clinical evaluation of patients with suspected AAA.

The Outcome:
The concluded that  knowledge of the risk factors for AAA, understanding how to screen for nonmusculoskeletal symptoms, basic competence in abdominal palpation and how to interpret findings will all help with a physio’s clinical decision making.
This should ultimately help identify patients who should be referred for further testing.

Only 1-2 % of LBP is due to visceral disease or a non-mechanical pathology.  One type of visceral disease that may cause low back pain is AAA.

What is an AAA?
An aneurysm is a permanent and irreversible dilation of a blood vessel over 50% its normal size.  An AAA occurs in a weakened or diseased arterial wall. An infrarenal aorta that is >3 cm in diameter is considered aneurysmal. The diameter of the infrarenal aorta is the strongest known predictor of risk for rupture, with the risk substantially increasing with infrarenal aorta diameters of  > 5.0 cm.

The main signs and symptoms to be aware of in AAA:

  • Night pain
  • No specific mechanism of injury
  • The patient being unable to find a position of comfort
  • Unchanging symptoms during the physical examination
  • Abnormal abdominal palpation

AAA Risk Factors:

  • Atherosclerosis
  • Increased blood pressure
  • Males
  • 60 years +
  • Coronary heart disease
  • COPD
  • Statin use
  • Previous history of smoking
  • A genetic history of AAA

Abdominal palpation:
Patient lies in crook lying with a relaxed abdomen.  Look and palpate over the 4 sections of the abdomen for any changes in tone, skin colour, lumps or tender areas. The aortic pulse can be palpated with your index fingers just left and superior to the umbilicus.  Placing both hands palm down on the abdomen, track your 2 index fingers to the sides of the aorta until you feel the pulse weaken. This measurement should be under 3cm.

Points to consider:

  • This is a safe screen and it not associated with any increased risk of AAA rupture
  • If a palpable pulsation of over 3cm is noted, onward referral for an ultrasound is indicated
  • It is hard to actually detect AAA’s under 5cm!
  • Accuracy will depend on the patients abdominal girth;
  • The sensitivity of palpation in patients with an abdominal girth less than 100 cm and an AAA 5.0 cm or greater is 100%. (Fink HA, Lederle et al. The accuracy of physical examination to detect abdominal aortic aneurysm. Arch Intern Med. 2000;160:833–836.)
  • The NHS now offers routine screening for men over 65 years.

Full Article:

YouTube video on basic AAA explanation:

YouTube Video on finding the abdominal aorta:

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