If someone presents with signs and symptoms of renal colic above the age of 40 without previous history of renal stones they have an AAA until proven otherwise
Presents as a triad of :
Abdominal or Back Pain of sudden onset
Collapse or Light-headedness
Hypotension
- An abnormal blood-filled dilatation of a blood vessel (especially in an artery resulting from disease of the vessel wall).
- An Abdominal Catastrophe with up to 30% misdiagnosed initially.
- Abdominal aorta begins at the level of the aortic hiatus of the diaphragm at T12
- Surface anatomy = Xiphoid sternum (dilated aorta palpable above the umbilicus)
- The dilatation is part of a generalized atherosclerotic process
- An aneurysm is defined as a focal increase in the diameter (normal 2cm) of a vessel to greater than 50% of normal; anything less is considered arteriomegaly.
Risk factors
- Male
- Age (biological age)
- Smoking
- Hypertension
- FHx
- Hypercholesterolaemia
- Peripheral Vascular Disease
- Surprisingly diabetes in protective against AAA
Presentation
Sudden Pain
- Back / Abdomen / Flank
- Inguinal / Testicular
Collapse (Light-headedness)
Aortocaval fistula
- High output cardiac failure
- Pulmonary oedema (flash)
- Leg congestion and swelling
Examination
- Unwell
- Hypotensive
- Diaphoretic
- SOB
- Abdominal Mass (Pulsatile and Expansile)
Initial Mx
Surgical On-Call when Dx suspected
Aim for Stable HYPOtension in resuscitation’ – Rodgers
Management/Investigations in ED:
IVC – 14G/16G Cannula
IVF – See above
Bloods – FBC/U&E/Coag/GxCM 6 Units
ECG – MI?, Prognosis
Investigations:
Group Xmatch x6
FBC, U&E, Creat, Coag
ECG
ECG (Hardman Criteria)/AMI
Urinalysis - UOB negative
U/S Aorta (bedside)
CT Abdomen - Takes only if stable
Differential Diagnosis:
Perforated Viscus
Aortic Dissection
Myocardial Infarction
Ureteric Colic
Neurogenic Back Pain
Mechanical Back Pain
Discitis
Surgical Prognosis Determined by:
Hardman Criteria:
Age - > 76Hb - <9.0 g/dlCreat >190mmol/lHx of LOCIschaemia on ECG |
+3 = 100% Mortality +2 = 72% Mortality +1 = 37% Mortality |
Additional Management:
Urinalysis - Qualitative Microscopic Haematuria
Urinary Catheter - Monitor Urinary Output
ABG - Acid/Base Status, Lactic Acid (bowel?)
Erect CXR - Free Air?
AXR not useful but may show loss psoas shadow
- Approximately 90% (of AAA) are infrarenal.
- The average increase is 2 mm/yr diameter.
- Usually not repaired until they exceed 4-5 cm.
- Risk of rupture within 5 years is 25% at 5 cm diameter.
- AAA > 5 cm have a 3% risk of rupture over 10 years.
References :
Medline Plus Online Medical Dictionary
Shein, M. and Rogers P. Schein’s Common Sense Emergency Abdominal Surgery 2nd Ed. Springer New York : 2005
Cameron, J Ed. Current Surgical Therapy 8th Ed. Elsevier/Mosby Philadelphia PA : 2001