Friday, February 4, 2011

CASE STUDY : Abdominal Aortic Aneurysm

1 - Presenting Complaint:[i1]

A 71-year-old male, referred by his GP for investigation and management of 1 month history of intermittent back pain.

background history : Hypertension, hypercholesterolemia and coronary bypass 20 years ago[i2]

2 - History of Presenting Complaint:

S- lumbosacral region

R-radiates to posterior left leg

C-dull achy sensation but was sharp at times

O-since 4 weeks ago, no previous similar episodes

P-intermittent

D- varies in duration.
S-5-7/10 in severity ( angina- the most pain )
A- low back movement, standing, sitting and driving
R- partially relieved by Tramadol
A- no morning stiffness, no bowel/ bladder problem, no lower limb weakness or tingling sensation, no weight loss or fever, not involving in recent heavy lifting. Walking was not interrupted
[i3]

Prior to his presentation, the patient had been in bed for a period of two weeks following a diagnosis of lumbosacral sprain and prescription of bed rest and heat application by his GP.

3 - Past Medical History:

1. MI- 20 yrs

2. HTN – 20 yrs

3. Hypercholesterolaemia- 20 yrs

4 - Past Surgical History:

1. Appendicectomy – 15 years old

2. Coronary bypass- 20 years ago

5 – Medications:

1. Atorvastatin 10mg

2. Aspirin 75 mg

3. Atenolol 100mg,

4. chlortalidone 25mg 1 tabs OD PO

5. Lansoprazole 30mg OD PO

6. Tramadol

6 - Allergies:

No known drugs or food allergies.

7 – Family History:

1. Father- died from heart attack at 60 yearsold

2. Mother-died of old age 88

8 – Social History:

1. Ex-smoker, stop smoking after having MI, smokes 40 ciggarate/ day for 40 years

2. Drink alcohol occasionally = 4 units/week

3. Pensioner, life with his wife in a single storey house.

9- System review – unremarkable

10- physical examination

On general inspection: the patient sitting comfortably at the edge of the bed. Not in any respiratory distress. Good color and well nourished. Pain free

Vital signs:

Elevated blood pressure : 140/85

respiratory rate 16 breaths/min

pulse: 68 beats/min regular and of normal volume and character

Temperature: 37ºC

O2 sat ; 98% RA

Examination of lower back:

LOOK No scars or deformities,

FEEL No tenderness/warmth on palpation

MOVE: a 50% limitation in lumbar flexion and extension at L4-S1reigon. All other ROM were normal

Lower limb neurological examination was all normal.

-normal gait,

-no muscle wasting, fasciculation,

-power 5/5 bilaterally

- reflex- normal

-coordination, proprioception, sensation were intact

Abdominal examination-

Abdomen is not distended, 5 cm well healed scar at right lumbar region

Soft and non-tender, no guarding, no rigidity

Positive finding on abdominal palpation- expansile and pulsative mass predominantly above the umbilicus.

No bruit on auscultation, bowel sound was normal.

Other GI signs were un remarkable.

CVS- sternotomy scar was present. 1st and 2nd sound were present , with pansystolic murmur, loudest at mitral area and radiate to the axilla, 3/5 in intensity- which is consistent to mitral regurgitation.

Peripheral pulses were all present and normal.

Respi- normal. Air entry is equal bilaterally, no wheeze of crepitation

Summary- this is 77 years old man, presented with one month history of lower back pain with multiple risk factors of cardiovascular disease includes, htn, hypercholesterolemia, previous MI, positive family history, and history of smoking.

Positive finding on examination include hypertension, limited range on movement at L4-S1, expansile and pulsatile abdominal mass and pansystolic murmur.

Differential diagnosis for the presentation includes :

1-AAA

2-lumbar spinal stenosis

3-lumbar spinal sprain

4-malignancy

5- degenerative ( OA)

Investigation

FBC, ESR,CRP, U+E normal

Abdominal US :

5 .5 cm AAA with intramural thrombus

XRAY of spine was normal, apart from calcification on Abdominal aorta wall

CT- 5.5cm A.P x 5 cm transversely, infrarenal abdominal aortic aneurysm, with thrombus. No evidence on leak

He is now scheduled for an EVAR[i4]

Pre-op work up

Blood : crossmatch, coagulation, LFT

Pre operative assessment:

Ø Cardiac – unstable angina, Recent MI, CCF

§ ECG, Stress Test, Echo, Coronary Angiogram

§ 70% of patients with an AAA will have significant Coronary Artery Disease

Ø Pulmonary – Respiratory reserve

§ PFT’s, CXR, ABG

Ø Renal – Cr

Imaging

q 3D reconstruction of spiral CT images

q Size/extent of aneurysm - abdominal/thoraco-abdominal

q Relation to renal arteries/involvement of iliac vessels

Discussion

Complication of EVAR :

Bleeding

q graft site

q Venous

q DIC

Respiratory

q Atelectasis

q Pneumonia

q ARDS

q Pulmonary oedema

q Pulmonary Embolism

Cardiac

q CCF

q Arrhythmias

q Ischaemia/MI- in 20%

q Myocardial Depression

Gastro-Intestinal Tract

q Mesenteric ischaemia

q Paralytic ileus

q Malnutrition

Renal

q UTI

q Renal failure- high dose nephrotoxic contrast

Lower Limbs

q Acute limb ischaemia

q Deep venous thrombosis

Wound Complications

q Infection

q Dehiscence

q Incisional hernia

Spinal Cord

q Paraplegia

Infected graft

q Pseudo-aneurysm formation

q Aorto enteric fistula

Impotence

Ischemia Reperfusion Syndrome

Follow up/ Post-Discharge plan

30 day mortality 1.7% EVAR vs 4.7% Open

15% EVAR Further Intervention

These patients require frequent and prolonged clinical and radiological follow-up, not only to monitor for endoleak, but also because there is no information on the long-term outcome of this type of repair.


[i1]PRESENTING COMP:

n Asymptomatic - 75%

n Incidental finding

q Routine examination

q Ultrasound Sound scanning/Plain Film Abdomen for other reason

q Patient notices pulsatile mass

n Symptomatic

q Distal Embolisation

(blue toe syndrome)

q Leak

(abdominal/back /flank pain)

q Rupture

(hypovolaemic shock, sudden epigastric/back pain)

q Fistulation – “Rare”

(aorto-caval/aorto-enteric)

[i2]Risk Factors :

q Smoking

q Hyperlipidaemia

q Hypertension

q Peripheral vascular disease

q Marfan Syndrome, Ehlers-Danlos syndrome

q Prevalence of AAA in siblings of patients with known aneurysm is approximately 4 times greater than in individuals with no family history

[i3]Rule out Spinal nerve compression, degenerative disease, rheumatoid, malignancy, infection, trauma

n [i4]Indications for Surgery:

q Rupture

q Symptomatic - back/flank/abdominal pain, embolisation

q Rapid increase in size >0.5 cm/year

q Asymptomatic ≥ 5.5 cm – exact lower limit controversial

q Aorto-caval/Aorto-enteric fistula

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