Acute ischaemia: Lower limb Flashcards Preview

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Flashcards in Acute ischaemia: Lower limb Deck (21):
1

Define acute limb ischaemia

Any sudden decrease in limb perfusion that causes a potential threat to liability. Features of severe ischaemia <2wk duration.

2

What are the signs and symptoms of acute limb ischaemia?

6 Ps:
Pain (early)
Pallor (initial), Mottling (later)
Pulselessness
Paraesthesia (early)
Paralysis (advanced)
Perishingly cold

3

Name 2 complications of acute limb ischaemia

Limb loss (40%)
Death (20%)

4

What occurs if arterial circulation is not restored within 6 hours of onset of acute limb ischaemia?

Extensive tissue necrosis

5

What skin colour changes are seen with acute limb ischaemia? Explain their appearance

Initial: Pallor due to arterial spasm, causing insufficient arterial perfusion.

Later: Mottling (blue/purple reticular pattern) as skin fills with deoxygenated blood.

6

Describe the aetiology of acute lower limb ischaemia

Acute thrombosis in vessel with atherosclerosis (60%)

Emboli (30%)

Rare: aortic dissection, trauma, iatrogenic injury, popliteal aneurysm, intra-arterial drug use

7

Name 2 predisposing factors for acute thrombosis leading to acute limb ischaemia

Dehydration
Hypotension
Malignancy
Polycythaemia (XS RBC)
Inherited prothrombotic states

8

What clinical features are suggestive of acute thrombosis as the cause of acute limb ischaemia?

Previous Hx of intermittent claudication
No obvious embolic source
Reduced/absent pulses in contralateral limb

9

What is the commonest thrombotic cause of acute limb ischaemia?

Atherosclerosis

10

What are the embolic causes of acute limb ischaemia?

Cardiac (80%): AF, MI, ventricular aneurysm

Arterial aneurysm (10%)

Embolism of atherosclerosis in limb (rare)

11

What clinical features are suggestive of acute embolism as the cause of acute limb ischaemia?

Sudden onset of symptoms
Known embolic source
Absence of previous intermittent claudication
Normal pulses in contralateral limb

12

What investigations should be done in acute limb ischaemia?

FBC, U&E, clotting, glucose, troponin
Group and save
ECG - AF
ECHO - structural heart defects/ventricular aneurysm
CT - thrombus, emboli, dissection, aneurysm
Tumour markers

May consider Duplex USS or angriogram to locate stenosis.

13

Outline emergency treatment of acute limb ischaemia

100% oxygen
IV access - consider fluids if hypotensive
5-10mg morphine IM
Call for senior help

IV heparin (5000IU bolus + 1000IU/h infusion)

Start treatment for associated cardiac conditions (AF/CCF etc.)

14

Describe clinical features of irreversible acute limb ischaemia

Fixed mottling of skin
Petechial (small red/purple spot) haemorrhages in skin
Woody hard muscles

15

Describe clinical features of acute limb ischaemia that requires immediate treatment

Muscles tender/swollen on palpation
Loss of power
Loss of sensation

16

Describe clinical features of acute limb ischaemia that requires prompt treatment after investigation

Pulselessness
Pale
Cold
Reduced capillary refill

17

What is the definitive treatment of irreversible acute limb ischaemia?

Amputation

18

What is the definitive treatment of acute limb ischaemia that requires immediate treatment?

Revascularise limb
Fasciotomy - treat and prevent compartment syndrome
Consider amputation

19

What is the definitive treatment of acute limb ischaemia that requires prompt treatment after investigation?

Continue heparin
Angiogram or Duplex USS - locate disease
Thrombolysis/angioplasty/arterial surgery or all

20

How can the acute limb ischaemia be categorised following limb viability assessment?

Irreversible
Requires immediate treatment
Requires prompt treatment after investigation

21

What is a complication of revascularisation for acute limb ischaemia? How is this treated and prevented?

Reperfusion injury causing:
-Compartment syndrome
-Muscle necrosis

Treatment and prevention involves fasciotomies.