Acute ischaemia: Lower limb Flashcards

1
Q

Define acute limb ischaemia

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the signs and symptoms of acute limb ischaemia?

A
6 Ps:
Pain (early)
Pallor (initial), Mottling (later)
Pulselessness
Paraesthesia (early)
Paralysis (advanced)
Perishingly cold
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name 2 complications of acute limb ischaemia

A
Limb loss (40%)
Death (20%)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

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

A

Extensive tissue necrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

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

A

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

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the aetiology of acute lower limb ischaemia

A

Acute thrombosis in vessel with atherosclerosis (60%)

Emboli (30%)

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

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

A
Dehydration
Hypotension
Malignancy
Polycythaemia (XS RBC)
Inherited prothrombotic states
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

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

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the commonest thrombotic cause of acute limb ischaemia?

A

Atherosclerosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the embolic causes of acute limb ischaemia?

A

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

Arterial aneurysm (10%)

Embolism of atherosclerosis in limb (rare)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

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

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What investigations should be done in acute limb ischaemia?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Outline emergency treatment of acute limb ischaemia

A

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.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe clinical features of irreversible acute limb ischaemia

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe clinical features of acute limb ischaemia that requires immediate treatment

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

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

A

Pulselessness
Pale
Cold
Reduced capillary refill

17
Q

What is the definitive treatment of irreversible acute limb ischaemia?

A

Amputation

18
Q

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

A

Revascularise limb
Fasciotomy - treat and prevent compartment syndrome
Consider amputation

19
Q

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

A

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

20
Q

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

A

Irreversible
Requires immediate treatment
Requires prompt treatment after investigation

21
Q

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

A

Reperfusion injury causing:

  • Compartment syndrome
  • Muscle necrosis

Treatment and prevention involves fasciotomies.