Acute Limb Threat

Question 1

Define acute limb ischaemia.

Answer 1

sudden loss of blood supply to a limb - occlusion of native artery or bypass graft

Question 2

What is the essential thing to distinguish between in acute limb ischaemia?

Answer 2

acute ischaemia vs acute on chronic ischaemia

Question 3

Name some causes of sudden occlusion?

Answer 3

embolism, athero-embolism, arterial dissection, trauma, extrinsic compression

Question 4

What are the clinical features of acute limb ischaemia? (6 Ps)

Answer 4

Pain - excruciating pain as some as blockage forms
Pallor - sheet white
Pulseless - distal to block
Perishingly cold
Paraesthesia - tingling sensation
Paralysis - if left too long

Question 5

What needs to be checked when talking a history/examination of acute limb ischaemia?

Answer 5

No prior history of claudication
Known cause for embolism (mostly cardiac)
Full complement of contra-lateral pulses

Question 6

What does a ‘woody’ compartment indicate in a calf/muscle?

Answer 6

muscle necrosis

Question 7

What does blanching mottling indicated in a limb?

Answer 7

capillaries have refilled with stagnated deoxygenated blood -> mottled appearance (purple-ish)
= ischaemia is partially reversible

Question 8

What does a non-blanching limb indicate?

Answer 8

irreversible ischaemia

arteries distal to occlusion have filled with propagated thrombus with rupture of capillaries

Question 9

Is a limb salvageable once paraesthesia/paralysis sets in?

Answer 9

only if prompt re-vascularisation

Question 10

What happens if you transfuse a patient blood if they have had acute limb ischaemia >12hrs?

Answer 10

kills the patient since perfusion attempt has circulated all the bad stuff from the dead tissue

Question 11

How would you manage an acute limb ischaemia?

Answer 11

ABC resuscitation and investigation.
FBC, U&E, CK, Coag ± troponin
Anti-coagulate

Question 12

Why could an underlying malignancy be the cause of acute limb ischaemia?

Answer 12

(adenocarcinoma) patient will be pro-thrombotic

Question 13

Which tests would you do in management of acute limb ischaemia?

Answer 13

ECG - MI, dysarrhythmia
CXR - underlying malignancy
Arterial imaging (only if not certain it is due to an embolus) - CT/catheter angiogram

Question 14

What are the methods of clearing/dissolving a clot?

Answer 14

Embolectomy - clearing out clot
Fasciotomy - to avoid compartment syndrome
Thrombolysis

Question 15

What is the triad of diabetic foot sepsis?

Answer 15

tissue ulceration
necrosis
gangrene

Question 16

Where do neuro-ischaemic ulcers occur?

Answer 16

areas of raised pressure i.e. under metatarsal heads

Question 17

Where might the source of sepsis be in diabetic foot sepsis?

Answer 17

simple puncture wound
infection from nail plate/inter-digital space
from a neuro-ischaemic ulcer

Question 18

Why is infection a big problem if in the foot?

Answer 18

intrinsic digit muscles are contained in rigid compartments; if infection gets into these compartments; pus can’t escape, raised pressure impairs capillary flow; infection and tissue damage builds up quickly and become septic

Question 19

What are the foot compartments bound by?

Answer 19

plantar fascia
metatarsal bones
interosseous fascia

Question 20

What would be the clinical findings in diabetic foot sepsis?

Answer 20

pyrexia
tachyapnoea
tachycardia
confusion
Kussmauls breathing

Question 21

Which appearance of an affected digit is diagnostic of osteomyelitis?

Answer 21

swollen affected digit - sausage-like

Question 22

Why would a swollen forefoot feel ‘boggy’?

Answer 22

due to the abscess underneath

Question 23

What is crepitus and where would you find it?

Answer 23

gas in soft tissues of foot - gas released from forming organisms

Question 24

Where would you feel for the dorsals pedis pulse?

Answer 24

anterior surface of foot, between 1st and 2nd metatarsal bones;
lateral to the extensor hallucis longus

Question 25

Where would you feel for the popliteal artery?

Answer 25

deep within the popliteal fossa - compress against posterior of distal femur with knee slightly flexed

Question 26

Where would you feel for the femoral artery?

Answer 26

patient lying flat - place finger directly above pubic ramas, halfway between the pubic tubercle and the anterior superior iliac spine (ASIS)

Question 27

Broad or narrow spectrum antibiotics for diabetic foot sepsis? Why?

Answer 27

broad spectrum - to cover for the poly-microbial nature of the infection