Acute Limb Threat Flashcards
Define acute limb ischaemia.
sudden loss of blood supply to a limb - occlusion of native artery or bypass graft
What is the essential thing to distinguish between in acute limb ischaemia?
acute ischaemia vs acute on chronic ischaemia
Name some causes of sudden occlusion?
embolism, athero-embolism, arterial dissection, trauma, extrinsic compression
What are the clinical features of acute limb ischaemia? (6 Ps)
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
What needs to be checked when talking a history/examination of acute limb ischaemia?
No prior history of claudication
Known cause for embolism (mostly cardiac)
Full complement of contra-lateral pulses
What does a ‘woody’ compartment indicate in a calf/muscle?
muscle necrosis
What does blanching mottling indicated in a limb?
capillaries have refilled with stagnated deoxygenated blood -> mottled appearance (purple-ish)
= ischaemia is partially reversible
What does a non-blanching limb indicate?
irreversible ischaemia
arteries distal to occlusion have filled with propagated thrombus with rupture of capillaries
Is a limb salvageable once paraesthesia/paralysis sets in?
only if prompt re-vascularisation
What happens if you transfuse a patient blood if they have had acute limb ischaemia >12hrs?
kills the patient since perfusion attempt has circulated all the bad stuff from the dead tissue
How would you manage an acute limb ischaemia?
ABC resuscitation and investigation.
FBC, U&E, CK, Coag ± troponin
Anti-coagulate
Why could an underlying malignancy be the cause of acute limb ischaemia?
(adenocarcinoma) patient will be pro-thrombotic
Which tests would you do in management of acute limb ischaemia?
ECG - MI, dysarrhythmia
CXR - underlying malignancy
Arterial imaging (only if not certain it is due to an embolus) - CT/catheter angiogram
What are the methods of clearing/dissolving a clot?
Embolectomy - clearing out clot
Fasciotomy - to avoid compartment syndrome
Thrombolysis
What is the triad of diabetic foot sepsis?
tissue ulceration
necrosis
gangrene
Where do neuro-ischaemic ulcers occur?
areas of raised pressure i.e. under metatarsal heads
Where might the source of sepsis be in diabetic foot sepsis?
simple puncture wound
infection from nail plate/inter-digital space
from a neuro-ischaemic ulcer
Why is infection a big problem if in the foot?
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
What are the foot compartments bound by?
plantar fascia
metatarsal bones
interosseous fascia
What would be the clinical findings in diabetic foot sepsis?
pyrexia tachyapnoea tachycardia confusion Kussmauls breathing
Which appearance of an affected digit is diagnostic of osteomyelitis?
swollen affected digit - sausage-like
Why would a swollen forefoot feel ‘boggy’?
due to the abscess underneath
What is crepitus and where would you find it?
gas in soft tissues of foot - gas released from forming organisms
Where would you feel for the dorsals pedis pulse?
anterior surface of foot, between 1st and 2nd metatarsal bones;
lateral to the extensor hallucis longus
Where would you feel for the popliteal artery?
deep within the popliteal fossa - compress against posterior of distal femur with knee slightly flexed
Where would you feel for the femoral artery?
patient lying flat - place finger directly above pubic ramas, halfway between the pubic tubercle and the anterior superior iliac spine (ASIS)
Broad or narrow spectrum antibiotics for diabetic foot sepsis? Why?
broad spectrum - to cover for the poly-microbial nature of the infection
