peripheral vascular system Flashcards
how is lower limb ischaemia defined
ABPI <0.9 at rest
classification of lower limb ischaemia
I asymptomatic
II intermittent claudication
III night/rest pain
IV tissue loss
what is intermittent claudication
pain felt in the legs on walking due to arterial insufficiency
what is the claudication distance
how far patients say they can walk before the pain stops them from walking
what is neurogenic claudication
due to neurological and musculoskeletal disorders of the lumbar spine
what is venous claudication
due to venous outflow obstruction from the leg, following extensive DVT.
relieved by leg elevation
why do patients get night/rest pain and what does it indicate?
poor perfusion resulting from the loss of the beneficial effects of gravity on lying down and the reduction in HR, BP and CO that occurs when sleeping.
indicates severe, multilevel lower limb PAD and is a red flag symptom as failure to revascularise the leg usually leads to the development of critical limb ischaemia with tissue loss (gangrene, ulceration) and amputation
how can you differentiate between diabetic neuropathy and rest pain?
neuropathic pain is not usually confined to the foot and is associated with burning and tingling and is associated with dysaesthesia
why do patients with severe lower limb PAD get gangrene and/or ulceration
even trivial injuries to the feet fail to heal allowing bacteria to enter.
signs of lower limb PAD
- ischaemic signs: absence of hair, thin skin and brittle nails
- diminished/absent pulses
signs of acute limb ischaemia
- pulseless
- pallor
- perishingly cold
- parasthesiae
- paralysis
- pain on squeezing muscle
in acute limb ischaemia, what is the difference in onset and severity between embolus and thrombosis?
embolus: acute, ischaemia profound, no co-existing collaterals
thrombosis: insidious (hours or days), ischaemia less severe (pre-existing collaterals)
commonest causes of acute limb ischaemia
- thromboembolism: usually from the left atrium in association with AF
- thrombosis in situ: thrombotic occlusion of an already narrowed atherosclerotic arterial segment
What happens a few hours after an acute arterial occlusion?
the spasm relaxes and the skin microcirculation fills with deoxygenate blood, leading to light blue or purple mottling, which has a fine reticular pattern and blanches on pressure
what happens in compartment syndrome?
occurs where there is increased pressure within the fascial compartments of the limb, most commonly the calf, which compromises perfusion and viability of muscles and nerves.
Are ischaemic strokes or haemorrhagic strokes more common?
ischaemic
What do strokes in the vertebrobasilar artery territory causes?
giddiness, collapse with or without loss of consciousness, transient occipital blinds or complete loss of vision in both eyes
what do strokes in the carotid artery territory cause?
vary according to the cerebral area but can include motor deficit, visual field defect or difficulty with speech
what are symptoms and signs of chronic mesenteric arterial insufficiency?
- severe central abdo pain developing after 10-15 mins after eating
- weight loss (pt scared of eating)
- diarrhoea
- profound metabolic acidosis
main risk factors for an AAA
smoking
hypertension
familial/genetic element
three times more common in men
the most common misdiagnosis for a ruptured AAA?
renal colic
what is raynauds phenomenon?
Digital ischaemia induced by cold and emotion and has three phases
- pallor (spasm)
- cyanosis (deoxygenation of static venous blood)
- redness (reactive hyperaemia)
what should you always ask about in men with buttock (gluteal) intermittent claudication?
may have erectile dysfunction
what does purple discolouration of the fingertips indicate?
atheroembolism from a proximal subclavian aneurysm
what does wasting of the small muscles of the hand indicate?
thoracic outlet syndrome
what does corneal arcus and xanthelasma indicate?
hypercholesterolaemia
what does Horners syndrome indicate
carotid artery dissection or aneurysm
what does hoarseness of the voice and bovine cough indicate
recurrent laryngeal nerve palsy from a thoracic aortic aneurysm
how do you perform Buerger’s test
- raise patients feet and legs to 45 degrees
- watch for pallow
- ask the patient to sit up and hang the legs over th
bed - watch for reactive hyperaemia
what is the ABPI?
ratio of the highest pedal artery to the highest brachial artery pressure
if the popliteal artery is easy to feel, what might you suspect?
an aneurysm
ABPI in intermittent claudication and critical limb ischaemia?
<0.9 and <0.4 respectively
what are the 4 ways that lower limb venous disease presents?
- varicose veins
- superficial thrombophlebitis
- DVT
- chronic venous insufficiency and ulceration
what are varicose veins?
dilated, tortuous superficial veins causing aching, itching and swelling
what does DVT cause?
-pain and tenderness in the affected part (calf)
what does superficial thrombophlebitis cause?
red, painful area overlying the vein involved
what is lipodermatosclerosis associated with?
chronic venous insufficiency.
causes of leg ulcers?
probably venous disease
syphilis
Tb
sickle cell
why do non-occlusive DVTs pose the greatest threat of PE?
clot lies within a flowing stream of venous blood and is more likely to propagate and has not yet induced an inflammatory response in the vein wall to anchor it in place
what can oedema and a raised JVP suggest?
cardiac disease or pulmonary hypertension
