L20 - Peripheral arterial and venous disease

Question 1

Explain the venous system drainage in the lower limb

Answer 1

Two systems - deep (major arteries) and superficial veins. Blood drains from superficial to deep via perforating veins then on to RA

More in depth - long and short saphenous veins drain from dorsal venous arch, long drains anteriorly (to medial malleolus) and empties to femoral, short drains posteriorly (posterior to lateral malleolus) and drains into popliteal. Fermoral drains to external iliac -> common iliac -> inferior vena cava
Also on plantar foot, medial and lateral plantar veins unite to form posterior tibial and peroneal which then enter into popliteal

Question 2

Explain why the calf muscles are sometimes called ‘the peripheral heart’

Answer 2

Because contraction of the soleus and gastrocnemius muscles close the valves in perforating veins preventing retrograde movement of blood flow and allow opening in front to push it into the deep veins and towards the heart

Question 3

Explain varicose veins in peripheral venous disease

Answer 3

Normally the result of ‘varicose veins’ (severely dilated), the valves in the veins become ineffective and blood movement is slowed or even reversed. Walls of the vein become weak

Question 4

Although peripheral venous disease doen’t normally cause any severe problems, describe some possible symptoms of someone with it

Answer 4

Pain ALONG THE AFFECTED VEIN/skin pigmentation/oedema around the affected area/venous eczema and ulceration (this is due to venous hypertension)

Question 5

Who is most at risk of peripheral venous disease and why?

Answer 5

People who are immobile for periods of time - long term injury.obese etc. because plantar flexion of the ankle is required to keep the calf muscle pump effectively contracting the veins

Question 6

What is the treatment for peripheral venous disease

Answer 6

vein stripping and ligation (of superficial veins)/injection of a sclerosing agent to close off the vein

NOTE - the long saphenous veins is commonly harvested for coronary artery bypasses

Question 7

Venous and arterial thrombosis (blood clot formation) are precipitated by different pathophysiology. Arterial thrombosis comes about because of atherosclerosis. How does venous thrombosis come about?

Answer 7

Stasis of blood often combined with another factor e.g. inflammation (hypercoagulability)/dehydration/chemotherapy/trauma

Question 8

What is Virchow’s triad?

Answer 8

Describes the three major factors contributing to thrombosis - stasis/vessel wall damage/hypercoagulability

Question 9

What is a deep vein thrombosis?

Answer 9

Clotting of blood in a deep vein - most commonly in the calf

Question 10

Describe some patients who are at particular risk of DVT

Answer 10

Immobile patients - post surgery(hypercoagulable state)/post flight/disabled

Question 11

What are the signs and symptoms of a DVT?

Answer 11

Warm, distended veins at site/calf tenderness/oedema at site/pyrexia with no other obvious cause

Question 12

What are some differential diagnosis’ of a patient you may think has a DVT?

Answer 12

lymphatic blockage/cellulitis/soft tissue trauma

Question 13

What is the treatment for a DVT and what is the biggest complication it can cause?

Answer 13

Anticoagulatns and possibly surgery/PE

Question 14

What is the physiological adaptation that we have at our joints that prevents ischaemia when we flex them and thus occlude the major blood vessels?

Answer 14

collateral circulation (vessels)

Question 15

Peripheral arterial disease can cause acute limb ischaemia. This is bad because if the ischaemia comes on quickly then no collaterals have formed and infarction can occur. What are the 6P’s which describe the signs and symptoms of acute limb ischaemia

Answer 15

Pain
Pallor 
Perishing with cold
Pulseless
Paraesthesia 
Paralysis

Question 16

Acute limb ischaemia can sometimes be resolved with angioplasty (stenting)/thrombectomy/thrombolytics etc. but sometimes needs amputation, why is this?

Answer 16

So the necrosis and hyperkalaemia doesn’t spread elsewhere

Question 17

What are some signs of chronic peripheral arterial disease?

Answer 17

Intermittent claudication/ more severe if cramping is on rest/ulceration and gangrene/patient may describe hanging their leg out of bed eases the pain/lack of certain pulses

`NOTE - ulceration is a breach of skin/membrane caused by necrotic tissue coming out

Question 18

What are the four lower limb pulses, describe exactly where they are found

Answer 18

Femoral pulse - mid inguinal point (halfway between ASIS and pubi symphysis)
Popliteal pulse - deep in popliteal fossa
Dorsalis pedis pulse - Just lateral to extensor hallicus longus tendon on dorsum of foot
Poterior tibial pulse - Just posterior to the medial malleolus

Question 19

Doppler ultrasound is used to measure velocity and direction of blood flow in peripheral arterial and venous disease. Explain the basics

Answer 19

Ultrasound produced from transducer and positioned over lumen of artery, ultrasound will be bounced back and can work out direction and velocity based on how it returns to the transducer

Question 20

Describe the arterial supply of the lower limb

Answer 20

dorsum - dorsalis pedis artert -) anterior tibial artery -> popliteal artery -> femoral artery -> external iliac artery -> common iliac artery -> abdominal aorta

Posterior tibial artery runs up posterior leg and joins anterior tibial to form popliteal artery