Session 11.1 Flashcards
(29 cards)
How does blood flow through the venous system?
From superficial veins through perforating veins into deep veins
NB: the calf muscle pump contraction generates pressure to push blood in the deep vein back to the heart
What are the deep veins of the leg??
- external Iliac vein
- Femoral vein
- popliteal vein
- calf veins
What are the superficial veins of the leg?
- the long saphenous vein (tributaries in front of the medial malleolus)
- the short saphenous vein (lateral side of calf down past the lateral malleolus)
Where does the short saphenous vein rejoin the deep veins?
At the popliteal vein
Where does the long saphenous vein join the deep veins?
The femoral vein
What are varicose veins and whats the pathophysiology?
Varicose veins are tortuous, twisted or lengthened veins
The vein wall is inherently weak in these veins, which leads to dilation and separation of valve cusps so they become incompetent.
NB: The aren’t dangerous in themselves
What are the symptoms of varicose veins?
Symptoms must be along the vein itself
- heaviness
- tension
- aching
- itching
What are the complications of varicose veins?
From the vein itself
- haemorrhage
- thrombophlebitis (inflammation of vein due to thrombosis) occurs due to low blood velocity. Produces an inflammatory response, including pain. You can see the outline of the vein.
From venous hypertension
- oedema
- skin pigmentation e.g haemosiderin staining as red cells leak out, macrophages ingest RBC, iron in blood is oxidised from ferrous to ferric = can see rust under skin.
- varicose eczema
- lipodermatosclerosis - skin is hard and yellow bits on surface.
- venous ulceration. Smelly, difficult to heal and painful.
Why would varicose veins bleed in the shower?
Standing up = pressure is increased in veins and warm showers = vasodilation.
Lie patient down and elevate legs above heart = bleeding will stop
How do you get venous hypertension?
As a result of calf muscle pump failure
Why do you get calf muscle pump failure?
- deep vein incompetence
- failure of calf muscle contraction: immobility, obesity, reduced hip, knee and/or ankle movement
- volume overload
What’s a retrograde circuit in the calf muscle pump?
Go through valve the wrong way instead of flowing normal from superficial to deep
Calf muscle pump becomes over full with blood
What’s Virchow’s triad?
Helps explain the pathophysiology of thrombosis Is - changes in lining of vessel wall - changes in flow of blood - changes in constituents of blood
How do you get arterial thrombosis?
From virchows triad
- changes in the lining of the vessel wall
E.g due to atheroma
How do you get venous thrombosis?
From virchows triad
- changes in flow of blood
Stasis leads to venous thrombosis
Why does stasis lead to venous thrombosis?
Usually stasis and another factor e.g surgery, the pill, dehydration and cancer etc.
What is the constitution of an arterial thrombosis in response to bleeding?
Involves platelets so are platelet rich
What’s the difference between venous bleeding and arterial bleeding?
Venous
- dark, oozing.
- involves intrinsic pathways. Overcome with anti- coagulant agent.
Arterial
- spurting.
- platelets then intrinsic and extrinsic pathways.
- aspirins work against platelets so use if you want to stop arterial thrombosis.
What do venous thrombi mainly consist of and what does this lead to?
Fibrin, formed from fibrinogen
Produces an inflammatory response (rubor, tumor, dolor, calor, reduced function).
What are the signs and symptoms of a DVT?
Symptoms
- pain, cannot walk
- swelling
- blue - red skin discolouration
Signs
- calf tenderness
- muscle induration
- skin warmth
- skin discolouration
- distended, warm, superficial veins
- oedema
- pyrexia
How is DVT linked to surgery??
- immobility prior to surgery
- no calf muscle pump during surgery
- immobility after surgery
- surgery is trauma
Dvt can lead to pulmonary embolism
What’s a collateral circulation?
The alternate circulation around a blocked artery or vein via another path, such as nearby minor vessels.
Development takes weeks or months. Provided you’ve got stenosis beforehand, can form pathologically.
Common around joints e.g elbow and joints.
What’s acute limb ischaemia?
Poor blood supply to limb occurs quickly so no time for collateral circulation to form.
Commonest cause - embolism (from heart or abdominal aortic aneurysm) and trauma.
Sudden onset.
If not reversed within 6 hours cannot be recovered and if not amputated the patient will die (hyperkalaemia due to dead tissue releasing intracellular potassium).
What Are the symptoms of acute ischaemia?
The 6 P’s
- pain
- paralysis
- paraesthesia (pins and needles)
- pallor
- perishing cold
- pulseless
Limb goes pale to being synoptic, then goes blue due to reduced haemoglobin then go red after 6 hours.
