Vascular 3 Flashcards
What is the thoracic outlet?
Space between the first rib and clavicle, through which the subclavian artery, subclavian vein and brachial plexus pass
What is thoracic outlet syndrome?
Narrowing of the thoracic outlet causing neurological or arterial symptoms
What are the causes of thoracic outlet syndrome?
Cervical rib
Healed clavicular fracture
Excess muscle development
What is the presentation of thoracic outlet syndrome?
Neurological deficits in the T1 distribution - wasting of teh small muscles of the hand, paraesthesia of the inner forearm and hand
Arterial symptoms - upper limb claudication: if working with hands above head
post-stenotic dilatation (aneurysm) which can thrombus to cause acute arterial occlusion
What examinations / investigation findings of thoracic outlet syndrome are there?
Arm BP will be lower in the affected arm and vary with posture
Arteriography can confirm obstruction, and plain XR will show a cervical rib or healed clavicular fracture
What is the management of thoracic outlet syndrome?
often surgical, with excision of the cervical rib and often the first rib with any obstructing fibrous bands
Post-stenotic subclavian aneurysm will also need grafting
How many venous systems are there in the lower limb?
2: superficial and deep venous system
What is the deep system made of? what does it do?
A number of veins that accompany the major arteries of the lower limb and drain the muscular compartment
What is the superficial system made of?
Superficial: medial long (great) saphenous vein which drains to the saphenofemoral junction and the laterally placed short saphenous vein which drains into the popliteal vein
What is the function of the superficial system?
Drains the skin and superficial tissues
Where are the two systems joined?
at the saphenofemoral and saphenopopilteal junctions
What are the perforating veins?
Additional communications between the two systems
What is the function of valves in the leg veins?
Prevent backflow of blood
Are there valves in the vena cava / common iliac veins?
What is the effect of this?
Central pool of blood in the trunk
What is venous return to the heart driven by?
Pressure from the muscular pumps below, and inspiration decreasing intrathoracic pressure
As the calf muscles contract, the deep veins are squeezed and emptied, to force blood upwards
As the muscle relaxes, blood from the superficial system will flow into the deep veins via the perforators, which will again be squeezed upwards as the calf muscles contract once more
What does venous disease in the deep veins lead to?
Deep venous insufficiency
What does venous disease in the superficial veins lead to?
Simple varicose veins
What is the cause of venous disease in either the superficial / deep venous system?
Valvular incompetence
What are varicose veins?
dilated, tortuous, superficial veins that occur secondary to incompetent venous valves, allowing blood to flow back, away from the heart. They most commonly occur in the legs due to reflux in the great saphenous vein and small saphenous vein
Which is more common, primary or secondary varicose veins?
Who gets them?
Primary
twice as common in women, with pregnancy accentuating symptoms
Likely to be due to a primary superficial valve defect, with familial elements
(no deep venous incompetence)
What is the cause of secondary varicose veins?
Superficial varicosities occurring secondary to deep venous incompetence:
Previous DVT: although occluded veins recanalise, their valves remain incompetent
Raised systemic venous pressure: due to compression (pelvic tumour, pregnancy), artery-venous fistula or severe tricuspid incompetence
What are the symptoms of varicose veins?
Cosmetic
tiredness, aching or throbbing of the legs
Oedema of the ankles, particularly on standing for long periods
Itching and nocturnal cramps are reported
signs of deep venous insufficiency: haemosiderosis, eczema, lipodermatosclerosis
When does deep venous insufficiency occur?
When the valves of the deep venous system are incompetent
Calf can no longer efficiently return blood to the thoracic cavity
can be primary or secondary
What is the primary cause of deep venous insufficiency?
Secondary?
primary: congenital absence of the valves
Secondary: DVT causing valvular damage or AVF raising venous pressure
What are the features of deep venous insufficiency?
Lower limb aching pain/discomfort
oedema of the lower leg
superficial varicose veins - raised central pressure causes perforator incompetence
Haemosiderin deposition in the gaiter area
eczema - particularly over the pigmented area, causing pruritus
Atrophie blanche
Lipodermatosclerosis: subcutaneous fissure replaced by thick fibrous tissue, giving an inverted champagne bottle appearance
Ulceration
How is deep venous insufficiency confirmed?
Duplex sonography or venography to confirm diagnosis of deep venous insufficiency