226 - Varicose Veins

Question 1

What causes peripheral vascular disease?

Answer 1

atherosclerotic stenosis/occlusion of large/medium arteries. BP at ankle should be higher than in arm but lower in disease. blood flow cant increase on exertion causing claudication. In later stages resting blood flow reduce and ischaemia causes ulcers. lIvedo reticulares purple discolouration due to stagnation of blood
*risks - smoking, diabetes, HTN, hyperlipidaemia, FH, sedentary lifestyle

Question 2

what are the differences between arterial and venous ulcers?

Answer 2

arterial over bony prominances venous gaiter region
art smaller, more painful and demarcated
art punched out ven superficial
art necrotic centre, ven granulating centre
ven exuadative and hyperpigmented which art blanched

Question 3

what are the 5ps of peripheral vascular disease?

Answer 3

• pulselessness
• paralysis
• paraesthesia
• pain
• pallor

Question 4

how is the ankle-brachial pressure index measured (ABPI)?

Answer 4

ratio of ankle BP to brachial BP. normal >1 mild 0.9-0.7 mod 0.7-0.5 and severe rest pain

Question 5

what would be expected in a patient with peripheral vascular disease on doppler pulse studies?

Answer 5

• Monophasic waveform

* normal is triphasic waveform

Question 6

what treatment is available for AVD?

Answer 6

• lifestyle change
• antiplatelets, statins
• surgical - balloon dilatation, stenting, bypass

Question 7

what causes venous hypertension?

Answer 7

*valvular incompetence - reflux occurs leading to a column of uninterupted blood forming in veins and incr. venous pressure

Question 8

what are signs of venous HTN?

Answer 8

• varicose veins - dilated torturous superficial veins with dull ache on standing still/sitting made better by elevation
• Lipodermatosclerosis - scarring of skin and fat with brown smooth tightened skin and pain
• venous eczema (stasis dermatitis) - fibrin activation on skin, ischaemia and immune cells causing inflammation and fibrosis due to chronic venous oedema. Erythema and hyperpigmentation and scaling

Question 9

what tests are there for venous HTN?

Answer 9

• Trendelenburg test - leg elevated to empty superficial veins, sapheno-femoral junction occluded, pt stands _slowfilling= problem at SF junction, fast filling=incompetent perforators
• venous refill time - calf muscle pump used to empty veins, pt stands ,time for varocosities to refill

Question 10

what treatment options are available for venous HTN?

Answer 10

• graduated compression bandaging - PVD must be excluded first
• surgery -saphenectomy
• stab phelebectomy
• endovenous ablation
• sclerotherapy (foram - STD)
• endovenous laser treatment

Question 11

what are the different types of chronic lymphoedema?

Answer 11

• lymphoedema - inadequate drainage, normal cap filtration, incr. protein conc.
• lymphovenous oedema - venous system pathology, incr. cap filtration
• dependency oedema - immobile limbs, decr. venous return, inc cap filtration

Question 12

what are the 2 pathways for microcirculation?

Answer 12

• terminal arteriole>capillary>post capillary venule

* arteriole>AV anastamosis>larger venules

Question 13

what do terminal arteries do?

Answer 13

supply bunch of cap and carry out vasomotion to produce intermittent flow of blood

Question 14

what happens to post capillary venules in inflammation?

Answer 14

become incr permeable causing leakage of plasma into interstitium and swelling/heat

Question 15

what do arterio-venous anastomoses do?

Answer 15

only in some cap beds in skin extremities. open at high body temps>lower resistance and incr blood flow to skin and heat loss

Question 16

how does diffusional permeability vary along a capillary?

Answer 16

more permeable at venous end of cap and more reabsorption.

Question 17

what is the diffusion rate in a capillary dependent on?

Answer 17

Js=-Ps(conc. diff)

• permeability of cap wall
• surface area of cap wall
• conc gradient across wall

Question 18

how do lipid soluble molecules and hydrophilic molecules pass through capillary walls?

Answer 18

• highly permeable to lipid soluble molecules and anaesthetics - transcellular and diffusion through extracellur pathways
• less permeable to hydrophilic molecules as must diffuse through pores and permeability depends on molecule size

Question 19

what are the 3 types of capillaries?

Answer 19

• continous capillaries - skin, lungs, connective tissue, muscle, CNS - single layer of epithelial cells with small pores in intracellular clefts - discontinuous tight junctions
• fenestrated capillaries - areas of high fluid filtration out of caps eg kidneys, glands, intestinal mucosa - endothelium with pores and basement membrane highly permeable
• sinusoids - areas of high cellular exchange - eg spleen, liver, bone marrow - endothelium with large gaps and discontinuous basement membrane

Question 20

what carries out molecular sifting in extracellular pathways?

Answer 20

glycocalyx - layer of -ve charged carbohydrate covering endothelium that binds plasma proteins to form an exclusion zone and makes pores smaller

Question 21

what prevents the accumulation of fluid in the interstitium?

Answer 21

• vasomotion - intermittent flow reduces ave pressure in cap and incr absorption
• lymphatic drainage - large junctions so easy movement of fluid. Muscle contraction and valves push fluid through. relaxation allows less P and more fluid sucked in

Question 22

what causes excess fluid in interstitial space (oedema)?

Answer 22

cap filtration rate > lymphatic drainage rate
cap filtration rate=LpS[(Pc-Pi) - sigma(PIpl - PIi)]
*incr in cap filtration rate due to high hydrostatic P in capillaries (heart failure) and low plasma oncotic P due to decr. plasma protein conc (malabsorption, malnutrition, liver failure)
*decr in lymphatic drainage due to cancer damage in lymph nodes, surgical damage, filariasis (roundworm infect lymphatics)

Question 23

what are venous BP in the feet standing and lying down>

Answer 23

lying 10 mmHg standing 90mmHg