226 - Varicose Veins Flashcards
What is a varicose vein?
Enlarged and twisted vein
Which veins are varicose veins most common in?
90% Long saphenous vein (medial side)
Rest usually short saphenous vein
What symptoms can you get with Varicose veins?
Mostly cosmetic
painful, achy, heavy when standing for long periods
Restless leg syndrome
What complications can varicose veins cause? (7 things)
Chronic venous insufficiency -> oedema Thrombophlebitis Hamorsiderin staining Varicose eczema leg ulcers Haemorrhage Lipodermatosclerosis
What is lipodermatosclerosis?
Skin hardness due to s/c fibrosis, inflammation and necrosis of s/c adipose tissue
- pain, brownish-red staining
- inverted champagne bottle leg
What causes varicose veins?
Primary cause unknown
? age (veins loose elasticity)
? imobility / standing (no muscle pump)
? female - progesterone effect on vessel walls
Secondary - impaired flow from deep system
- DVT
- Abdominal mass
Describe the process of varicose vein formation
Valvular incompetance, reflux, hypertension -> stress distally
or, cellular and ECM changes -> vein wall weakens - venous dilatation - valvular incompetance
What are the 5 key treatment options for varicose veins?
Surgery - strip vein Radiofrequency ablation EVLT - Endovenous laser treatment Foam sclerotherapy Compression therapy
What can be done if there are leg ulcers caused by arterial ischaemia?
Bypass surgery of artery
What is chronic oedema?
Oedema lasting more than 3 months
What are the 4 key types of chronic oedema?
Lymphovenous
Dependancy
Lipoedema
Lymphodema
Describe lymphovenous oedema
A lymphatic overload
Venous system pathology causing increased capilary filtration
s/c tissues are soft and pitting
oedema reduces with elevation
What tissue changes can be seen in lymphovenous oedema?
Haemosiderin staining Ulceration varicose eczema Lipodermatosclerosis Telangicetasia
What is dependancy oedema?
A lymphatic overload Gravitational Occurs in dependant, immobile limbs reduced venous return -> increased cap filtration Often people with comorbidities
What tissue changes are seen in dependancy oedema?
Translucent skin
Wet legs - lymph leaks
Shiny
soft + pitting
What is lipodema?
A lymphatic overload Symmetrical fatty deposits occur ? disterbed venous function ? normal lymph system But lymph transport capacity is reduced - > backlog
What is lymphoedema?
Oedema with a normal lymph load
There is normal capillary filtration but reduced lymphatic drainage - so increased protein conc
What are the primary causes of lymphoedema?
Congenital - aplasia, hypoplasia, valvular incompetance
Herediatory - milroy’s
What are the secondary causes of lymphoedema?
Parasitic - filleriasis (blocks lymph ducts) Obstruction of vessels Trauma Cancer - lymph clearance Infection Venous disease Immobility
What signs are seen in lymphoedema?
Tickened, non-pitting s/c tissue Dry and flaky skin Doesn't reduce with elevation Limb misshapen Aching and heaviness Altered sensation on skin
What are the management approaches for lymphoedema?
Skin care
Multi-layer bandaging
Exercises
Weight management
When is lymphatic damage suspected in an oedematous limb?
When the swelling doesn’t resolve overnight or with elevation
Which vessels make up the microcirculation of the body?
Arterioles, capillaries, vennules
What are the functions of the microvessels?
Transport, convection, diffusion
Who first produced the evidence that microvessels existed?
Harvery - discovered circulation
Malpighi - Saw microvressels first in frog lung capillaries
What species/part was studied to discover the organisation of microvessels?
Rat cremaster muscles
What is vasomotion of microvessels?
The intermittancy of flow.
Terminal arterioles open and close
Allows for fluid reabsorption
What are the 3 structural types of capillaries and where are they found?
Continuous - flattened, wrap around junction, in skin, lung, muscle.
Fenestrated - have windows in cells to increase filtration - choroid plexus, GI mucosa, glands
Discontinuous - gaps (100nm) between cells - BM, spleen, liver
What is the diffusional permeability relationship?
Js = -PS x Conc change A variation of flicks law P=permeability depends on what substance is crossing s= surface area Js = diffusion rate
What are the differences in permeability of lipid soluble, water soluble and larger solutes, and what does this mean?
Lipid soluble (eg. O2) - high perm - as expected as lipid bilayer
Water soluble (glucose, hormones) - high perm - higher than expected if just a lipid bilayer - there must be water filled channels - Small pore system?
Larger solutes - reduced permeability - different sizes have different permeabilities - molecular sieving with limit of about 5nm. But some larger ones do get through - large pores too?
Describe the mechanisms that enable different solutes to diffuse across a capillary wall
Lipophilic - transcellular diffusion
Water soluble - Intracellular small pores + fenestrations
LArge solutes - Endothelial gaps of inflammation, transendothelial channels (large pores), vesicular transport
What is the glycocalx in a capillary?
How sieving works?
A carbohydrate polymer that excludes larger proteins - so they can’t get close to the capillary wall to try get across.
How do we explain small pores existing in capillary walls?
Clefts between cells
Despite tight junctions occuring between cells, there are small clefts between that could form channels.
They are slightly too big so the glycocalx acts as a sieve
How does fluid cross vessel walls?
By convection across microvessel walls
What principle is applied to fluid movement across vessel walls?
Starlings principles
Tissue fluid balance - most well perfused capillaries filter fluid along their length
How much fluid is taken up by the lymphatic system a day?
8L / day
What are the 2 mechanisms that cause oedema?
Reduced lymphatic drainage
Increased cap filtration rate
What 3 mechanisms can increase cap filtration rate?
Increased capillary pressure (heart failure in lungs)
Reduced oncotic pressure (plasma proteins lost through kidneys - kidney or liver diesase)
Increased hydrolic permeability (inflammation - larger gaps)
What pressure changes are seen int he leg veins when we stand up?
Pressure increases from 10 mmHg to 90 mmHg
When muscle pumps are working when standing what pressure is in the leg veins?
10 mmHg
If the leg veins have incompetent valves, what is the pressure in them on standing even with muscle pump action
60 mmHg
