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Venous insufficiency is a chronic condition in which the leg veins do not send blood
back to the heart in an efficient manner. This condition is caused by weakness of
the valves in the superficial and/or deep veins of the leg. The superficial veins
are located under the skin and are visible in many people. The deep veins are located
deep within the muscles of the leg and are not visible through the skin. When the
valves in either the superficial or deep veins become "leaky", the pressure rises
in the veins which causes them to dilate. When the superficial veins elongate, they
become winding and "tortuous" rather than straight. At this point they are called
"varicose veins". The deep veins are supported by the leg muscles so they do not
stretch out as much and do not become "varicose". The mechanism for the development
of varicose veins and for the development of chronic venous insufficiency of the
deep system is similar. In both cases, the valves in the veins are damaged and are
no longer effective in preventing reflux of blood down the legs rather than propelling
the blood out of the legs toward the heart. Chronic venous insufficiency of the
superficial veins can be caused by damage to the valves in the superficial veins
of the leg as a result of trauma to the superficial veins, hereditary factors, occupations
involving prolonged standing, or an episode of superficial phlebitis. Since the
superficial veins are not needed for the normal function of the leg and are "extra
veins" (these are the veins that surgeons take from the leg to create a heart bypass,
for example) when they become insufficient and "varicose" and cause pain, skin discoloration,
unacceptable appearance or leg swelling, the treatment is to either remove the veins
surgically or use the laser to permanently seal up the veins and eliminate blood
flow through them.
Chronic venous insufficiency of the deep veins is usually caused by damage to the
valves following an episode of deep vein thrombosis (DVT). It is manifested as aching,
heaviness, or cramping in the legs. Other symptoms include itching of the skin,
pain in the legs that is worse with standing and improved by lying down, and swelling
of the legs. When the swelling and pain is extremely debilitating after an episode
of DVT, this condition is sometimes referred to as the "post-phlebitic syndrome".
With time, high pressure in the leg veins due to venous insufficiency of either
the superficial or deep veins (or both) can cause leakage of blood out of the capillary
beds and accumulation of hemoglobin pigment in the skin itself. This causes a brown
discoloration of the skin of the lower legs. This condition is called “venous stasis
pigmentation”. Inflammation of the skin of the lower leg can be the next stage in
this progressive condition. This condition is called “venous stasis dermatitis.”
With longstanding dermatitis and stasis pigmentation, the skin of the lower legs
can become thick, dry, and fragile. This may lead to ulceration of the skin ("venous
stasis ulceration") - usually on the inside aspect of the leg just above the ankle.
The treatment of chronic venous insufficiency is to support the veins externally
by wearing compression stockings. Elevation of the leg when there is swelling and
pain is also useful. The skin of the leg needs to be kept moisturized with lotions
to avoid dry skin which is more easily damaged by even minor trauma. Avoidance of
long periods of standing is also recommended. While varicose vein surgery (or laser
treatment) is extremely effective in relieving symptoms and improving the appearance
of patients who have venous valvular insufficiency of the superficial veins, this
treatment cannot be used for the deep veins of the legs. There is currently no consistently
effective surgical therapy for chronic venous insufficiency of the deep system.
Operative approaches including valve repairs, valve transplantation, and other techniques
have been tried to treat venous insufficiency of the deep vein system but the results
have been inconsistent and disappointing.
In answer to the question of why don't giraffes get varicose veins and have chronic
venous insufficiency despite their great height and the very elevated pressures
in the veins of their legs? Two reasons: (1) Giraffes do not have superficial veins
in their legs and (2) The deep veins within their leg muscles are supported by a
thick, tough, connective tissue which prevents the veins from stretching out due
to high pressure and also prevents leg swelling and leakage of blood and fluids
from the veins. It is as if they are constantly wearing very tight support stockings!