Atlas of pathophysiology, 2 Edition

Part II - Disorders

Cardiovascular disorders

Varicose Veins

Varicose veins are dilated, tortuous veins, engorged with blood and resulting from poor venous valve function. They can be primary, originating in the superficial veins, or secondary, occurring in the deep veins.

Causes

Primary varicose veins

·   Congenital weakness of valves or vein wall

·   Prolonged venous stasis or increased intra-abdominal pressure, as in pregnancy, obesity, constipation, or wearing tight clothes

·   Standing for an extended period of time

·   Family history

Secondary varicose veins

·   Deep vein thrombosis

·   Venous malformation

·   Arteriovenous fistulas

·   Venous trauma

·   Occlusion

Pathophysiology

Veins are thin-walled, distensible vessels with valves that keep blood flowing in one direction. Any condition that weakens, destroys, or distends these valves allows the backflow of blood to the previous valve. If a valve can't hold the pooling blood, it can become incompetent, allowing even more blood to flow backward. The increasing volume of blood in the vein raises pressure and distends the vein. As the veins are stretched, their walls weaken and lose their elasticity, and they become lumpy and tortuous. Rising hydrostatic pressure forces plasma into the surrounding tissues, resulting in edema.

People who stand for prolonged periods may also develop venous pooling because there's no muscular contraction in the legs, forcing blood back up to the heart. If the valves in the veins are too weak to hold the pooling blood, they begin to leak, allowing blood to flow backward.

Signs and symptoms

·   Dilated, tortuous, purplish, ropelike veins, particularly in the calves

·   Edema of the calves and ankles

·   Leg heaviness that worsens in the evening and in warm weather

·   Dull aching in the legs after prolonged standing or walking

·   Aching during menses

Age Alert

As a person ages, veins dilate and stretch, increasing susceptibility to varicose veins and chronic venous insufficiency. Because the skin becomes friable and can easily break down, ulcers caused by chronic venous insufficiency may take longer to heal.

Diagnostic test results

Clinical Tip

Manual compression test detects a palpable impulse when the vein is firmly occluded at least 8″ (20.3 cm) above the point of palpation, indicating incompetent valves in the vein.

Trendelenburg's test (retrograde filling test) detects incompetent valves when the vein is occluded with the patient in the supine position and the leg is elevated 90 degrees. When the person stands (still with the vein occluded), the saphenous veins should fill slowly from below in about 30 seconds.

·   Photoplethysmography characterizes venous blood flow by noting changes in the skin's circulation.

·   Doppler ultrasonography detects the presence or absence of venous backflow in deep or superficial veins.

·   Venous outflow and reflux plethysmography detects deep vein occlusion; this test is invasive and not routinely used.

·   Ascending and descending venography demonstrates venous occlusion and patterns of collateral flow.

Treatment

·   Treatment of underlying cause (if possible), such as abdominal tumor or obesity

·   Antiembolism stockings or elastic bandages

·   Regular exercise

·   Injection of a sclerosing agent into small to medium-sized varicosities

·   Surgical stripping and ligation of severe varicose veins

·   Phlebectomy (removing the varicose vein through small incisions in the skin)

P.79

VASCULAR CHANGES IN VARICOSE VEINS

image

image