Chapter 19_2 flashcards
(23 cards)
Deep Venous Thromboembolism (DVT): Pathophysiology & Progression to PE
A thrombus (clot) forms in a deep leg vein, often at an area of inflammation. This DVT can detach and travel (as an embolus) up the inferior vena cava -> right atrium -> right ventricle -> pulmonary artery, where it becomes a Pulmonary Embolism (PE), obstructing lung perfusion.
DVT: Clinical Presentation
May be silent. If symptomatic: Unilateral leg pain (often cramp-like in calf), redness, ropiness, tenderness, and/or warmth over the vein. Calf may be swollen.
Pulmonary Embolism (PE): Clinical Presentation
Can be silent and fatal. Symptoms: Dyspnea (most common), chest pain, tachycardia, hypotension, hemoptysis (coughing up blood), syncope.
Homan’s Sign for DVT
Calf pain elicited by dorsiflexion of the foot. Can occur in DVT, but present in only ~50% of DVT cases and can be positive in other conditions; not a reliable standalone diagnostic sign.
Diagnosis of DVT: Wells Criteria & D-dimer
Wells criteria score estimates DVT probability. Negative D-dimer PLUS Wells score <2 helps rule out DVT. Positive D-dimer (fibrin degradation products >500 ng/mL) and Wells score >=2 requires further imaging.
Diagnosis of DVT: Imaging
Duplex ultrasonography (ultrasound + Doppler) is the principal diagnostic test. CT venography and MRI can also be used. Impedance plethysmography (IPG) measures blood volume.
Diagnosis of PE: Imaging
High-resolution multidetector computed tomographic angiography (MDCTA) is the best test. V-Q scan (ventilation-perfusion scan) is a second-line test.
DVT Treatment: Preventive Strategies
Sequential venous compression devices, antiembolism stockings (TEDs), elevation of extremities, early ambulation/leg exercises.
DVT Treatment: Anticoagulants (Purpose & Monitoring)
Prolong clotting time to prevent further clot formation or extension. Medications: Factor Xa inhibitors, direct thrombin inhibitors, Low Molecular Weight Heparin (LMWH), Unfractionated Heparin (UFH), Warfarin. Goal: Clotting time (PT/aPTT) 1.5 to 2.5 times normal. Warfarin goal INR: 2-3. DOACs (Factor Xa inhibitors, direct thrombin inhibitors) and LMWH generally do not require routine PT/INR monitoring.
DVT/PE Treatment: Thrombolytic Agents (“Clot Busters”)
Dissolve existing clots (e.g., tPA). Used for significant DVT or PE, especially if hemodynamically unstable. Only for patients with no significant bleeding risk.
DVT/PE Treatment: Inferior Vena Cava (IVC) Filter (Greenfield Filter)
Blocks clots from lower extremities from traveling to pulmonary circulation. Used for contraindication to anticoagulants or recurrent VTE despite anticoagulation.
DVT/PE Treatment: Thrombectomy
Surgical removal of a thrombus. May be used if other treatments fail or if anticoagulation risk is too high.
Chronic Venous Insufficiency (CVI): Pathophysiology
Damage to valves in deep leg veins (due to trauma, obesity, pregnancy, prolonged standing) impairs venous return -> retrograde flow -> venous stasis -> high venous pressure -> fluid leaks into interstitium (edema) -> impaired waste removal & healing.
CVI: Clinical Presentation
Shiny skin, dusky discoloration (stasis dermatitis from hemosiderin buildup), edema, poor healing, reduced/absent hair distribution. Legs feel heavy/achy, especially after prolonged standing; symptoms relieved by elevation. Telangiectasias, corona phlebectatica, lipodermatosclerosis.
CVI: Diagnosis
Doppler ultrasonography (assesses blood flow), Photoplethysmography (PPG - emits light to determine blood volume), Venography (dye study for occlusions/collateral flow). CEAP classification system used for severity.
CVI: Treatment
Gradient compression stockings, pneumatic compression devices. Anticoagulant/antiplatelet meds. Catheter-delivered thrombolytics. Venoablation (sclerotherapy, radiofrequency ablation RFA, endovenous laser therapy EVLT) to remove reflux pathways. Surgical options for severe cases (ligation/stripping, bypass, valve reconstruction).
Varicose Veins: Definition & Pathophysiology
Abnormally dilated, tortuous superficial veins, usually in legs. Due to valvular incompetence from high pressure in superficial veins (prolonged standing/sitting, pregnancy, obesity), weakening valves. Progesterone in females can relax vein walls.
Varicose Veins: Epidemiology & Symptoms
More common in women, prevalence increases with age. Symptoms: Heaviness, fullness, aching, muscle cramps, itching in legs. Visible tortuous blue/purple veins.
Varicose Veins: Diagnosis & Treatment
Diagnosis: Clinical examination, Duplex ultrasound (esp. great saphenous vein). Treatment: Sclerotherapy (injecting sclerosing substance), endovenous ablation (laser/radiofrequency), surgical removal (ligation/stripping). Elastic stockings.
Venous Ulcers (Venous Stasis Ulcers): Cause & Location
Wounds in lower extremities due to trauma or pressure in areas of venous insufficiency. Caused by sluggish circulation, poor tissue oxygenation/nutrition, impaired waste removal. Common site: Medial malleolus (above ankle).
Venous Ulcers: Clinical Presentation & Risk Factors
Dark red ulcer, uneven margin, painful, often with significant edema and drainage. Surrounding skin shows CVI signs (stasis dermatitis, telangiectasias). Risk Factors: Age >55, family Hx of CVI, obesity, Hx of DVT/PE, immobility, multiple pregnancies.
Venous Ulcers vs. Arterial Ulcers: Key Differences (Table)
Venous: Cause-pooling of blood, increased venous pressure. Appearance-shallow, superficial, irregular shape, usually medial ankle, painful from edema/phlebitis, often drainage. Leg warm, pulses present. Arterial: Cause-insufficient arterial blood supply (ischemia). Appearance-punched out, smooth edges, often lateral foot/toes, pain at night relieved by dependency. Leg cool, pale, shiny, hairless, minimal drainage, pulses diminished/absent.
Venous Ulcers: Diagnosis & Treatment
Diagnosis: Clinical exam, Duplex ultrasound (assess venous reflux/obstruction), ABI (rule out arterial disease). Treatment: Lifestyle mods (avoid prolonged standing, exercise, compression), wound care (antibiotic dressings, débridement), growth factors, pentoxifylline. Venous ablation/surgery to correct reflux. Skin grafting for large ulcers.
