Thrombosis, Thrombophlebitis and embolism

PST 515 – Physiotherapy in disorders of blood and lymph vessels

Thrombosis

• Thrombosis is the formation, from constituents of blood, of an abnormal mass within the vascular system of a living animal. It is the formation of solid mass in circulation from the constituents of flowing blood with intact cardiovascular tree during life

• When it occurs in the deep veins, it is referred to as deep vein thrombosis (DVT)

• Thrombus is composed predominantly of fibrin and red cells

• It is a critical vascular disorder associated with morbidity and mortality.

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When a clot breaks away from the wall of a vein and travels proximally, it is called an embolus.

Mechanism/pathophysiology

• The integrity of a closed, low or high pressure circulatory system is maintained by haemostasis

• Heamostasis is the process of maintaining blood in a fluid, clot-free state in normal vasculature.

• Disruption in haemostasis leads to thrombosis

• Vessel trauma stimulates the clotting cascade. Platelets aggregate at the site particularly when venous stasis is present. Platelets and fibrin form the initial clot

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Mechanism/pathophysiology

• The thrombus propagates in the direction of the blood flow.

• Inflammation is triggered, causing tenderness, swelling, and erythema.

• Pieces of thrombus may break loose and travel through circulation-emboli.

• Fibroblasts eventually invade the thrombus, scarring vein wall and destroying valves.

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Aetiology

Venous Stasis

Endothelial damage

Hypercoagulablestate

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The formation of thrombosis is described by the Virchow’s Triad

Venous Stasis

• Venous stasis can result from• Prolonged bed rest• Leg cast• Paralysis of a limb• Spinal cord injury• Extended travel in a vehicle

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Hypercoagulable state

• Hypercoagulable state could result from:• Surgery and trauma

• Malignancy

• Increased oestrogen

• Coagulation disorders (nephrotic disorders, anti-phospholipid antibodies)

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Endothelial damage

Endothelial damage occurs when there is injury to the vascular endothelium

• Trauma

• Surgery

• Invasive procedure

• Iatrogenic cause – central venous catheters. (subclavian, internal jugular veins)

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Deep Vein Thrombosis

• Lower extremity venous thrombosis can occur in the superficial vein system (greater or small saphenous veins)or the deep vein system (popliteal, femoral, or iliac veins)

• It typically starts in the lower extremities and progress proximally to involve the popliteal, femoral and iliac system

• Deep vein Thrombosis is more dangerous than superficial thrombophlebitis

• A lower extremity DVT is a common complication after musculoskeletal injury or surgery, prolonged immobilization, or bed rest and is attributed to venous stasis, injury to and inflammation of the walls of a vein, or a hypercoagulable state of the blood

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Signs and symptoms

• In the early stages of DVT, most cases are asymptomatic with only 25% to 50% of cases having clinical manifestations

• Dull aching or severe pain, swelling, or changes in skin temperature and colour, specifically heat and redness

• Oedema may be present

• Clot in the calf be felt/detected with the Homan’s sign. (Homan’s sign sensitivity is poor)

• Deep vein thrombosis often cannot be seen or felt by the individual.

• Swelling of the leg or fever may alert a person to the presence of a DVT, especially if risk factors for DVT exist

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Thrombophlebitis

• Thrombophlebitis is a common inflammatory thrombotic process that may occur spontaneously or as a complication of medical or surgical interventions

• It is characterized by acute inflammation with partial or complete occlusion of a superficial or deep vein.

• It is inflammation due to a blood clot in a vein

• It usually occurs in the veins of the legs

• Superficial thrombophlebitis occurs in visible veins under the skin

• The area of inflammation is usually reddened, tender, warm to touch and sometimes painful.

• Patients with superficial thrombophlebitis often describe a history of a gradual onset of localised tenderness, followed by the appearance of an area of erythema along the path of a superficial vein.

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Superficial Thrombophlebitis

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Risk factors for thrombophlebitis and deep vein thrombosis• Postoperative or post-fracture immobilization

• Prolonged bed rest

• Trauma to venous vessels

• Limb paralysis

• Active malignancy (within past 6 months)

• History of deep vein thrombosis or pulmonary embolism

• Advanced age

• Obesity

• Sedentary lifestyle or extended episode of sitting during long-distance travel

• Congestive heart failure

• Use of oral contraceptives

• Pregnancy

Embolism

• A process of partial or complete obstruction of some part of the cardiovascular system by any mass carried in the circulation

• An embolus is a detached intravascular solid, liquid or gaseous mass that is carried by the blood to a site distant from origin

• When an embolus affects pulmonary circulation, it is called a pulmonary embolism, which is a potentially life-threatening disorder

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Classification of emboli

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Embolism can be classified based on the following:

• Matter of the emboli (solid , liquid, gases, foreign bodies)

• Whether it is infected on not (Sterile of Septic)

• The source of the emboli• Cardiac - left atrium and atrial appendages, infarct in the left ventricle,

vegetations of endocarditis

• Arterial - systemic arteries in the brain, spleen, kidney, intestine

• Venous - pulmonary arteries

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Classification of Embolism based on matter

• Thromboembolism (90%)

• Fat embolism

• Air embolism

• Amniotic fluid embolism

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Thromboembolism

• Embolism from a blood clot

• Thromboembolism makes up 90% of all embolism. It may be arterial or venous.

• Thromboembolism can travel to various sites – lungs, brain, kidneys, spleen

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Fat Embolism

• Obstruction of arterioles and capillaries by fat globules• Fractures of long bones

• Trauma to soft tissue e.g., adipose tissue

•

• Clinical features

• Pulmonary insufficiency - tachypnea, dyspnea, tachycardia

• Neurologic symptoms - irritability, restlessness to delirium and coma

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Air embolism

• Embolism occurs when air is introduced into venous or arterial circulation. Gas bubbles within the circulation can coalesce to form frothy masses and obstruct vascular flow. Can occur in the following situations:• Small volume of air trapped in coronary artery during bypass surgery

• Chest wall injury

• Obstetric or laparoscopy procedures

• Surgery on head and neck, cardiothoracic surgery

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Amniotic fluid embolism

• Amniotic fluid flows into ruptured uterine vessels.

• Infusion of amniotic fluid or foetal tissue into maternal circulation via a tear in placenta membranes and uterine veins. It is uncommon.

• The amniotic fluid triggers serious reaction leading to cardiorespiratory collapse and massive bleeding

• Can occur during labour or immediately post partum

• Clinical features include sudden onset of severe dyspnoea, Cyanosis, Hypotension, Shock, Seizures, Coma

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Pulmonary Embolism

• When an embolus affects pulmonary circulation, it is called a pulmonary embolism, which is a potentially life-threatening disorder

• Usually results from a DVT that becomes loose in the veins and travels to the lungs (however, pulmonary emboli can come from other sources). There, it blocks proper blood flow to the lungs and decreases oxygen levels in the body.

• It is Common in hospitalised and bed ridden patients

• Saddle emboli - Large thrombus gets impacted at bifurcation of pulmonary artery

• Multiple emboli – in different sites

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Sources of pulmonary embolism

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Signs/symptoms

• Sudden onset of shortness of breath

• Chest pain or discomforts that worsens with deep breath or cough

• Dizziness/ light-headedness

• Fainting rapid pulse

• Haemoptysis

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Consequences of pulmonary embolism

• Resolution – majority of small pulmonary emboli (60-80%) are resolved by fibrinolytic activity

• Acute cor pulmonale – Numerous small emboli may obstruct most of the pulmonary circulation resulting in acute right heart failure

• Pulmonary infarction: Obstruction of relatively small sized pulmonary arterial branches may result in pulmonary infarction

• Pulmonary haemorrhage

• Pulmonary hypertension,

• Chronic cor pulmonale and pulmonary arteriosclerosis

• Sudden death

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Examination and assessment

• A complete history and systems review help determine the presence of a venous disorder.

• Assessment includes a comprehensive integumentary and neuromuscular examination that includes skin integrity, mobility, colour, texture, temperature, vital signs including peripheral pulses, sensation, pain, functional mobility, ROM, strength, and cardiopulmonary endurance.

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Examination and assessment

Some specific tests to determine venous sufficiency are:

• Girth measurements of the upper or lower extremities

• Homans’ sign

• Response to compression of the limb with a blood pressure cuff

• Doppler ultrasonography

• Venous duplex screening/scanning

• Venography

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Girth Measurements

• Circumferential measurements of the involved and uninvolved limbs are taken to determine the presence and extent of oedema.

• Homan’s sign• With the patient supine and the knee extended, passively

dorsiflex the ankle and gently squeeze the calf muscles. If pain occurs in the calf, Homans’ sign is positive, indicating the possible presence of a DVT. Homan’s sign is not a definitive test.

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Application of a Blood Pressure Cuff Around the Calf

• Procedure. Inflate the cuff gradually until the patient experiences calf pain. A patient with acute thrombophlebitis usually cannot tolerate pressures above 40 mmHG

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Prevention• Prophylactic use of anticoagulant therapy for the high-risk patient (e.g., the

patient who has undergone lower extremity surgery or who is on bed rest)

• Early mobilization and ambulation

• Elevating the legs while lying supine and on a footstool when sitting

• No prolonged periods of sitting, especially for the patient with a long-leg cast

• Ankle pump exercises (active dorsiflexion, plantarflexion, and circumduction of the ankle) regularly

• Use of compression stockings to support the walls of the veins and minimize venous pooling

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