105. Thrombosis - classification, etiology, pathogenesis, clinical manifestations.

Thrombosis - classification, etiology, pathogenesis, and clinical manifestations.

Thrombosis is the formation of a solid mass (thrombus) from blood constituents within the vascular system during life.

Classification

1. 1 By location

1. 2 By composition

Etiology

Virchow’s triad

1. 1 Endothelial injury

Atherosclerosis.

Hypertension.

Inflammation, vasculitis.

Trauma, surgery.

1. 2 Abnormal blood flow

Stasis (e.g., prolonged immobilization → DVT).

Turbulence (e.g., aneurysms, valvular heart disease).

1. 3 Hypercoagulability

Inherited:

• Factor V Leiden mutation.
• Prothrombin gene mutation.
• Protein C, S, or antithrombin III deficiency.

Acquired:

• Malignancy.
• Pregnancy.
• Oral contraceptives.
• Nephrotic syndrome.
• Antiphospholipid syndrome.

Pathogenesis

1. Endothelial injury or dysfunction exposes subendothelial collagen and tissue factor → platelet adhesion and activation.
2. Coagulation cascade activation → fibrin mesh formation → further platelet aggregation → thrombus growth.
3. Thrombus may:

Obstruct vessel → ischemia/ infarction. - coronoryartery

Embolize → distant occlusion (e.g., pulmonary embolism from DVT).

Clinical manifestations

Arterial thrombosis

Sudden ischemia → infarction.

Myocardial infarction: chest pain, dyspnea, diaphoresis.

Stroke: sudden neurological deficits.

Limb ischemia: pain, pallor, pulselessness, paresthesia, paralysis ("5 Ps").

Venous thrombosis (e.g., DVT)

Swelling, pain, warmth, redness of affected limb.

Positive Homan’s sign (calf pain on dorsiflexion, not very specific).

Cardiac thrombi

May embolize to systemic circulation → stroke, organ infarcts.

Possible fates of a thrombus