When the normal hemostatic mechanism fails, major hemorrhage may follow minor trauma or may arise apparently spontaneously.
[Normal hematostasis]
Normal coagulation is best described according to its major components:
1.
vessel wall
2.
platelet function
3.
coagulation factor cascade
4.
clot inhibition/lysis
[Classification]
1.
Hemorrhagic disorders due to functional abnormalities of vascular wall.
(1) Hereditary: Hereditary hemorrhagic telangiectasia, hereditary disorders of connective tissue such as Ehlers-Danlos syndrome.
(2) Secondary: infections, chemical factors or drugs, disorders of metabolism
(Vitamin C or P deficiency), pathological changes of vascular wall (atherosclerosis), connective tissue diseases.
(3) Allergy: allergic purpura.
(4) Other purpuras: purpura simplex, senile purpura, mechanic purpura, paraproteinemia.
2.Platelet abnormalities
(1) Thrombocytopenia: ① Diminished or defective platelet production: aplastic anemia, marrow infiltration (carcinoma, leukemia, myelofibrosis, tuberculosis, etc), infections, drugs that act on platelet production (alcohol, thiazide diuretics).
②
Enhanced platelet destruction: idiopathic thrombocytopenic purpura, drug-induced, thrombotic thrombocytopenic purpura. ③ Sequestration of platelets: hypersplenism.
(2) Thrombocytosis: ① Primary: essential thrombocythemia.
② Secondary: infections, injury, post-splenectomy chronic myelocytic leukemia, other myeloproliferative disorders (such as polycythemia vera).
(3) Functional abnormalities of platelets: ① Congenital: thrombasthenia, giant

platelet syndrome (Bernard-Soulier syndrome).
②
Acquired: due to drugs, uremia, liver diseases, dysproteinemias.
3.Coagulation disorders due to coagulation factor deficiencies.
(1) Congenital: hemophilia A (F Ⅷ deficiency), hemophilia B (F Ⅸ deficiency),factor Ⅺ deficiency (formerly hemophilia C), hypothrombinogenemia, hypofibrinogenemia, von Willebrand’s disease, other coagulation factors deficiency, including deficiency of activated-protein C inhibitor structural abnormalities.
(2) Acquired: Vitamin K deficiency, severe liver diseases, drugs (dicumarol), disseminated intravascular coagulation (DIC) etc.
4.Hyperfibrinolysis:
(1) Primary: Congenital deficiency of α 2 antiplasmin, clinical use of urokinase, liver diseases, liberation of tissue plasminogen activator into the circulation.
(2) Secondary: DIC.
5.
Circulating anticoagulants: antibodies against F Ⅷ , Ⅸ , thromboplastin, thrombin, heparinoid anticoagulant.
[Etiological diagnosis]
1.
History: family history, age at onset, hemorrhagic tendency, hemorrhagic manifestation since childhood, marriage (consanguinity). History of medication, diseases.
2.
Symptoms and signs: petechia, ecchymosis, hematoma, hemarthrosis, large ecchymosis, solitary or at multiple sites.
3.
Laboratory examinations
(1) Screening tests: platelet count, bleeding time, clot retraction test, capillary frangibility test, clotting time, activated partial thromboplastin time, prothrombin time (one stage method), thrombin time.
(2) Special tests for classifying the hemorrhagic disease:
① Disorders due to platelet abnormalities: megakaryocytes in marrow, morphology of platelets, clumping of platelets, adhesion test, aggregation test induced by ADP, adrenaline collagen, arachidonic acid, analysis of platelet glycoproteins etc.

②
Disorders due to coagulation factors deficiency: correction tests, measurement of different factor antigens and coagulant activities.
③ Disorders due to hyperfibrinolysis: euglobulin lysis test (ELT), fibrin (fibrinogen) degradation products (FDP), 3P test.
④ Disorders due to anticoagulants: cross correction test of recalcified time test.
[Treatments of hemorrhagic disorders]
1.
Etiological treatment and prevention
2.
Treatment according to pathophysiology
(1) Drugs decreasing the capillary fragility: Rutin, Vitamin C, adrenosem.
(2) Drugs used in thrombocytopenia, adrenal corticosteroid for immunothrombocyto- penia.
(3) Replacement therapy in congenital coagulation factors deficiencies: Vitamin K in acquired deficiency of Vitamin K dependent factors.
(4) Antifibrinolysis drugs: ε -aminocaproic acid (EACA), para-aminomethylbenzoic acid (PAMBA), tranexamic acid (t-AMCHA).
(5) Anticoagulants: immunosuppressive drugs for antibodies, protamine sulfate for heparinoid anticoagulants.