2 DefinitionMucocutaneous hemorrhage is caused by the abnormalities of hemostasis(止血) and /or coagulation(凝血), characterized by local or extensive mucocutaneous hemorrhage derived from capillary. The bleeding is usually spontaneous or from slight trauma.
3 Hemostasis/coagulation Hemostasis/coagulation is the body's normal physiological response for the prevention and stopping of bleeding/hemorrhage.
4 Primary and secondary hemostasis are closely linked HemotasisPrimary hemostasis---platelet plug formation at sites of injurySecondary hemostasis---plasma coagulation system reaction resulting in fibrin formationPrimary and secondary hemostasis are closely linked
6 Etiology & Pathogenesis Vessel wall disordersAbnormalities of blood platelets— Quantitative platelets defects— Qualitative platelets defectsDisturbance of coagulation in circulation— Deficiency of coagulation factorsIncrease of anti-coagulation substancesHyperfunction of fibrinolysis(纤维蛋白溶解)
9 Constriction of capillary playing the role of hemostasis local vascular constrictionsealing the damaged vascular endotheliumreducing blood flow
10 Vascular wall disorders Damage to capillary endotheliumAbnormalities in the vascular subendothelial matrixDefect of extravascular connective tissues that support blood vesselsFormation of abnormal blood vessels.
11 Defects on Capillary Wall HereditaryTelangioectasia(毛细血管扩张);AcquiredAllergic purpura(过敏性紫癜);Senile purpuraNon- thrombocytopenic purpura— Severe infection— Vitamin C deficiency— Uremia
12 Vitamin C is needed to synthesize hydroxyproline(羟脯氨酸), an essential constituent of collagen
13 Cushing's syndrome excess production of glucocorticoids develop generalized protein wastingatrophy of the supporting connective tissue around blood vesselsskin bleeding or easy bruising
14 Ageing causes a similar atrophy of perivascular connective tissues Senile purpuraAgeing causes a similar atrophy of perivascular connective tissues
15 In this situation,BT and CT are normal,but capillary fragility test is positive.
17 Blood platelets function in primary hemostasis platelet adhesion and aggregationPlatelet activation from thromboxane A further aggregates platelets (to form the white thrombus ) and enhances vasoconstrictionplatelet secretion activated platelets secrete platelet agents, 5-HT and coagulators participating in the coagulation process and facilitate the clot constriction.
19 Some of the products secreted by platelets are depicted as: ADP, adenosine diphosphate(腺苷二磷酸);PDGF, platelet-derived growth factor(血小板源性生长因子);vWF, von Willebrand factor.
20 arachidonic acid(花生四烯酸); cyclooxygenase(环氧合酶); endoperoxide(内皮过氧化酶); Generation of thromboxane A2 in platelets and prostacyclin (PGI2) in endothelial cells.arachidonic acid(花生四烯酸);cyclooxygenase(环氧合酶);endoperoxide(内皮过氧化酶);thromboxane(血栓素);prostacyclin(前列环素);
21 Abnormalities of Blood Platelets Quantitative platelets defects— BPC is low, as thrombocytopenia(血小板减少症) with various causesQualitative platelets defects— Platelets dysfunction, as thrombasthenia(血小板无力)
29 Congenital plasma coagulation defects Hemophilia A-dificiency of factor VIIIHemophilia B-dificiency of factor IXHemophilia C-dificiency of factor XIDeficiencies in factors V, VII, X, and prothrombin (factor II)
30 Acquired coagulation disorders Vitamin K deficiency(II, VII,IX, X)Liver diseaseDisseminated intravascular coagulation (DIC)Complications of anticoagulant therapy
31 Vitamin K deficiencyServes as a cofactor in the enzymatic carboxylation of glutamic acid(谷氨酸) residues on prothrombin complex proteins (factors II, VII, IX, X; proteins C and S)Plasma levels of all the prothrombin complex proteins decrease.
32 Vitamin K Deficiency Inadequate dietary intake Intestinal mal-absorptionLoss of storage sites due to hepatocellular disease
33 Coagulation Disorders in Liver Disease Decreased production of coagulation proteins(II,VII,IX,X), and fibrinogen(factor I) and factor VSome degree of vitamin K deficiency“Hypercoagulable" and predisposed to developing DIC or systemic fibrinolysis.
34 Lab test of coagulation defect PTPTTCTplatelet countfibrinogen determination
38 Defects in the fibrinolytic system a2 plasmin inhibitor deficiency or plasminogen activator inhibitor (PAI) 1Secondary fibrinolysis accompanying DIC
39 Increase of anti-coagulation substances the increase of heparan anticogulants or the over-dosage of anticoagulants.
40 Types of Mucocutaneous hemorrhage Petechia(出血点;瘀点): pinpoint hemorrhage<2mm in diameterPurpura(紫癜): > 3- 5mm in diameterEcchymosis(瘀斑): common bruise, >5mmHematoma(血肿): local elevation and fluctuationEpistaxis(鼻出血)Bleeding in skin, mucous membrane, joint cavity and viscera(内脏).
42 Approach to patients with mucocutaneous hemorrhage
43 History-taking Age,male or female,onset of the disease Spontaneous or following traumaPast history of bleeding tendency, such as bleeding after tooth extraction,Liver diseaseA family history of bleeding and bleeding from multiple sites, repeated episodesA record of drug ingestion
44 Physical examinationBleeding should be traced over whole body, sometimes including urine and stool.In addition, the jaundice and the size of liver and spleen should be noted.
45 Bleeding from a platelet disorder Bleeding sites localized to superficial sites such as the skin and mucous membranesImmediately after trauma or surgeryReadily controlled by local measures
46 Bleeding from plasma coagulation defects Bleeding sites: in deep subcutaneous tissues, muscles, joints, or body cavitiestime: hours or days after injuryUnaffected by local therapy
47 Laboratory routine tests Blood routineBlood platelet countBleeding time (a sensitive measure of platelet function)Prothrombin time (PT, screens the extrinsic limb of the coagulation system)Coagulation timeBone marrow studyCoagulation factors determinationFibrinogen determination.Screening testsSpecific tests