Disseminated Intravascular Coagulation.ppt

1、Disseminated Intravascular Coagulation(DIC),Department of Pathophysiology Shanghai Jiao-Tong University School of Medicine,Blood has a complex mechanism to keep the balance between coagulation and anticoagulation by which blood maintains its fluidity. The process of haemostasis involves spasm of inj

2、ured vessels, restriction of blood flow, formation of short-term platelet plug to seal minor vessels and formation of strong fibrin clot, at last thrombus formation which closes the wound. The thrombus may be dissolved as soon as the injured vessel has healed in order to restore tissue perfusion.,In

3、troducton,Vessel wall Platelets Coagulation factors,Cellular system: Monocyte/ Macrophage Anticoagulants in plasma（TFPI,AT,heparin co-factor II ） Protein C system Fibrinolytic system,Coagulation factors VII, IX, and X; proteins C and S), whereas other parameters remain normal. Patients with hepatic

4、failure may present with the entire spectrum of factor deficiencies and may even develop DIC. Patients with liver cirrhosis have a wide spectrum of abnormalities. Except for factor VIII:C and von Willebrand factor, all procoagulant and inhibitory factors are decreased, which is a reflection of impai

5、red protein synthesis. Abnormal fibrinogen and prothrombin molecules can be identified. Platelets are quantitatively and qualitatively altered, and most patients develop DIC.,Hepatic dysfunction,Hypercoagulable state,It has been found that the platelet and several kinds of clotting factors (factor I

6、, II, VII, VIII, IX and X, etc.) in blood are increased, while the substances with the action of anticoagulation and with the activity of fibrinolysis are deceased. For instance, the blood in pregnancy after 4 months bigins to increase coagulability, which is most marked in the terminal stage of pre

7、gnancy. Therefore the incidence of DIC is elevated in obstetrical accidents. In addition, acidosis, common in some patients, promotes the activation of clotting cascade by reducing the pH of the blood.,Shock usually accompanies disorder of microcirculation which is manifested by stasis of blood flow

8、, aggregation of blood cells and appearance of sludging, stasis of the microcirculation permits activated clotting factors to accumulated in one region making it easier to develop into a state of DIC. The stasis of blood in giant hemangioma may somehow contribute to the development of DIC.,Disorder

9、of microcirculation,Inhibition of fibrinolysis,Aging, smoking, pregnandiacy, diabetes. Using antifibrinolytic agents like EACA and PAMBA,Main Features of DIC,Include petechiae and purpura (found in most patients), hemorrhagic bullae, wound bleeding; especially oozing from a surgical or traumatic wou

10、nd is common in patients who have undergone surgery or suffered trauma. Oozing from venipuncture sites or intraarterial lines is another common finding. Large subcutaneous hematomas and deep tissue bleeding are also often seen. The average patient with DIC usually bleeds from at least three unrelate

11、d sites and any combination may be seen. Bleeding causes: Clotting factors consumption FDP generation Activation of fibrinolytic system Vessel damage,Bleeding,Excess bleeding Thrombus formation results in a diminished return of venous blood to the heart Activation of the kinin system leads to increa

12、sed vascular permeability, hypotension, andshock Creation of FDP result in enhanced vasodilation Myocardial infarction,Shock,End-organ damage / failure,Impaired blood flow caused by microvascular thrombosis Ischemia reperfusion injury Systemic inflammatory response syndrom Multiple organ dysfunction

13、 syndrome,Pathogenesis,Kidneys renal damage seen in 25% of DIC cases in one series Liver hepatic dysfunction in 19% Lungs respiratory dysfunction in 16%,A disorder in which narrowing or obstruction of small blood vessels results in distortion and fragmentation of erythrocytes, hemolysis, and anemia.

14、 It is identified by the finding of anaemia and schistocytes (bite cells) on microscopy of the blood film.,Microangiopathic hemolytic anemia,Types and stages of DIC,Stages,Hypercoagulable stage Hypocoagulable stage Secondary fibrinolytic stage,Activation of Coagulation,Fibrin monomer (FM),Secondary

15、fibrinolysis,FDP (X fragment),soluble fibrin monomer complex（SFMC）,Protamine Sulfate,FM,polymerization,X fragment,positive 3P Test,Plasma Protamine Paracoagulation,D-dimer formation,Types,The form of DIC depends on the rapidity and force of the initiating event, leading to the two primary forms of D

16、IC: Acute decompensated DIC Chronic compensated DIC Compensated DIC: When the stimulus for coagulation is mild, the liver can increase production of clotting factors to up to 5 times the normal rate, in an effort to maintain plasma levels. Similarly, platelet production can increase up to 10 times.

17、Thus, although coagulation and fibrinolysis are in progress, platelet counts and fibrinogen levels may be normal or only marpinally reduced. These patients rarely bleed spontaneously or from minor trauma, but have severe haemorrhage if subjected to surgery.,Treatment of DIC,Treatment of DIC,Cornerstone of management is the treatment of the underlying illness Supportive management with Disruption of coagulation cascade using “lower dose” heparin-treatment, administration of ATIII