Disseminated Intravascular Coagulation

Disseminated Intravascular Coagulation



Basic Information image



Definition


Disseminated intravascular coagulation (DIC) is a thrombohemorrhagic syndrome resulting from the inappropriate systemic activation of the coagulation system caused by systemic inflammation. Disproportionate endothelial cell activation causes intravascular fibrin formation and microangiopathic thrombosis, resulting in organ ischemia, necrosis, reperfusion injury, and multiorgan dysfunction. Concurrent widespread hemorrhage may occur because of consumption of coagulation factors, fibrinogen, and platelets.



Synonyms




• DIC


• Consumptive coagulopathy


• Dysfibrinogen syndrome



Epidemiology



Risk Factors


Any primary disorder that causes systemic inflammation, including endotoxemia, sepsis, shock, trauma, hemorrhage, neonatal hypoxic-ischemic encephalopathy syndrome, local infections (endometritis), envenomation, neoplasia, immune-mediated disease (purpura hemorrhagica), gastrointestinal disease (large colon volvulus, colitis), and heatstroke



Associated Conditions and Disorders




• A component of the massive and inappropriate inflammatory response resulting from traumatic or septic conditions


• Has been linked to endotoxemia



Clinical Presentation



Disease Forms/Subtypes




• DIC progresses through three continuous, overlapping stages:


• Hypercoagulation: Not noted clinically

• Compensated or subclinical stage: May see alterations in coagulation profiles or end-organ dysfunction

• Fulminant or uncompensated stage: Fulminant coagulopathy and signs of hemorrhage


History, Chief Complaint




• Typically indistinct


• Varies based on the primary disease process


• Hemorrhage noted in end-stage DIC



Physical Exam Findings




• Depend on primary disease process, the location and severity of fibrin deposition, and the extent of clotting factor depletion


• May not see overt clinical signs in patients with subclinical DIC


• Pale mucous membranes

• Tachycardia

• Tachypnea

• Petechia, progressing to diffuse bruising (ecchymosis)

• Hematuria

• Melena

• Epistaxis

• Icterus

• Venous thrombosis

• Colic


Etiology and Pathophysiology




• DIC may be initiated by one of three methods.


• Procoagulants (tissue factor or a specific neoplastic procoagulant) expressed by adenocarcinoma or lymphoma directly stimulate coagulation pathways.

• Bacterial endotoxins (gram-negative bacteria) or exotoxins (gram-positive bacteria) present in severe sepsis, stimulating the release of inflammatory cytokines that initiate an imbalance of coagulation.

• Trauma, releasing inflammatory mediators and tissue factor, and causing direct damage to endothelial cells that initiates a systemic inflammatory response.

• In systemic inflammation, the disrupted endothelium and activated mononuclear cells produce proinflammatory cytokines that initiate an imbalance of coagulation.


• Tissue factor is expressed by mononuclear cells and endothelium, initiating the extrinsic coagulation pathway.

• Intravascular fibrin formation is promoted because of disruption of anticoagulant mechanisms.

• Anticoagulation pathways are inhibited by downregulation of antithrombin III (ATIII), thrombomodulin, and protein C.


• Abnormal coagulation is promoted by consumption of anticlotting factors, including thrombomodulin and antithrombin III.


• Fibrinolysis is inhibited by plasminogen activator inhibitor type 1 released by the endothelium.

• Thrombocytopenia and consumption of coagulation factors may occur as DIC progresses, initiating the hemorrhagic phase.

• Thrombosis causes local ischemia, acidosis, necrosis, and reperfusion injury, which perpetuates DIC and may lead to multiorgan failure.



Diagnosis image



Differential Diagnosis




• Anticoagulant or rodenticide exposure


• Severe thrombocytopenia


• Inherited or acquired platelet dysfunction


• Hydroxyethyl starch administration (prolonged clotting times)


• Liver failure

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Jul 24, 2016 | Posted by in SMALL ANIMAL | Comments Off on Disseminated Intravascular Coagulation

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