HEMATOLOGY - coagulopathy & DIC Flashcards

EXAM 2 content

1
Q

what is hemostasis?

A

the process of arresting/stopping bleeding by forming clots at sites of vascular injury

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2
Q

what is the process of hemostasis?

A
  1. vascular injury –> transient arteriolar vasoconstriction –> limits blood flow at site
  2. damage to endothelial lining of vessels –> plate adherence, activation & formation of PLATELET PLUG = primary hemostasis

– > tissue factor works w secreted plate factors + activated platelets –> activate clotting (coagulation) system –> forms fibrin clots = secondary hemostasis
–> fibrin/plate clot contracts –> more permanent plug

–> fibrinolysis = clot retraction & clot dissolution

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3
Q

what is coagulation? what is the coagulation cascade?

A
  • coagulation = presence of all clotting factors + functioning of each component
  • component = cascades = a step by step process
  • coagulation cascade = presence of clotting factors functioning in a step by step process
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4
Q

what are the two pathways that can stimulate the coagulation cascade? what happens in them?

A
  • intrinsic pathway: activated by collagen exposure from endothelial injury = when blood vessel in damaged (tested by aPTT)
  • extrinsic pathway: activated by tissue injury when tissue factor or tissue thromboplastin in released into bloodstream (tested by PR + INR)
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5
Q

when the intrinsic or extrinsic pathway is activated, what is the clotting cascade that happens?

A

conversion of prothombin to thrombin –> thrombin acts to convert fibrinogen to fibrin –> fibrin mesh forms –> traps platelets & RBCs –> stable fibrin clot

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6
Q

what is disseminated intravascular coagulation (DIC)?

A

bleeding & thrombotic disorder bc of an underlying disease or disorder – its ALWAYS caused by something else
- infection and sepsis!
- cancer!
- trauma
- shock
- obstetrical complications
- blood transfusion reactions

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7
Q

what is the pathophysiology of DIC?

A

underlying disorder triggers proinflammatory cytokine release –> activates coagulation cascade –> microclots obstructing capillaries of organs & tissues –> organ failure –> body attempts to break down clots –> fibrin split products that inhibits clotting –> clotting factors are gone –> bleeding & hemorrhage

clot clot clot –> bleed bleed bleed
- clots –> all clotting factors are used –> bleeds

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8
Q

what are the signs of microvascular thrombosis of DIC?

A
  • neurologic: multifocal, delirium & coma
  • integumentary: focal ischemia & superficial gangrene
  • renal: oliguria, azotemia & cortical necrosis
  • pulmonary: acute respiratory distress syndrome
  • GI: paralytic ileus
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9
Q

what are the signs of hemorrhage of DIC? (develops later after all clotting factors are consumed)

A
  • neurologic: intracerebral bleeding
  • integumentary: petechiae, ecchymoses & venipuncture oozing
  • renal: hematuria
  • pulmonary: respiratory congestion, dyspnea & hemoptysis
  • mucous membranes: epistaxis & gingival oozing
  • GI: massive bleeding
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10
Q

what kind of lab findings would we see in someone with DIC? is there a definitive test?

A

NO DEFINITIVE TEST

prolonged PT & aPTT
- prothrombin time: measures clotting factors of EXTRINSIC & common pathways of coagulation
aPTT: measure clotting factors of INTRINSIC & common pathways of coagulation

  • decreased plate count – bc consumed by clotting
  • decreased fibrinogen – clotting factors consumed
  • increased d-dimer – shows ongoing hemostatic system = coagulation, clumping, fibrinolysis
  • detection of fibrin split products – produced when body tries to break down clots
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11
Q

what is the disease track of DIC? what is our goal? what is the treatment?

A

GOAL: eliminate underlying disorder –> liver can restore norm lvls of clotting factors within 24-48 hrs if eliminated

  • maintenance of organ function – fluid & oxygen
  • blood products for active bleeding or for invasive procedures
  • anticoagulants –> increase risk of bleeding
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11
Q

lets say we give anticoagulants, what if the pt starts bleeding?

A

replacement of coagulation factors, platelets, & other coagulation elements
- risk of increase thrombosis

controlling ongoing thrombosis is difficult to attain
- earlier recognized & treated –> more likely pt will survive

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