What is the test for intravascular coagulation?

OVERVIEW

• Disseminated intravascular coagulation (DIC) is an acquired syndrome characterized by the intravascular activation of coagulation with loss of localization arising from different causes
• It can originate from and cause damage to the microvasculature, which if sufficiently severe, can produce organ dysfunction

PATHOPHYSIOLOGY

• underlying disease process-> pro-inflammatory cytokines (activation of mononuclear and endothelial cells)-> intravascular fibrin formation-> microvascular thrombi and organ dysfunction-> consumptive intravascular coagulopathy and thrombocytopenia

  -> widespread haemorrhage

CAUSES

Include:

• shock
• sepsis
• haemolysis
• malignancy (e.g. promyelocytic leukaemia, other hematological malignancies, solid tumors)
• trauma (e.g. multi-trauma, TBI, fat embolism syndrome)
• pancreatitis
• severe hepatic failure
• burns
• major surgery
• PE
• ECMO
• transplant rejection
• transfusion reactions
• obstetric: pre-eclampsia, amniotic fluid embolism, intrauterine death, abruption
• vascular disorders (e.g. Kasabach-Merrit syndrome, large aneurysms)

CLINICAL FEATURES

• may be chronic with little overt clinical effects
• can be an acute catastrophe
• haemorrhage
• microthrombosis leading to multiorgan failure

INVESTIGATIONS

• anaemia
• prolonged APTT, INR and PT
• thrombocytopaenia (or falling platelets)
• low fibrinogen
• fragmented RBCs on blood film
• high fibrin degradation products (FDPs) / D-dimer
• low levels of plasma coagulation factors and inhibitors (if tested)

DIC score (Taylor et al, 2001)

• useful for diagnosis of DIC
• simple scoring system based on platelet count, PT, D-dimer levels and fibrinogen
• sensitivity 93% and specificity 98%
• strong independent predictor of mortality in patients with severe sepsis

DIFFERENTIAL DIAGNOSIS

Other important causes of prolonged APTT, INR and PT and low fibrinogen include:

• Primary fibrinolysis
• ‘Dilutional coagulopathy’ from massive transfusion
• Trauma-induced coagulopathy
• Post thrombolysis
• Venom-induced consumptive coagulopathy (VICC) from snake bite envenoming

MANAGEMENT

• treat cause!
• FFP for APTT and INR
• cryoprecipitate for fibrinogen (>1.0)
• platelets for thrombocytopaenia (aim > 50)
• consider FIIa
• consider heparin if not bleeding (in chronic DIC)

References and Links

• Levi M, Opal SM. Coagulation abnormalities in critically ill patients. Crit Care. 2006;10(4):222. PMC1750988.
• Taylor FBJ, Toh CH, Hoots WK, Wada H, Levi M. Towards definition, clinical and laboratory criteria, and a scoring system for disseminated intravascular coagulation. Thromb Haemost.2001;86:1327–1330. PMID: 11816725
  

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

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