Coagulation
Acquired bleeding disorders
Disseminated intravascular coagulation (DIC)
Topic Completed: 1 August 2010
Minor changes: 15 September 2020
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PubMed Search: Disseminated intravascular coagulation [title]
Table of Contents
Definition / general | Diagrams / tables | Epidemiology | Clinical features | Laboratory | Prognostic factors | Case reports | Treatment | Differential diagnosisCite this page: Crookston K, Rosenbaum LS, Gober-Wilcox J. Disseminated intravascular coagulation (DIC). PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/coagulationDIC.html. Accessed January 17th, 2021.
Definition / general
- A common acquired syndrome arising from various causes (see etiology below), characterized by massive, sustained and excessive activation of coagulation with the eventual inundation (overwhelming) of the anticoagulant and fibrinolytic systems
- Leads to disseminated microthrombi and tissue ischemia; consumption of platelets, coagulation factors and natural anticoagulants; and variable bleeding
- Activation of inflammatory pathways via cytokines also plays a role
- Ultimately free, circulating, unopposed thrombin and plasmin are generated (the two key agents responsible for DIC) which then leads to:
- Activation and consumption of platelets, coagulation factors, fibrinogen and fibrin
- Consumption and depletion of anticoagulant proteins (protein C, protein S and antithrombin)
- Generation of D-dimers and fibrin degradation productsn
- Formation of microthrombi leading to tissue ischemia (large thrombi can also be formed, particularly in cancer patients)
- Schistocytes (fragmented red blood cells) are formed as red blood cells are severed flowing through fibrin strands (microthrombi within vasculature)
- Variable bleeding
Diagrams / tables
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Key events in DIC
Epidemiology
- 1% of hospitalized patients are estimated to develop DIC
- 20% of patients with Acute Respiratory Distress Syndrome (ARDS) develop DIC and 20% of patients with DIC develop ARDS
- 20% of patients with gram-negative sepsis develop DIC
- Other causes:
- Infection / sepsis: most common cause, includes bacterial, viral, fungal, rickettsial and protozoal organisms
- Tissue damage: trauma, burns
- Malignancy: solid and hematologic
- Obstetric complications: abruptio placentae, retained dead fetus syndrome, preeclampsia / eclampsia, amniotic fluid embolism, acute fatty liver of pregnancy, septic abortion
- Miscellaneous: near drowning, fat embolism, snake bites, aortic aneurism, acute hemolytic transfusion reaction, adult respiratory distress syndrome, giant hemangioma, homozygous protein C deficiency)
Clinical features
- Patients can have either bleeding or thrombosis or both
- Septic patients are more likely to have thrombosis than bleeding
- If severe and prolonged, will eventually lead to multiorgan dysfunction/failure
- Causes of DIC can be acute (meningococcemia) or chronic (retained dead fetus), localized (abdominal aortic aneurysm) or systemic (acute promyelocytic leukemia)
- Chronic causes of DIC are typically malignancy, liver disease, retained dead fetus syndrome, abdominal aortic aneurysm, giant hemangioma and head trauma
- Bleeding can present as surgical site, venipuncture site or mucocutaneous bleeding (most common)
- Gastrointestinal bleeding, CNS bleeding, hematuria or ecchymoses
- Thrombosis can present as purpura fulminans (manifestation of subdermal microthrombi with skin necrosis)
- Cold, pulseless limb
- Sudden loss of vision
- Oliguria
- Mental status changes, seizures, behavioral changes or adrenal insufficiency
Laboratory
- Prolonged PT and PTT
- Elevated D-dimers (Am J Clin Pathol 2004;122:178) and other fibrin degradation products (but D-dimer may be falsely positive in HIV+ Castleman’s disease due to interference from monoclonal gammopathy (Arch Pathol Lab Med 2004;128:328)
- Fall in platelet count (usually not lower than 30,000 - 40,000 x 109/L)
- Drop in fibrinogen
- Presence of schistocytes on peripheral blood smear (not specific for DIC)
- With chronic causes, fibrinogen and platelets may actually be elevated as acute phase reactants
- All coagulation factors may be variably decreased due to factor activation and consumption
- Multiorgan dysfunction may manifest as elevated cardiac enzymes or elevated BUN / creatinine
- Baseline coagulation studies and serial follow-up are needed to follow the trends
Prognostic factors
- One multicenter study of critically ill patients with DIC found that the 28 day mortality was 21.9%, which was significantly higher than non-DIC patients (11.2%) (Crit Care Med 2008;36:145)
- Another study found the mortality rate was significantly higher in sepsis patients than trauma patients (Thromb Haemost 2008;100:1099)
Case reports
- 30 year old woman with DIC due to amniotic fluid embolism (Arch Pathol Lab Med 2002;126:869)
Treatment
- Treat underlying disease
- Keep fibrinogen levels above 100 mg/dL with cryoprecipitate or fresh frozen plasma
- Monitor PT, PTT, platelet count, fibrinogen and possibly antithrombin levels
- If bleeding predominates, replace coagulation factors and fibrinogen with fresh frozen plasma (FFP) and cryoprecipitate
- Consider plasmapheresis, platelet-transfusions and immunoabsorption
- If platelet count is lower than 50,000 x 109/L with active bleeding, or lower than 10,000 x 109/L, give platelet infusion
- If thrombosis predominates (chronic DIC), heparinization should be considered
Differential diagnosis
- Dilutional coagulopathy: may coexist with DIC
- HELLP syndrome (H → hemolysis, EL → elevated liver enzymes, LP → low platelets)
- Can also degenerate to DIC
- Severe hepatic cirrhosis
- TTP / HUS
