Disseminated Intravascular Coagulation (DIC)
Essentials of Diagnosis
- Underlying serious illness.
- Microangiopathic hemolytic anemia may be present,
- Hypofibrinogenemia. Thrombocytopenia, fibrin degradation products, and prolonged prothrombin time.
- Sepsis (especially with gram-negative bacteria), P. falciparum
- Severe tissue injury (especially burns and head injury), Snake bite
- Obstetric complications (amniotic fluid embolus, septic abortion, retained fetus)
- Cancer (acute promyelocytic leukemia, mucinous adenocarcinomas)
- Major hemolytic transfusion reactions.
The pathophysiology of DIC.
Symptoms and Signs:
- DIC leads to both bleeding and thrombosis.
- Bleeding is far more common than thrombosis. Bleeding may occur at any site.
- Thrombosis is most commonly manifested by digital ischemia and gangrene, but catastrophic events such as renal cortical necrosis and hemorrhagic adrenal infarction may occur.
- DIC may also secondarily produce microangiopathic hemolytic anemia > heart > lung > kidney > adrenal gland.
- Elevated fibrin degradation products (most sensitive test)
- Prolonged prothrombin time.
- Of the fibrin degradation products, the D-dimer is the most sensitive, since its cross-linking implies origin from fibrin in a clot. P/S schistocyte helmet cell
- All fibrin degradation products are cleared by the liver and thus may be elevated in hepatic dysfunction.
- All blood test (BT, CT, PT, PTT) are abnormal except clot retardation time which is normal. (LQ 2012)
- Coombs test is negative, (LQ 2012)
Table - Coagulation Disorders and Hemostasis in Liver Disease
|1. Portal hypertension - Esophageal varices|
|2. Thrombocytopenia due to|
|a. Splenomegaly b. Chronic or acute DIC|
|3. Decreased synthesis of clotting factors due to|
|a. Hepatocyte failure b. Vitamin K deficiency|
|4. Systemic fibrinolysis due to|
|a. DIC b. Dysfibrinogenemia|
|1. Decreased synthesis of coagulation inhibitors: protein C, protein S, antithrombin|
|2. Hepatocyte failure|
|3. Failure to clear activated coagulation proteins|
|C. Iatrogenic: Transfusion of prothrombin complex concentrates|
|D. Antifibrinolytic agents: e-aminocaproic acid (EACA), tranexamic acid|
Pathophysiology of disseminated intravascular coagulation.
Treatment of DIC
1. Treatment of the underlying disorder
2. Replacement therapy
- Platelet transfusion
- Fibrinogen is replaced with cryoprecipitate.
- Coagulation factor deficiency may require replacement with fresh-frozen plasma.
Extra Edge: But Heparin therapy is routinely used in the treatment of acute promyelocytic leukemia.