Introduction
- Disseminated Intravascular Coagulation (DIC) is a serious acquired disorder of the blood coagulation system.
- It involves widespread and abnormal activation of coagulation throughout the circulation.
- Excessive coagulation leads to the formation of multiple small blood clots in blood vessels.
- These clots can reduce blood flow and cause tissue and organ damage.
- Continuous clot formation consumes platelets and clotting factors.
- The consumption of these components can result in abnormal and severe bleeding.
- DIC usually develops as a complication of another serious disease or condition, rather than occurring as a primary disorder.
Definition of DIC
Disseminated Intravascular Coagulation is a pathological condition characterized by systemic activation of coagulation, resulting in widespread microvascular thrombus formation, consumption of platelets and coagulation factors, and secondary bleeding.
Pathophysiology of DIC
The basic process of DIC can be summarized as:
Underlying disease → Activation of coagulation → Thrombin formation → Fibrin deposition → Microvascular thrombosis → Consumption of platelets and clotting factors → Bleeding
Important changes
- Excessive generation of thrombin occurs.
- Fibrin is deposited in small blood vessels.
- Platelets and clotting factors are consumed.
- Natural anticoagulant mechanisms become impaired.
- Fibrinolysis is activated to varying degrees.
- Microvascular thrombosis may cause organ dysfunction.
- Consumption of coagulation components may produce bleeding.
Causes of DIC
DIC can occur in several severe clinical conditions.
Major Causes
- Severe bacterial or viral infections
- Sepsis
- Major trauma
- Severe burns
- Obstetric complications
- Placental abruption
- Amniotic fluid embolism
- Retained dead fetus
- Certain cancers, particularly acute promyelocytic leukemia
- Severe liver disease
- Shock
- Major surgery
- Severe transfusion reactions
Clinical Features
Clinical manifestations depend on whether thrombosis, bleeding, or both are predominant.
Bleeding Manifestations
- Bleeding from venipuncture sites
- Nosebleeding
- Gum bleeding
- Gastrointestinal bleeding
- Hematuria
- Excessive menstrual bleeding
- Bruising and petechiae
Thrombotic Manifestations
- Organ dysfunction
- Kidney injury
- Respiratory problems
- Neurological abnormalities
- Reduced blood flow to tissues
- Peripheral ischemia
Laboratory Findings in DIC
Laboratory investigations are essential for diagnosis and monitoring.
| Test | Typical Finding in DIC |
|---|---|
| Platelet count | Decreased |
| PT | Prolonged |
| aPTT | Prolonged |
| Fibrinogen | Decreased, although it may initially be normal or increased |
| D-dimer | Markedly increased |
| Fibrin degradation products (FDPs) | Increased |
| Peripheral smear | Schistocytes may be present |
Peripheral Blood Smear
Schistocytes (fragmented red blood cells) may be observed because red blood cells can be mechanically damaged while passing through fibrin-rich microvascular thrombi.
Diagnosis of DIC
DIC is diagnosed using a combination of clinical findings and laboratory tests rather than a single test.
Important investigations include:
- Complete blood count
- Platelet count
- Prothrombin time (PT)
- Activated partial thromboplastin time (aPTT)
- Plasma fibrinogen
- D-dimer
- Fibrin degradation products
- Peripheral blood smear
Clinical scoring systems, such as the ISTH DIC score, may be used to support diagnosis.
Treatment of DIC
The most important principle of treatment is rapid treatment of the underlying cause.
General Management
- Treat the underlying infection or disease.
- Maintain adequate circulation and organ function.
- Replace blood components when clinically indicated.
- Platelet transfusion may be considered in patients with significant bleeding and severe thrombocytopenia.
- Fresh frozen plasma may be used when there is significant bleeding with prolonged coagulation tests.
- Cryoprecipitate or fibrinogen replacement may be considered when fibrinogen is severely reduced with bleeding.
- Anticoagulation may be considered in selected patients when thrombosis predominates and bleeding risk is appropriately assessed.
Complications of DIC
- Severe bleeding
- Thrombosis
- Acute kidney injury
- Respiratory failure
- Liver dysfunction
- Neurological complications
- Tissue ischemia
- Multiple organ dysfunction syndrome (MODS)
- Death in severe cases
Clinical Significance
- DIC is a serious hematological emergency that can cause life-threatening complications.
- It may lead to both excessive clot formation and severe bleeding.
- Widespread microvascular clots can cause organ and tissue damage.
- Common laboratory findings include low platelet count and prolonged PT/aPTT.
- D-dimer and fibrin degradation products are usually increased.
- Fibrinogen levels may decrease, particularly in severe or rapidly progressing DIC.
- Early diagnosis and continuous laboratory monitoring are important.
- Prompt treatment of the underlying cause is the most important step in managing DIC.