Table of Contents
- Definition of Disseminated Intravascular Coagulation
- Types of Disseminated Intravascular Coagulation
- Causes of Disseminated Intravascular Coagulation
- Pathophysiology of Disseminated Intravascular Coagulation
- Clinical Features of Disseminated Intravascular Coagulation
- Diagnosis of Disseminated Intravascular Coagulation
- Treatment of Disseminated Intravascular Coagulation
- Complications of Disseminated Intravascular Coagulation
- Prognosis of Disseminated Intravascular Coagulation
Definition of Disseminated Intravascular Coagulation
Disseminated Intravascular Coagulation (DIC) is a serious medical disorder in which multiple clots are formed that can lead to permanent end-organ damage. Systemic activation of the blood coagulation occurs that results in the generation and the deposition of excess fibrin. This causes the blockage of blood vessels by the thrombi.
It leads towards multiple organ dysfunction as each and every tissue of the body needs a continuous supply of blood to remain alive and functioning. Due to excessive thrombi formation, the platelets and clotting factors become exhausted and depleted. In such a case, any case of minor bleeding will turn into a major bleeding episode.
There are two basic problems in DIC. One is the occlusion of vessels by the thrombi and the other is massive bleeding due to the utilization of all factors in the coagulation cascades. Both of them are dangerous and can cause very harmful consequences. Once the vicious cycle gets initiated, a prompt therapy is compulsory; otherwise, the person can die within few minutes of the onset of DIC.
Types of Disseminated Intravascular Coagulation
It is classified as an acute and chronic form.
The acute form
Aggressive intravascular coagulation and consumption of coagulation factors take place. The risk of organ failure is higher.
The chronic form
It is a slow compensated state when the blood is continuously exposed to low levels of stimuli. Permanent organ damage does not result from this. It mostly occurs in the cases of tumors and aortic aneurysms.
Causes of Disseminated Intravascular Coagulation
The most common cause of DIC is severe sepsis. It can be due to gram-positive bacteria, gram-negative viruses, parasites, and fungi. Trauma is also a frequent cause of DIC, especially when the SIRS (systemic inflammatory response system) gets initiated. The released inflammatory cytokines activate the coagulation pathways.
- Severe Infection
- Transfusion reactions
- Vascular abnormalities
- Hepatic failure
- Toxic reactions
- Head injuries
- Rarely: Antiphospholipid antibody syndrome
- Large Hemangioma
Pathophysiology of Disseminated Intravascular Coagulation
The slow evolving DIC often causes DVT (Deep Venous Thrombosis), PE (pulmonary embolism), and cardiac vegetations.
The rapid evolving DIC causes bleeding as a result of rapid depletion of fibrinogen and clotting factors.
The basic underlying pathology is a disruption of the balance between the Clot formation system and Fibrinolysis in the body tipping in the favour of Clot formation.
The following mechanisms play a role in the causation of disseminated intravascular Coagulation.
- When there is endothelial disruption or tissue damage, tissue factor gets exposed. This tissue factor (TF) starts the coagulation cascade and generation of thrombin. Thrombin converts fibrinogen into active fibrin and clots are formed.
- Dysfunctional anticoagulant mechanisms like the depletion of protein C and antithrombin.
- Fibrinolytic system is depressed as a result of another protein ‘plasminogen activator inhibitor’. The fibrinolytic system is important for breaking down the clots.
- The release of inflammatory cytokines.
All the above mechanisms contribute to the following results
- Increase the platelet formation and aggregation
- Activation of clotting factors
- Formation of excess thrombin
- Thrombin leads to clot formation
- Defective cleavage of clots
Clinical Features of Disseminated Intravascular Coagulation
Following are the signs and symptoms of people presenting with Disseminated Intravascular Coagulation:
- Bleeding from multiple sites in the body
- Toxic looking patient
- Renal dysfunction
- Respiratory dysfunction
- Hepatic dysfunction
- Central Nervous System Dysfunction
- Deep Venous Thrombosis
Diagnosis of Disseminated Intravascular Coagulation
There are three components of the diagnostic workup. The detailed history, physical examination, and the laboratory investigations are done.
Physical Examination is the most important step. The treatment is started on the basis of positive physical signs, while the results of the laboratory investigations are awaited. DIC is a life-threatening condition and immediate treatment is started without any delay. The signs to look for during the examination are:
Signs of hemorrhage
- Signs of localized thrombosis
- Altered consciousness
- Focal neurological deficits
- Hypotension and tachycardia
- Signs of ARDS (Acute Respiratory Distress)
- Hematemesis and haematochezia
- Skin necrosis
Diagnosis of acute form of DIC largely depends on history of suspected underlying cause (such as: sepsis, trauma or malignancy), clinical features, moderate to severe thrombocytopenia (<100,000/microL), specific labortatory findings mentioned below and finding of microangiopathic changes on blood smear.
- Complete blood count: There is thrombocytopenia.
- Activated Partial Thromboplastin Time (APTT) and Prothrombin time (PT) are prolonged.
- Clotting factors (II, V, and VIII) and Protein C is reduced.
- Fibrin Degradation Products (FDP’s) and D-Dimmers are increased.
Chronic form of DIC has lower rate of coagulation factors consuption, but enhancing synthesis of these factors, thus, there might be only moderate reduction of platelet count, normal or slightly high plasma fibrinogen, normal PT and aPTT.
Treatment of Disseminated Intravascular Coagulation
- Identify and treat the underlying cause.
- Administer Fresh Frozen Plasma: The dose is 10–15 ml/kg and it will improve the clotting factor activity by 10–15 %.
- Platelet concentrates: 10 ml per kg of platelet concentrates are given to neonates. It will raise the platelet count to 75,000–100,000/ul. The dose is 1 bag/ 5 kg for older children. It is usually indicated when platelet levels reach 10,000-20,000/microL.
- Cryoprecipitate: It provides fibrinogen and factor VIII.It is administered when fibrinogen levels drop below 100mg/dL.
- Anticoagulant therapy: using Heparin in patients who have or are at risk of venous thrombosis. It is more often used in slow developing DIC and rarely in rapidly evolving DIC.
The minimum levels required to control the bleeding are:
- Platelets should be > 40,000/ul
- Prothrombin Time < 16 seconds.
- Fibrinogen levels > 100 mg/dl
Complications of Disseminated Intravascular Coagulation
- Permanent damage to organs.
- Severe Haemorrhage
- Cardiac Tamponade
Prognosis of Disseminated Intravascular Coagulation
The prognosis of the disease is very variable depending on the cause and extent of thrombosis. An overall ‘poor prognosis’ is associated with DIC. 10–50 % of people die as a result of DIC. Sepsis-related deaths are more common than trauma-related DIC.