What causes bleeding in Disseminated Intravascular Coagulation (DIC)?

From the Guidelines

Bleeding in Disseminated Intravascular Coagulation (DIC) occurs due to the consumption of platelets and clotting factors, leading to a paradoxical situation where excessive clotting ultimately results in bleeding. This condition is characterized by the widespread activation of the blood clotting system, which forms numerous small blood clots in blood vessels, depleting clotting factors and platelets faster than the body can replace them 1. The initial trigger, such as severe infection, trauma, or malignancy, activates the coagulation cascade, leading to a complex interplay between coagulation and fibrinolysis. Key factors contributing to bleeding in DIC include:

• Depletion of platelets and clotting factors due to excessive clotting
• Activation of the fibrinolytic system, which breaks down clots and further contributes to bleeding risk
• Impaired ability to form normal clots at sites of injury due to the depletion of clotting factors and platelets According to the guidance statement from the SSC of the ISTH 1, management of bleeding in DIC involves supportive care with blood products, such as:
• Platelet transfusion to maintain the platelet count above 50 × 10^9/L in patients with active bleeding
• Transfusion of fresh frozen plasma (15–30 mL/kg) with careful clinical monitoring to decide on dose adjustments
• Use of prothrombin complex concentrates in cases of concerns over volume overload
• Transfusion of cryoprecipitate or fibrinogen concentrate in actively bleeding cases with persistently low fibrinogen values.

From the Research

Causes of Bleeding in DIC

• Disseminated intravascular coagulation (DIC) is a complex condition characterized by widespread activation of the coagulation cascade, resulting in both thrombosis and bleeding 2, 3.
• The underlying conditions, such as infection, cancer, or obstetrical complications, trigger an overactive coagulation response, leading to excessive thrombin generation, platelet and fibrinogen activation, and depletion of clotting factors 2, 3.
• This depletion of clotting factors and platelets creates a paradoxical bleeding tendency, which can manifest as bleeding at the site of the tumor or distant metastases 4, 5, 6.

Mechanism of Bleeding in DIC

• The simultaneous consumption of coagulation factors and platelets during the DIC process leads to a potentially life-threatening hemorrhage 2.
• The exhaustion of platelets and coagulation factors can proceed subclinically, eventually leading to bleeding complications, which may be the first clinical symptom indicating the presence of DIC 4, 5, 6.
• The clinical presentation of DIC in cancer may be reminiscent of thrombotic microangiopathies, which is understandable in view of the role of the endothelium in both conditions 4, 5.

Clinical Implications of Bleeding in DIC

• The therapeutic cornerstone of DIC is treatment of the underlying disorder, but supportive treatment specifically aimed at the hemostatic system may be required 2, 4, 5, 6.
• Diagnosing DIC is challenging and relies on a combination of existing diagnostic criteria and laboratory tests, and recent advances in understanding the pathophysiology of DIC are paving the way for more targeted therapeutic approaches 3.
• Treatment strategies focus on addressing the underlying causes and may involve supportive care, anticoagulation therapy, and other supportive measures to manage the bleeding complications associated with DIC 2, 3, 6.