Disseminated Intravascular Coagulation

The mere mention of the words "the patient has DIC" usually strikes fear into the hearts of attending physicians, laboratorians, and nursing staff. The acute DIC event is almost always unanticipated and dramatic. Fatal outcomes do occur. DIC is triggered by an underlying pathological circumstance occurring in the body (Fig. 18.4). As a result, the hemostatic system becomes unbal anced, hyperactivating the coagulation and/or the fibrinolytic system. This process is systemic, leading to excessive disposition of thrombi or excessive hemorrhage. Additionally, the process is consumptive, consuming clotting factors and platelets as soon as they are activated for coagulation. Usually the decrease in clotting factors is more overpowering than the increase in lysis. In broad terms, DIC is associated with obstetrical complications, malignancy, massive trauma, bacterial sepsis, asplenia, or necrotic tissue. Under each of these major headings are many other pathological possibilities for the initiation of a DIC event (see Table 18.2). Although most DIC occurs as acute, explosive episodes, there are conditions that may lead to a chronic compensated DIC state. These are much more difficult to diagnose because the bone marrow and liver perform an excellent job of maintaining equilibrium between the coagulation and the fibrinolytic system. Laboratory results may be minimally abnormal; yet once the underlying pathology intensifies, an acute DIC episode is likely.9

The Mechanism of Acute Disseminated Intravascular Coagulation

As is customary in normal hemostasis, both the coagulation and the fibrinolytic system are activated in parallel. What is missing in DIC is the negative feedback mechanism that holds the systems in balance. Table 18.2 is a composite of events in the DIC cycle:

Disseminated Intravascular Coagulation
Figure 18.4 Conditions that may precipitate disseminated intravascular coagulation (DIC). Note the multiple pathways. FSPs, fibrin split products.

Table 18.2 O Events Triggering Disseminated Intravascular Coagulation

Infections Gastrointestinal disorders

Table 18.2 O Events Triggering Disseminated Intravascular Coagulation

Infections Gastrointestinal disorders

Gram-negative bacteria

Acute hepatitis

Gram-positive bacteria

Obstetrical complications


Maternal toxemia

Tissue Injury

Abruptio placentae

Crush injury

Hemolytic disease of the


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