DISSEMINATED INTRAVASCULAR DISEASE

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Disseminated intravascular coagulation, formerly termed as disseminated intravascular coagulopathy, is not a disease but a sign of an underlying condition. DIC may be triggered by sepsis, trauma, cancer, shock, abruptio placenta, toxins or allergic reactions. The severity of DIC is variable, but it is potentially life-threatening.

PATHOPHYSIOLOGY

 Normal homeostatic mechanism are altered in DIC so that a massive amount of tiny clots forms in the microcirculation. Initially, the coagulation time is normal. However, as the platelets and clotting factors are consumed to form the microthrombi, coagulation fails. Thus, the paradoxical result of excessive clotting is bleeding. The clinical manifestations of DIC are reflected i the organs, which are affected either by excessive clot formation (with resultant ischemia to all or part of the organ) or by bleeding. The excessive clotting triggers the fibrinolytic system to release fibrin degradation products, which are potent anticoagulants, furthering the bleeding. The bleeding is characterized by low platelet  and fibrinogen level; prolonged PT, PTT, and thrombin time; and elevated fibrin degradation products (D-dimers).

Identification of patients who are at risk  for DIC and recognition of the early clinical manifestations of this syndrome can result in earlier medical intervention, which may improve the prognosis. However, the primary prognosis factor is the ability to treat the underlying condition that precipitated DIC.

CLINICAL MANIFESTATIONS

Patients with frank DIC may bleed from mucous membranes, venipuncture sites, and the GI and urinary tracts. The bleeding can range from minimal occult internal bleeding to profuse hemorrhage from all orifices.  The patient may also develop organ dysfunction, such as renal failure and pulmonary and multifocal central nervous system infarctions, as a result of microthromboses, macrothromboses, or hemorrhages. During the initial process of DIC, the patient may have no new symptoms, the only manifestations being  a progressive decrease in the platelet count. As the thrombosis becomes more extensive, the patients exhibits signs and symptoms of thrombosis in the organs involved. Then, as the clotting factors and platelets are consumed to form these thrombi, bleeding occurs. Initially the bleeding is subtle, but it can develop into frank hemorrhage.

MEDICAL MANAGEMENT

The most important management factor in DIC is treating the underlying cause ; until the cause is controlled, the DIC will persist. Correcting the secondary effects of tissue ischemia by improving oxygenation, replacing fluids, correcting electrolyte imbalances, and administering vasopressor medications is also important.  If serious hemorrhage occurs, the depleted coagulation factors and platelets may be replaced to reestablish  the potential for normal hemostasis and thereby diminish bleeding. Cryoprecipitate is given to replace fibrinogen and factors V and VII; fresh frozen plasma is administered to replace other coagulation factors. A controversial treatment strategy is to interrupt the thrombosis process through the use of heparin infusion. Heparin may inhibit the formation of microthrombi and thus permit perfusion of the organs (skin, kidneys or brain) to resume. Heparin use was traditionally reserved   for patients in whom thrombotic manifestations predominated or in whom extensive blood component replacement failed to halt the hemorrhage or increased fibrinogen and other clotting levels. Heparin is now considered also applicable for use in less acute forms of DIC (Leung, 2004). The effectiveness of heparin can best be determined by observing for normalization of the plasma fibrinogen concentration and diminishing  signs of bleeding. Fibrinolytic inhibitors, such as aminocaproic acid (EACA), Amicar), may be used with heparin. Other therapies include recombinant activated protein C (APC; drotrecogin alfa [Xigris]), which is effective in diminishing inflammatory responses on the surface of the vessels as well as having anticoagulant properties (Aird, 2004).  Bleeding is common, can occur at any site, and can be significant. Antithrombin (AT) infusions can also be used for their anticoagulant and anti-inflammatory properties. Bleeding can be significant, particularly when administered in association with heparin.

 

Reference: Suzanne C. Smeltzer, et.al. Brunner & Suddarth’s Textbook of Medical-Surgical Nursing 11th edition Lippincott Williams & Wilkins pp. 1093-1094

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