Clinical features may be masked by those of the disorder which precipitated it and rarely is the cause of DIC obscure. DIC should be considered in the management of any seriously ill patient. The specific features of DIC are:

• Ecchymoses, petechiae, oozing from venepuncture sites and post-op bleeding. 513

• Renal dysfunction, ARDS, cerebral dysfunction and skin necrosis due to microthrombi.

Laboratory features

The following investigations are useful in establishing the diagnosis of DIC though the extent to which any single test may be abnormal reflects the underlying cause of DIC.

• D-dimers—more specific and convenient than FDP titre (performed on plasma sample). Significant 4 of D-dimers plus depletion of coagulation factors ± platelets is necessary for diagnosis of DIC.

• PT—less sensitive, usually 4 in moderately severe DIC but may be normal in chronic DIC.

• APTR—less useful. May be normal or even <normal, particularly in chronic DIC.

• Fibrinogen—5 or falling fibrinogen levels are characteristic of many causes of DIC in the presence of D-dimers. Greatest falls are seen with tissue factor release.

• Platelet count—5 or falling platelet counts are characteristic of acute DIC, most notably in association with infective causes.

• Blood film may show evidence of fragmentation (schistocytes) though the absence of this finding does not exclude the diagnosis of DIC.

• Antithrombin levels are frequently 5 in DIC and degree of reduction in plasma antithrombin and plasminogen may reflect severity.

• Factor assays rarely necessary or helpful. In severe DIC levels of most factors are reduced with the exception of FVIIIc and von Willebrand factor which may be increased due to release from endothelial cell storage sites.

Management of DIC

1. Identify and, if possible, remove the precipitating cause.

2. Supportive therapy as required (e.g. volume replacement for shock).

3. Replacement therapy if bleeding: platelet transfusion if platelets <50 x 109/L, cryoprecipitate to replace fibrinogen, and FFP to replace other factors (10 units cryoprecipitate for every 3 units FFP).

4. Prophylactic platelet transfusion may be helpful if platelets <20 x 109/L.

5. Monitor response with platelet count, PT, fibrinogen and D-dimers.

6. Heparin (IVI 5—10iu/kg/h) for DIC associated with APML, carcinoma, skin necrosis, purpura fulminans, microthrombosis affecting skin, kidney, bowel and large vessel thrombosis.

7. ATIII concentrate in intractable shock or fulminant hepatic necrosis.

8. Protein C concentrate in acquired purpura fulminans or severe neonatal DIC.

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