Internal Medicine

P1: RLJ/OZN P2: KUF

0521779407-D-01 CUNY1086/Karliner 0 521 77940 7 June 13, 2007 7:41

492 Disseminated Intravascular Coagulation

■Reticulocytes may be assessed on peripheral smear as large bluish

red cells without central clearing; often present in increased numbers

in TTP/HUS.

■Lactate dehydrogenase (LDH) level is generally elevated.

■Creatinine may be elevated in any of these disorders, but elevation

is most prominently a feature of HUS.

■Prothrombin time (PT) and partial thromboplastin time (PTT) are

normal in uncomplicated TTP/HUS; may be elevated in DIC.

■Fibrinogen level is normal in TTP/HUS; low or normal in DIC.

■Fibrin split products are elevated in DIC and normal or only slightly

elevated in TTP/HUS in the absence of liver disease or injury.

Additional Studies

■For DIC: blood cultures if appropriate; consider CT scan to search

for underlying malignancy in chronic DIC

■For suspected HUS: If diarrhea is present send stool for culture; con-

sider HIV test

differential diagnosis

■Since microangiopathic changes may be seen with malignant hyper-

tension or with leaks around mechanical valves, these possibilities

should routinely be excluded when a diagnosis of DIC/TTP/HUS is

being considered.

management

What to Do First

■On the basis of history, symptoms and signs, and basic laboratories,

decide whether DIC or TTP/HUS is present.

■If DIC is suspected, be sure that the elevation in PT/PTT is not spu-

rious (heparin contamination).

General Measures

■Avoid platelet transfusion until the distinction between DIC and

TTP/HUS is established, as it is generally contraindicated in

TTP/HUS.

■Packed red blood cell transfusion may be administered as deemed

appropriate.

specific therapy

DIC

■Define the underlying cause and provide appropriate therapy.

■While treating the underlying cause, decide if blood product support

is indicated: