Nejm 1999;341:586

Cause:

2 requirements: 1) reticuloendothelial system blockade by pregnancy, endotoxin, radiation, steroids, colloid, and 2) clotting system activated by:

• Thromboplastin releaser, eg, frozen tissue, placenta, tumors, trypsin, snake venom (Nejm 2010;362:2212), open brain trauma (Nejm 1974;290:1043), renal transplant rejection (Nejm 1970;283:383); or
• Defibrination agent, eg, amniotic fluid; or
• Platelet factor 3 (phospholipid) release, eg, platelet clot, hemolysis, fat embolism, immune reaction; or
• Activation of factor XII, eg, by exo- or endotoxin from sepsis

Pathophys:Fibrinogen is low due to consumption and rapid lysis; tissue damage esp in CNS, lung, and kidneys from thrombotic ischemia

More common than TTP. Increased incidence in OB esp with septic abortions, abruptio, eclampsia, mole, amniotic fluid embolus, missed abortion, retained dead fetus, fatty liver of pregnancy (Ann IM 1983;98:330); leukemias, cancers, and all cases of severe tissue damage; freshwater drownings; gram-negative sepsis

Sx:Bleeding, coma; fever only if there is a secondary cause of fever, unlike TTP

Si:Palpable purpuric rash (r/o allergic vasculitis); shock, hypotension; oozing/bleeding at all sites

Acute, hours to days

Renal cortical necrosis, ATN, Sheehan's syndrome, acute cor pulmonale, adrenal insufficiency (rarely fatal)

r/o other microangiopathic anemias: TTP, HELP, HUS, malignant HT, and chemoRx-induced types

Lab:

Hem: Smear shows microangiopathic anemia with helmets and other fragments. Platelets <100 000. ESR = 0 (afibrinogenemia). PT, very sensitive (R. Hillman 3/86), and PTT prolonged. Fibrinogen <40 mg %; low levels of II (hence PT long), VIII, V (<50% is diagnostic). Fibrin split products (D-dimers) markedly elevated; prolonged thrombin time. Elevated antithrombin III (Hillman 3/86)

Urine:Hematuria, isosmolar anuria late when ATN develops

Rx:Treat primary problem; replace factors, eg, fresh-frozen plasma and platelets; perhaps heparinize at low doses like 300-400 U/h or w LMW heparin, possibly antithrombin III, to break the consumption cycle; never do so in face of liver disease, and only as a last resort if chronic cause and uncontrollable bleeding

Of snake bite: antivenom repeatedly to reverse DIC