Heparin-Induced Thrombocytopenia (HIT)
        Heparin-Induced Thrombocytopenia and Thrombosis Syndrome (HITTS)
        ================================================================
þ HIT:
 - drop in platelets to 50% of baseline, or below 150K
 - in 3% of those treated with heparin, 0.5% of those with enoxaparin
   (LOVENOX)
 - generally 5-14 days after exposure
 - can present with DVT, arterial clot (e.g., MI, limb ischemia, bowel
   ischemia)
 - IgG antibody reaction to heparin: can activate platelets, basically causing
   induced TTP <TTP.TXT>
 - do NOT treat with heparin!
 - consult hematologist

Type I: right after heparin, true allergy, rare

Type II: a week later, come back after discharge, most common.
 Often present with DVT after heparin exposure, or on Lovenox.
 May get local HIT in one area of skin after inserting heparin.
 Get BIG clots. 

Delayed Onset: up to a month later, rare

The four Ts:
Thrombocytopenia
Timing (a week later)
Thrombosis
Third Cause?

Tends not to recur, can get heparin again, at least based on a case series of 7.

DIC: <dic.txt>