Internal Medicine

0521779407-10 CUNY1086/Karliner 0 521 77940 7 June 6, 2007 17:44

Intravascular, Non-immune Hemolytic Anemia 863

Chemical/Venom

■strong oxidant or proteolytic activity (venom) overwhelm normal

reduction mechanisms or physical barriers responsible for protect-

ing the integrity of the red blood cell

■often a metabolite of the chemical/drug is responsible

■fetal/newborn red cells have immature reduction pathways and thus

are more sensitive to oxidant activity

■nitrofurantoin, sulfasalazine, p-Aminosalicylic acid, phenazopyri-

dine, phenacetin, paraquat, naphthalene, isobutyl nitrate, amyl

nitrite, dapsone, heavy metals (copper, lead, arsenic), cobra venom,

brown recluse spider venom

Thermal

■normal red cells undergo lysis when heated to temperatures >49

degrees Celsius

■seen in patients transfused with faulty blood warmers and patients

who have experienced extensive burns

Mechanical

■faulty natural valves or foreign material is placed within the vascu-

lature (e.g., artificial valvular prostheses, stents, coils, TIPS, shunts,

cardiopulmonary bypass)

■fibrin strands and/or platelet thrombi obstruct small blood vessels

(microangiopathic hemolytic anemias – DIC, TTP, HUS)

■direct physical force compresses superficial blood vessels (e.g.,

marching, jogging, karate, conga drummers)

management

What to Do First/General Measures

■DIC

■identify and correct underlying etiology; supportive care

■TTP

■initiate plasma exchange with fresh frozen plasma, steroids, and sup-

portive care

■HUS

■supportive care and initiate dialysis for acute renal failure

specific therapy

Indications

■DIC

■bleeding, thrombosis, anemia