Hematology: Extracorpuscular defects

Microangiopathic hemolytic anemia

damage to small vessel walls

MAHA mechanism of hemolysis

fibrin forms and shreds RBC

RBC morphology in MAHA

schistocytes and keratocytes

TTP forms what large blockage

von willebrand factor

TTP is caused by what deficiency

ADAMTS-13

What does ADAMTS-13 do

break down VWF into smaller forms (prevents block)

What severe symptoms are seen in TTP

CNS symptoms

TTP RBC morphology

abundant schistocytes

TTP wbc count

left shift, thrombocytosis

HUS difference from TTP

acute renal failure, no CNS symptoms

HUS forms

over active alternative complement
shiga-toxin

HUS shiga toxin target

renal capillary endothelium

HUS urinalysis

increased protein

DIC

RBC fragments from fibrin strands

DIC platelet counts

decreased

DIC has an increase in what markers

FDP and D dimer

TCH

cardiac hemolytic anemia

March hemoglobinuria

exercise induced (feet)

Hemolytic anemia caused by infection

parasites go to spleen and get lysed

Extracellular organisms in hemolytic anemia

clostridium, bartonella

Hemolytic anemia caused by chemicals and drugs

oxidative stress on RBC denatures globin chains and oxidizes heme groups

Hemolytic anemia caused by venom

either directly cause lysis or activate complement

hemolytic anemia caused by thermal injury smear

globular fragments, BUDDING, microspherocytes

Hemolytic anemia caused by thermal injury osmotic fragility

increased

Immune hemolytic anemia

think blood bank (warm/cold Ab, transfusion)

Most common site of immune hemolytic anemia

extravascular

complement mediate hemolysis

C9 (MAC) lyses RBC

Complement hemolysis measured by what

DAT

What immunoglobulin is most likely to activate complement

IgM

IgG mediated hemolysis mechanism

IgG attaches to RBC, Fc receptors on MO bind to IgG in spleen

Cold autoimmune hemolysis immunoglobulin

IgM (I'm cold)

Immediate hemolytic transfusion reactions are caused by

ABO incompatibility

Immediate hemolytic transfusion reactions occur where

intravascular

Delayed hemolytic transfusion reactions occur where

extravascular

Key symptom in HDN

erythroblastosis fetalis

Drug induced Hemolysis

drug binds to RBC, Ab reacts to drug

Non-immune drug induced hemolysis

drug alters RBC membrane