Sect 4 - Immune Hemolytic Anemia

Immune Hemolytic Anemia

anemias as a result of a shortened RBC lifespan, mediated through the immune response

Alloimmune

Autoimmune

Drug-Induced

3 categories of Immune Hemolytic Anemias

Alloimmune Hemolytic Anemia

caused by blood transfusion reactions

associated with ABO incompatibilities

Immediate Reaction and Delayed Reaction

2 types of Alloimmune Hemolytic Anemia

Immediate Reaction

happens while pt is receiving their transfusion

associated with ABO incompatibilities

Clinical Features of Immediate Alloimmune Hemolytic Anemia

fever, shaking, and chills

pain at infusion site

nausea and vomiting

lower back pain (kidney/liver overworked)

hypotension

hemoglobinemia/hemoglobinuria

intravascular hemolysis

can lead to DIC

Lab Features of Immediate Alloimmune Hemolytic Anemia

increased plasma free hgb

decreased haptoglobin lvls

increased bilirubin

may see schistocytes on PBS

Delayed Reaction

results from a secondary response to transfused RBC antigens; occurs in a previously sensitized patient

can happen days after transfusion was received

Clinical Features of Delayed Alloimmune Hemolytic Anemia

fever

anemia

mild jaundice

extravascular hemolysis

Lab Features of Delayed Alloimmune Hemolytic Anemia

decrease in hgb

increased bilirubin

increased fecal & urine urobilinogen

positive DAT

Spherocytes on PBS

Hemolytic Disease of the Newborn

disorder where RBC of fetus/newborn are destroyed by maternal IgG antibodies that cross the placenta

can be ABO or Rh incompatible

Clinical Features of ABO-HDN

usually happen when group O mom gives birth to group A / B baby

mild jaundice

Lab Features of ABO-HDN

negative to moderately positive DAT (1+, 2+)

numerous spherocytes

increased bilirubin

Treatment of ABO-HDN

phototherapy if needed to break down bilirubin

Rh-HDN

primary sensitization of Rh-neg mom with Rh-pos blood either through a previous pregnancy, blood transfusion or abortion

first pregnancy: expressed (mom starts making anti-D)

secondary pregnancy: anti-D present

Clinical Features of Rh-HDN

jaundice

anemia

hepatosplenomegaly

erythroblastosis fetalis (stillborn)

kernicterus

congestive heart failure

Lab Features of Rh-HDN

mild to severe anemia (hgb 8-13 g/dl)

increased retic count

increased WBC

increased NRBCs

positive DAT

positive anti-D antibody in mother's serum

increased in unconjugated bilirubin in baby

Treatment of Rh-HDN

intrauterine transfusions

maternal plasmapheresis

exchange transfusion

phototherapy

Rhogam

Prevention of Rh-HDN

a passive form of anti-D given during pregnancy or after delivery

Autoimmune Hemolytic Anemia

the body's inability to recognize "self" antigens

autoantibodies bind to pts own RBCs causing hemolysis

Warm Autoimmune Hemolytic Anemia (WAIHA) and Cold Autoimmune Hemolytic Anemia (CAIHA)

2 types of Autoimmune Hemolytic Anemia

Warm Autoimmune Hemolytic Anemia

What does WIAHA stand for?

WAIHA

autoantibodies whose optimum serological reactivity is 37C (body temp) (IgG)

extravascular hemolysis (destroyed in liver/spleen)

autoimmune disorder

WAIHA usually associated with

ex: Crohn's, Rheumatoid Arthritis, Lupus, Ulcerative Colitis

Clinical Features of WAIHA

pallor, weakness, dizziness

dyspnea (shortness of breath)

jaundice

fever

hemoglobinuria

hemoglobinemia

Lab Features of WAIHA

decreased hgb (7 g/dl)

increased retic count

increased bilirubin and urobilinogen

decreased serum haptoglobin

increased lactate dehydrogenase

positive DAT

Morphology seen in WAIHA

polychromasia, spherocytes, schistocytes

Treatment for WAIHA

treat underlying disease

transfusions with blood without antibodies

corticosteroids

splenectomy

immunosuppressive drugs

Cold Autoimmune Hemolytic Anemia

What does CAIHA stand for?

CAIHA

autoantibodies whose optimal serological reactivity occurs at 4C and between 25-31C (IgM)

Cold agglutinin syndrome

Secondary CAIHA

PCH

3 types of CAIHA

Cold Agglutinin Syndrom

rare, severe, seasonal disease

winter months precipitate S/S of the disease

peak age onset is 50years old

anti-I

What antibody is almost always involved in Cold Agglutinin Syndrome

Clinical Features of Cold Agglutinin Syndrome

acrocyanosis of hands, feet, ears, and nose

numbness of extremities

hemoglobinuria

weakness and pallor

weright loss

jaundice

Lab Features of Cold Agglutinin Syndrome

increased retic count

autoagglutination at 20C

positive DAT

Hgb and HCT do NOT match

macro (MCV)

decreased RBC

polychromasia, anisocytosis, and poikilocytosis

Secondary CAIHA

cold autoantibodies produced, which are secondary to infections, usually respiratory infections

Clinical Features of Secondary CAIHA

pallor

jaundice

splenomegaly

anemia

Lab Features of Secondary CAIHA

same as in cold agglutinin syndrome

increased retic count

autoagglutination at 20C

positive DAT

Hgb and HCT do NOT match

macro (MCV)

decreased RBC

polychromasia, anisocytosis, and poikilocytosis

Treatment for both Cold Agglutinin Syndrome & Secondary CAIHA

move to warmer climate

Paroxysmal Cold Hemolglobinuria

What does PCH stand for?

viral disease

PCH is found most often in children in association with

**less common due to vaccines

Donath-Landsteiner antibody (IgG)

What antibody is associated with PCH?

PCH

Donath-Landsteiner ab (IgG) - normally warm but reacts when cold

antibody binds at cold temps, and causes lysis when pts body returns to normal body temp

does not cause hemolysis until pt warms up from cold temps

Clinical Features of PCH

fever, shaking and chills

malaise

abdominal cramps

back pain

hemoglobinuria/hemoglobinemia

splenomegaly

renal insufficiency (verge of shutting down)

Lab Features of PCH

decreased Hgb (4-5 g/dl)

Donath-Landsteiner ab: positive

polychromasia, NRBCs, poikilycotosis

Treatment of PCH

protection from cold exposure

Drug-Induced Hemolytic Anemia

hemolytic anemias induced by taking certain drugs

Immune complex

Drug adsorption

Autoantibody formation

Non-specific protein adsorption

4 mechanisms of Drug-Induced Hemolytic Anemia

Immune Complex Mechanism

drug induced hemolytic anemia where the drug binds to plasma proteins and antibodies are made against the drug and directly activates complement

most common drugs: Quinidine and Sulfonamides

Clinical and Lab Features of Immune Complex Mechanism

intravascular hemolysis

hemoglobinuria/hemoglobinemia

positive DAT

in vitro agglutination when pts serum (ab) + pts RBC (ag) + drug are incubated together

Drug Adsorption Mechanism

drug is adsorbed on to red cell and induces an immune response

most common drugs: penicillin, streptomycin, cephalosporin

Clinical and Lab Features of Drug Adsorption Mechanism

extravascular hemolysis

positive DAT

Autoantibody Formation Mechanism

drug interacts with T-regulatory cells, causing them to become dysfunctional and tell B-cell lymphs to produce abnormal B-cells

most common drugs: Aldomet, Other alpha-methyl dopa drugs

Clinical and Lab Features of Autoantibody Formation Mechanism

extravascular hemolysis

positive DAT

warm autoantibody production

Non-specific Protein Adsorption

proteins (complement, immunoglobulins, albumin, and fibrinogen) are absorbed onto the RBC membrane

most common drugs: Cephalosporins

causes a positive DAT and difficulty when crossmatching blood