Hemolytic Anemias 2

Question 1

Extravascular vs Intracascular Hemolysis

Answer 1

Ex: defective and deformed RBCs are removed by the spleen
In: RBCs are damaged/destroyed while in circulation, haptoglobin binds to free hemoglobin to prevent the oxidizin effects of free hemoglobin

Question 2

Autoimmune Hemolytic Anemia (AIHA)

Answer 2

Caused by antibodies produced by the body that bind to antigens on RBCs
Can be warm or cold

Question 3

Warm AIHA

Answer 3

Antibodies that bind to RBCs and cause RBC lysis at body temperature (37C)
Usually IgG antibodies
Against Rh system (D, C, E)

Question 4

WAIHA Labs

Answer 4

Decreased RBC, Hgb, Hct, Haptoglobin
Increased RDW, Retic
Normal MCV, MCHC
Positive DAT

Question 5

WAIHA Microscopics

Answer 5

Polychromasia, spherocytes, micro-spherocytes

Question 6

Cold AIHA

Answer 6

Antibodies that bind to RBCs and activate complement at temperatures lower than body temp
Usually IgM antibodies
AKA Cold agglutinin syndrome
Idiopathic: IgM against I antigen
Secondary: due to mycoplasma = IgM against I antigen, due to infectious mono = IgM against i antigen

Question 7

CAIHA Labs

Answer 7

Falsely decreased RBC, Hct
Falsely increased MCV, MCH, MCHC
Get accurate results by pre-warming 
Decreased RBC, Hgb, Hct, Haptoglobin 
Increased Retic
Normal MCV, MCH, MCHC
DAT negative with anti-IgG, positive with polyspecific AHG

Question 8

CAIHA Microscopics

Answer 8

Polychromasia, spherocytes, possible NRBCs

Question 9

Hemolytic Transfusion Rxn

Answer 9

Immediate: usually ABO incompatibility, but also happens with other blood groups
Delayed: associated with antibodies to Kidd antigens (Jka, Jkb)

Question 10

HTR Labs

Answer 10

Variable CBC
Variable DAT based on hemolysis
Decreased haptoglobin

Question 11

Hemolytic Disease of the Fetus and Newborn (HDFN)

Answer 11

Caused by Rh incompatibility between mother and fetus
Causes hemolysis in the fetus and can lead to anemia and intramedullary hematopoiesis
Quantified by Kleihauer Betke Test or by flow cytometry for fetal hemoglobin

Question 12

HDFN Labs

Answer 12

Decreased Hgb, Hct
Increased Retic
Normal MCV (newborn RBCs are large)

Question 13

HDFN Microscopics

Answer 13

Polychromasia, numerous NRBCs, possible poikilocytosis

Question 14

Microangiopathic Hemolytic Anemia (MAHA)

Answer 14

Group of disorders that are caused by microcirculatory lesions
Fibrin strands in the microcirculation activate platelets and cleave RBCs
Cause thrombocytopenia and hemolysis

Question 15

MAHA Labs

Answer 15

Decreased Hgb, Hct, Plt

Increased WBC, RDW, Retic

Question 16

MAHA Microscopics

Answer 16

Schistocytes, thrombocytopenia, anemia, polychromasia, possible NRBCs, possible left shift

Question 17

Hemolytic Uremic Syndrome (HUS)

Answer 17

Associated with acute renal failure
Divided into HUS with or without diarrhea
Caused by infectious damage to the capillaries of the glomerulus by E coli/Shigella

Question 18

Thrombotic Thrombocytopenia (TTP)

Answer 18

Caused by ADAMTS13 deficiency or autoantibodies against ADAMTS13
ADAMTS13 cleaves vWF which helps prevent excessive platelet aggregation in the circulation

Question 19

DIsseminated Intravascular Coagulation (DIC)

Answer 19

Causes a consumption of clotting factors resulting in severe bleeding complications
HELLP syndrome can lead to DIC

Question 20

HELLP Syndrome

Answer 20

Obstetric complication, severe form of pre-eclampsia
Hemolysis, elevated liver enzymes, low platelet count
Can lead to DIC

Question 21

Traumatic Cardiac Hemolytic Anemia

Answer 21

AKA Waring Blender syndrome
Arises as a complication to the presence of a prosthetic heart valve
Shear stress around the valve causes RBC hemolysis

Question 22

Thermal Injury

Answer 22

RBCs fragment at 48 to 50 C
Causes membrane budding, spherocytes, and schistocytes
Hemoglobinuria lasts for 48 hours after the injury

Question 23

Exercise Induced Hemoglobinuria

Answer 23

Hemoglobinuria appears for a few hours after exercising

CBC and peripheral smear are normal