Hemolytic Anemia 1 (CMPP)

Hemolytic Anemia

A condition in which RBC prematurely breakown

In reticulocytosis, what should always be considered as a cause?

Hemolytic Anemias

What characteristics do we classify hemolytic anemias by

Cause of Hemolysis

Location of Hemolysis

Intracorpuscular Hemolytic Anemia

A type of hemolytic anemia caused by a defect within the RBC

Extracorpuscular Hemolytic Anemia

A type of hemolytic anemia where external forces acting on the RBC cause it hemolyse

How do causes of intracorpusclar and extracorpuscular hemolysis causes differ

Intracorpusclar is usually a genetic disorder

Extracorpusclar tends to be an acquired condition

What are common intracorpuscular causes of hemolysis

Enzyme Deficiency (G6PD)

Hgb Defect (Sickle Cell / Alpha and Beta Thalassemia)

Membrane Defect (Hereditary Spherocytosis / Paroxysmal Nocturnal Hemoglobinuria)

What are some extracapsular causes of hemolysis

Mechanical injury

Immunologic

Infection

Meds

Stasis

Intravascular Hemolysis

Hemolysis that occurs within circulation

Haptoglobi

A protein produced by the liver that removes free Hgb from circulation

How does serum haptoglobin levels relate to hemolysis

Low or Absent Haptoglobin = Intravascular Hemolysis

Normal Haptoglobin = Extravascular Hemolysis

If haptoglobin is overwhelmed, how does the body try to remove excess Hgb

Renal filteration

Hemoglobinuria

The presence of Hgb in urine

Sign of intravascular hemolysis

How can we differ hemoglobinuria from hemtauria

If centrifuged, hemtauria will separate into blood and urine while hemoglobinuria will remain stained

How does labs appear with intravascular hemolysis anemias

Hgb/HCT = Low

Reticulocyte = High

Unconjugated Bili = Elevated

Haptoglobin = Absent

Hemoglobinemia / Uria = Present

LDH = high

Bili Urine = Present

Splenomegaly = Absent

Extravascular Hemolysis

Hemolysis that takes place in the macrophage

How will labs appear with extravascular hemolysis anemias

Hg/HCT = Low

Reticulocyte = High

Unconjugated Bili = Very High

Haptoglobin = Low

Hemoglobinemia / Uria = Absent

LDH = High

Bili Urine = Present

Splenomegaly = Present

Direct Coombs test

A test that determines if Ab are attached to the surface of RBC

What are the steps of a direct Coombs test

Blood Draw

Add Coombs Reagent (Anti-IgG + Anti-Complement)

Monitor for Agglutination of Blood (+ Test)

What hemolysis types can be seen with Direct Coombs

Autoimmunity

Alloimmunity (Hemolytic Disease of the New born / Transfusion Reaction)

Drug Induced Hemolysis

What is the most common enzymatic disorder of RBCs

G6PD Deficiency

G6PD Deficiency

A recessive X-lined genetic defect that results in decreased production of G6PD causing extravascular and intravascular hemolysis

What areas have higher incidence of G6PD Deficiency

Malaria Endemic Areas

G6Pd

A normal enzyme in RBCs that protects the cell from oxidative stress by converting NADP+ to NADPH

Free Radicals

Molecules with oxygen ion

Oxidative Stress

Refers to damage caused by the interaction with free radicals

How does oxidative stress affect RBCs

Hgb gets oxidized into methemoglobin and then denatures into insoluble masses, making the cell rigid and prone to destruction

What are signs of excess oxidative stress / G6PD Deficiency on blood smears

Heinz Bodies

Bite Cells

What causes a Heinz body to turn into a bite cell

Macrophages recognizes the Heinz body and removes a portion of the RBC

What are the causes of oxidative stress

Infection (#1)

Medications

Fava Beans

Chemical Exposure

Favaism

An intravascular hemolysis caused in children with low G6PD deficiency by eating to many fava beans

What chemicals can cause oxidative stres

Henna

Naphthalene

Isobutyl Nitrate

Without triggers, how does G6PD Deficiency present

Asymptomatic

With triggers, how does G6PD deficiency present

Jaundice / Icterus

Pallor

Dark Urie

Hyperbilirubinemia

Abdomen/Back Pain

How will G6PD deficient appear on labs

Hgb (Abrupt drop about 3-4) = Low

Reticulocyte = High (Most evident 7-10 days)

Unconjugated Bili = Elevated

Haptoglobin = Low – Absent

Hemoglobinemia / Uria = +/-

LDH = High

Bilirubin Urine = Present

What will appear on a blood smear of G6PD deficiency

Heinz Body and Bite Cells

What patient education do we give to G6PD deficent

Avoid trigger for oxidative stress

Prophylactic Folic Acid should be taken

Remove trigger

Once triggers are removed, when will hemolysis secondary to G6PD deficient resolve

8-14 days

Hereditary Spherocytosis

A rare autosomal dominant defect in the RBC cytoskeleton and cell membrane

What is the most common cause of RBC membrane defect anemias

Hereditary Spherocytosis

What proteins make up RBC cytoskeleton

Band 3 protein

Ankyrin protein

Helix of Spectrin (Alpha and Beta)

Actin-Tropomyosin Complex

How does spherocytosis effect the RBC

Weakens the membrane, allowing K+ and H2O to leave the cell

Causes blebs to form on the RBC

Results in a rounded RBC with no central pallor

What location type of hemolysis occurs with spherocytosis

Extravascular (Splenic Sinusoids) and Intravascular (Oxidative and Acidic Stress)

What complications result from spherocytosis

Can lead to nutrient deficiency that worsen anemia

Anemia can worsen during pregnancy

Can cause a aplastic crisis with infections

Splenomegaly can cause increased pooling/hemolysis

What infection most commonly causes aplastic crisis in patients with spherocytosis

Parovirus B19

What infections can cause increased hemolysis with spherocytosis due to splenic pooling

EBV

Hepatitis

How does hereditary spherocytosis presetn

Splenomegaly

Jaundice

Hyperbilirubinemia

Hemoglobinuria/Emia

Cholelithiasis

Pigmented Gallstones

Gallstones that are made from unconjugated and Ca that appear on XR

Sign of hereditary spherocytosis

How does labs of hereditary spherocytosis appear

Hgb = Low

RDW = High

MCHC = High (Hyperchromic)

MCV = Low (Microcytic)

Bili =High

Haptoglobin = Low

LDH = High

Potassium = Normal to Hight

Coombs = Negative

Smear = Spherocytes

Pseudohyperkalemia

A state of high potassium due to intravascular hemolysis

Eosin-5’-maleimide (EMA) Binding Test

A test where fluorescent dye is added to RBCs to bind to Band 3 protein

Reduced EMA binding = Band 3 defect = Hereditary Spherocytosis

What is test of choice for dx hereditary spherocytosis

EMA Binding Test

Osmotic Fragility

The old test to dx spherocytosis by testing the tonicity response of RBC in hypotonic solution

A positive test occurred when RBC busted and Hgb were detectable

Why is EMA Binding preferred over osmotic fragility

Osmotic Fragility produced more false negatives

What are possible care options for hereditary spherocytosis

Folic Acid Supplementation

EPO to Reduce Transfusion need

Splenectomy

Cholecystectomy

When do we give EPO for hereditary spherocytosis

In children, often discontinued by 9 months of age

When do we splenectomy for hereditary spherocytosis

Severe Cases

Patient > 6 years of Age

When do we perform cholecystectomy for spherocytosis

Presence of Pigmented Gallstones

What vaccines must be given for splenectomy

Pneumococcal

H. flu B

MenA and MenB

Annual seasonal flu

COVID-19

Paroxysmal Noctural Hemoglobinuria

A rare acquired chronic hemolytic anemia where defective myeloid stem cells leads to recurrent nocturnal episodic intravascular hemolysis

When does paroxysmal nocturnal hemoglobinuria present?

3rd to 4th decade of life

What conditions are associated with paroxysmal nocturnal hemoglobinuria

Aplastic Anemia

IDA
Myeloid Leukemia / Myelodysplasia

PIG-A Gene

A gene that codes for the production of RBC membrane proteins CD55 and CD59, which prevents inappropriate complement activation

Mutation leads to deficiency, causing paroxysmal nocturnal hemoglobinuria

How does paroxysmal nocturnal hemoglobinuria present

Fatigue

Dyspnea

Hemoglobinuria

Abdominal / Muscular Pains

Thrombosis (Peripheral / Abdominal / Cerebral Veins)

What causes muscular pains with paroxysmal nocturnal hemoglobinuria

Depletion of NO and Vasospasm

How do labs appear for paroxysmal nocturnal hemoglobinuria appear

hgb/HCT= Low

WBC and PTL = Low

MCV = Normal

Reticulocyte = High

Unconjugated Bili = Elevated

Haptoglobin = Low to Absent

Hemoglobinemia / Uria = Present

LDH = High

Bili Urine = Present

Direct Coombs = Negative

D-Dimer = Elevated

What is needed to dx paroxysmal nocturnal hemoglobinuria

Flow Cytometry

What is the main treatment for paroxysmal nocturnal hemoglobinuria

C5 complement inhibtors

What is the preferred agent for paroxysmal nocturnal hemoglobinuria

Ravulizumab (Ultomiris)

Ravulizumab (Ultomiris)

C5 complement inhibitor

•Eculizumab (Soliris)

C5 complement inhibitor

•Crovalimab (Piasky)

C5 complement inhibitor

What are the benefits to treating paroxysmal nocturnal hemoglobinuria with C5 inhibtors

Relieves symptoms

Reduces transfusion need

What are the downsides to treating paroxysmal nocturnal hemoglobinuria with C5 inhibtors

Duration Unknown

Expensive

Doesn’t prevent failure of bone marrow

Increases risk of N. meningitidis

What should be given prior to starting a patient on C5 inhibtors

Meningococcal Vaccines

Pen V

Due to thrombosis, what should paroxysmal nocturnal hemoglobinuria patients get

Anticoagulant