Other hemolytic anemias Flashcards
(44 cards)
Defects in RBC membrane
Cation permeability
Hereditary Stomacytosis
Hereditary Xerocytosis
Defects in RBC membrane
Cytoskeleton
Herditary Spherocytosis
Hereditary Elliptocytosis
Hereditary Pyropoikolocytosis
Hereditary spherocytosis
- Most common
- Spectrin deficiency (cytoskeleton)
- Problem: Loss of surface area - decreased surface to volume ratio
- Clinical manifestations
1. splenomegaly
2. Jaundice
3. Anemia
Hereditary Spherocytosis
LAB
- Decreased Haptoglobin
- Normal or increased MCHC
- Increased osmotic fragility
- Increased reticuolcytes
- Increased bilirubin (indirect and total)
Hereditary spherocytosis
Morphology + treatment?
Morphology - spherocytes
Treatment - Total or Partial splenecotomy
Cause of hereditary elliptocytosis
defective or deficienct spectrin (cytoskeleton)
- Weakened cytoskeleton cannot go back to original form after shear stress
Clinical subtypes of Elliptocytois
- Common Hereditary Elliptocytosis
- Southeast Asian Ovalocytosis
- Spherocytic Hereditary Elliptocytosis
- Hereitary Pyropoikilocytosis
Hereditary elliptocytosis
severity + Morphology?
Severity - anemia severity varies from asymptomatic to severe between types.
Morphology - Elliptocytes, some HE clinical subtypes exhibit ovalocytes
Hereditary Pyropoikilocytosis
Cause?
Problem?
RARE
Cause - Reduced assembly of spectrin + increased spectrin degradation
Problem - Severely weakened cytoskeleton that cannot go back to original form and may fragment after shear stress.
Hereditary pyropoikilocytosis
symptoms
- severe hemolysis
- Poor growth
- Bone expansion - facial abnormalities
morphology of pyropoikilocytosis
Schistocytes !
Other fragmented cells, spherocytes, elliptocytes, bizarre RBCs
RBCs heat sensitive and can fragment at body temperature (pyro)
Hereditary Stomacytosis (permeability)
Cause?
Problem?
Cause - Deficiency in stomatin - a protein that regulates ion transport across RBC membrane
Problem?
- increased permability to sodium (Na+)
- Na+ influxes into cell
- Water follows and influxes into cell
Hereditary Stomacytosis - Lab findings
High MCV
Low MCHC
Morphology: stomatocytes
Treatment: Splenectomy
Hereditary Xerocytosis
Cause?
Problem?
Cause - unknown, but due to defect in membrane permeability
Problem
- Increased permeability to Potassium (K+)
- K + OUTfluxes from cell
- Water follows outfluxing
- Results in cell dehydration with hemoglobin concentrating in one area
Herditary Xerocytosis Lab findings
High MCHC
Low Osmotic Fragility - more resistant
morphology - Target cells, crenated cells and Xerocytes
Hexose monophosphate pathway
G6PD deficiency
Glycolytic pathway
Pyruvate Kinase Deficiency
Methemoglobin Reductase Pathway
Methemoglobin reductase deficiency
Hexose monophosphate pathway aka phosphogluconate pathway /PPP
- Uses 5-10% of RBC glucose
- Forms NADPH
- NADPH is reduced and forms reduced Glutathionene (GSH)
- GSH protects hemoglobin from oxidative denaturation
G6PD Deficiency
X linked recessive disorder (more prevalent in males)
- Decrease in G6PD
Hgb becomes susceptible to oxidation, followed by denaturation and precipitation
- increased Heinz bodies
In G6PD deficiency ..heinz bodies are
Removed in the spleen, leaving (helmet cells) aka. bite cells
G6PD deficiency, RBC loses deformability ..
tough time getting through microvasculature
- leads to premature destruction in the circulation = intravascular hemolysis
G6PD clinical manifestiations
Majority is asymptomatic
- only 20% of normal G6PD activity is required for normal RBC function
Clinical manifestations occur in states of oxidation:
1. oxidative drugs
2. Infections
3. Ingestion of fava beans
G6PD - Favism
Fava beans contain chemicals that destroy gluthione
Always want to pair with a nice Chianti
