2. objective
What is spherocytosis
What is normal red cell membrane and
its function
What is pathophysiology of HS
Complication of HS
Diagnosis of HS
Differential diagnosis of HS
3. Hereditary spherocytosis
A genetically determined haemolytic aneamia characterized
by spherical shaped RBC,s
Characteristic appearance, round cells with smaller diameter
Lack of area of central pallor, decrease surface to valume
ratio
4. NORMAL RED CELL DESTRUCTION
RBC completes 120 days
Of life span
Changes in cell membrane
occurs
Enzyme activity declines
Effete cells less deformable than normal
Recognized by macrophages
Phagocytosis and cell death
5. Red cell membrane
The red cell membrane consists of:
Proteins 50%
Lipids 40%
Carbohydrates: 10%
6. Functions of red cell membrane
Erythrocyte membrane that is normal in structure and
function is essential to survival of red cell
Maintains stability and normal discoid shape of cell
Preserve cell deformability
Retain selective permeability
8. INTERACTIONS OF RBC MEMBRANE
PROTEIN AND LIPIDS
VERTICAL INTERACTIONS
Perpendicular to cell membrane .
Includes interactions between skeletal lattice on cytoplasmic
side to integral proteins and lipids of membrane
It stabilizes lipid bilayer defects lead to uncoupling of lipid
bilayer from underlying skeleton thus selective loss lipid layer
microvesicle formed
Proteins include: Ankirin, Band 3 ,Glycoporin and Protein 4.2
etc
9. HORIZONTAL INTERACTIONS
Parallel to plane of cell membrane includes spectrin head
to head attachments and protein interaction at junction
complexes
Disruption in these interactions lead to destabilization of
membrane poikilocyte
e.g.
Spectrin
Actin
10. EPIDEMOLOGY
o Most common inherited membran disorder
o 75% autosomal dominant fashion
o 25% Rarely autosomal recessive
15. Form of HS on the bases of Severity
Mild HS
20 to 30 percent have of cases. These p
No anemia,
Little splenomegaly or jaundice,.
Normal hemoglobin levels
16. Moderate HS
60 to 75 percent of cases.
Moderate anemia
Have high reticulocyte counts,
Elevated serum bilirubin concentrations.
splenomegaly mild to moderate
17. Severe HS
5 percent
marked hemolysis and marked anemia,
hyperbilirubinemia, 17-70 micro mole/L
Marked splenomegaly
Gall bladder stones
The pattern of inheritance is almost always recessive and
the parents of an affected patient are usually
asymptomatic.
18. Diagnosis
BLOOD PICTURE
Hb = 7-14g /dl
May fall below 7 in crises
May be normal in compensated hemolysis MCV =N or
slightly reduced
MCH= Normal
Mchc= Increased
Plt = normal or decreased
19. Peripheral smear
ANISOCYTOSIS
Spherocyte
POIKILOCYTOSIS
Polychromatic cells
Target cells
Nucleated RBC can be present severe cases
Plt decreased if splenomegaly
Retic Usually 5-20%
Sometimes 50-70%
22. Osmotic fragility test
Principle
When an erythrocyte is placed in a hypotonic sodium
chloride-(NaCl) solution, a net influx of solvent (water) into
the cell-will occur and the cell will swell.
If the cell size reaches a certain point, the cell membrane will
become leaky and hemoglobin will diffuse out (hemolysis).
If the NaCl solutions hypotonic enough, the cell will rupture.
The degree of hemolysis can be measured by determining the
absorbance of the supernatant using a spectrophotometer.
23.
24.
25. Red cell membrane detection
Red cell membrane can be detected by SDS
-PAGE
26. Summary
Genitic disorder of red cell membran
Mainly due to ankirin deficiency
Extravascular hemolysis
Severity depend on mutation in gene
Diagnosis on osmotic fragility test and
PAGE. SDS
