Introduction and classification of anemia’s
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Transcript of Introduction and classification of anemia’s
OBJECTIVESAt the end of this lecture, one
should know:
1. Simple basics about
erythrocytes
2. Important terminology related
to RBC’s
3. Definition of anemia
4. Clinical features and Signs
and Symptoms
5. Classification of anemia
CONTENTS
Introduction to RBC’s
RBC cell indices and Haemeglobin
Anemia- Definition
Signs and symptoms
Investigations
Pathophysiologic classification
Morphological classification
Introduction To RBC The mature erythrocytes are non-
nucleated cells and lack usual cell organelles.
The normal RBC is biconcave in shape,7.2µm in diameter and has a thickness of 2.4µm at the periphery and 1µm in the center.
The biconcave shape helps the RBC to pass through the smallest capillaries
90% of the RBC’s weight is concentrated in the red pigment hemoglobin and the RBC’s have a lifespan of 120±30 days.
Functions of RBC’s• The most important function of an
RBC is the transportation of oxygen
to tissues with the help of HbA
present in normal adults.
• The 4 units of HbA take up oxygen in
succession which results in stepwise
affinity of hemoglobin for oxygen
and thus is responsible for the
sigmoid shape of the oxygen
dissociation curve
• Another important function of RBC’s
is the transportation of CO2 from the
tissues to the lungs.
Normal Values• Range of normal RBC count is:5.5±1.0
and 4.8±1.0 ×1012/L and the Hemoglobin
content being 15.5±2.5(13-18)g/dl and
14.0±2.5(11.5-16.5)g/dl in Men and
Women respectively.
• The packed cell volume or the
haematocrit is the volume of the
erythrocytesper litre of whole blood is
40-54% and 37-47% in Men and Women
respectively
• Based on these normal values red cell
indices have been devised,which are of
diagnostic importance.
Haemoglobin
• Haemoglobin is a
basic protein,GLOBIN
and of iron-porphyrin
complex HEME with a
molecular weight of
68,000 and consists of
4 polypeptides.
• Normal adult
hemoglobin is-α2β2
which is called HbA
and other forms also
exist such as
HbF(foetal) and HbA2.
ANEMIA• DEFINITION:Anemia is defined as the clinical condition
which is caused by a reduced number of RBC’s or
reduced hemoglobin concentration in the blood
below the lower limit of the normal range for the age
and sex of the individual.
• In Adults the lower value is taken as 13.0g/dl and
11.5g/dl of normal haemoglobin for men and women
respectively.
History of Anemia• The word "anemia" is composed of
two Greek roots that together mean "without blood," but to use this literal translation as a definition would be a gross exaggeration.
• The ancients readily recognized the importance of blood as a life- giving substance, believing it to hold the body's vital force. Hebrews back to the patriarchal age maintained that blood was the seat of the soul and demanded through the Mosaic Laws that it be drained before an animal was prepared as food (a practice still followed by Orthodox Jews today). The Romans drank the blood of their enemies, thinking it would confer on them the courage of their vanquished foes.
Investigations Haemoglobin Estimation
Peripheral blood smear
examination
Red cell indices
Leucocyte and platelet count
Reticulocyte count
Erythrocyte sedimentation
rate
Bone marrow examination
Classification
• Classification of Anemia’s is done in 2 types:
1. Pathophysiological classification
2. Morphological classification
Pathophysiological Classification
1. Anemia due to increased blood loss:a. Acute post-hemorrhagic anemia
b. Anemia of chronic blood loss
2. Anemia due to impaired RBC production:a.Cytoplasmic maturation defects
Eg: Deficient heme synthesis-Iron deficiency Anemia
Deficient Globin synthesis-thalassemia
b.Nuclear maturation defects
Eg:Megaloblastic anemia
c.Hematopoetic stem cell proliferation and
differentiation abnormality
Eg:Aplastic anemia
Pure red cell aplasia
d.Bone marrow Failure due to systemic diseases
Eg: Anemia in renal disease/inflammation
e.Bone marrow infiltration
Eg: Leukemia,Lymphoma etc
f.Congenital anemias
Eg:Sideroblastic anemia
3.Anemia due to increased RBC destruction
a) Intracorpuscular Defects
Eg:Hereditary Spherocytosis
b)Extracorpuscular Defects
Eg:Auto immune hemolytic disorders