Anemia and
Polycythemia
Learning Objectives
At the end of the session you must be able to :
Define anaemia and describe the WHO grading of anaemia.
Describe and discuss morphological and etiological classification of anaemia
Describe the physiological effect of anaemia
Define polycythaemia and describe it’s
classification
Anemia
Definition
Anemia is defined as a decreased O2
carrying capacity of blood due to quantitative
and qualitative Reduction in RBC counts and
Hemoglobin levels.
Anemia
The name is derived from Ancient Greek:
ἀναιμία anaimia, meaning "lack of blood", from ἀν- an-, "not" and αἷμα haima, "blood“
Anaemia is labelled when Hb is less than
13 gm/dl in Males
12 gm/dl in Females
15 gm/dl in Newborn.
The hand of a person with severe anemia (on the left) compared to one without (on the
right)
WHO grading of Anemia
Population Hemoglobin level (gm/dl) Mild Moderate Severe
Women
(15 years of age
and above) 11.9 - 11 10.9 - 8 lower than 8 Men(15 years of age
and above) 12.9 - 11 10.9 - 8 Lower than 8
Classification of Anemia
Morphological Classification
Etiological Classification
Classification of Anemia
Anemia
Morphological
(based on shape and colour)
Etiological
(based on cause)
Macrocytic Anemia Microcytic hypochromic
Anemia
Normochromic normocytic
Anemia Impaired/Defective
RBC production
Excessive destruction / hemolysis
Blood loss/hemorhage
Etiological Classification
Impaired/Defective RBC production
Abnormal bone marrow
Aplastic anemia
Myelofibrosis, Leukemia,
Cancer metastasis
Essential factors deficiency
Deficiency anemia : Fe, Vit. B12, Folic acid, etc
Anemia in renal disease : Erythropoietin
Aplastic Anemias
Anemia resulting from lack of functioning bone marrow.
High-dose radiation or chemotherapy for
cancer treatment or high doses of certain toxic chemicals, can damage stem cells of the bone marrow, followed in a few weeks by anemia.
People with severe aplastic anemia usually die
unless they are treated with blood transfusions
or by bone marrow transplantation
.Excessive destruction/ hemolysis of RBC
Different abnormalities of the RBCs, make the cells fragile, so they rupture easily as they go through the capillaries, especially through the spleen.
Even though the number of RBCs formed may be normal, or even much greater than normal, the life span of the fragile RBC is so short that the cells are destroyed faster than they can be formed, and serious anemia results
Etiological Classification
Cause of hemolysis:
Intrinsic (intracorpuscular) abnormalities:
Membrane defect : Hereditary spherocytosis Hereditary ovalocytosis, Hereditary elliptocytosis
Enzyme defect : G-6PD deficiency.
Hemoglobin defect : Thalassemia,
Sickle cell Anemia
Extrinsic (extracorpuscular) abnormalities
Antibody-mediated:
Rh disease (Erythroblastosis fetalis)
Transfusion reaction to blood transfusions
Infection:
Clostridium tetani
Malaria
Mechanical trauma to red blood cells
Blood Loss
Hemorrhage, results in a low concentration of RBCs
RBC concentration usually returns to normal within 3 to 6 weeks.
Cause:
Trauma or surgery, causing acute blood loss
Gastrointestinal tract lesions, causing either acute
bleeds (e.g. variceal lesions, peptic ulcers) or chronic blood loss
Infection by intestinal nematodes feeding on blood, such as hookworms and the roundworm
Etiological Classification
ANEMIA
morphologic classification
microcytic
MCV <80
normocytic
MCV 80-100
macrocytic
MCV >100
Morphological classification
Macrocytic Anemia
The condition of having erythrocytes which are too large, is called macrocytosis.
MCV > 100
Megaloblastic anemia
Causes: DNA replication disorders
Vit. B12 deficiency : pernicious anemia
Folic acid deficiency
inhibitors of DNA replication (poisons, drugs)
Chronic Alcoholism
William Murphy, discovered that
ingesting large amounts of liver seemed to cure the Anemia . George Minot and
George Whipple then were able to isolate
the vitamin B12 from the liver. All three
shared the 1934 Nobel Prize in Medicine.
Microcytic hypochromic Anemia
MCV < 80
characterized by small red blood cells (called microcytes).
Erythrocytes are usually hypochromic,
meaning that the red blood cells a lower- than-normal hemoglobin concentration.
therefore, anemia of this category is
described as "microcytic, hypochromic anaemia
".Morphological classification
Causes:
Heme synthesis defect
Iron deficiency anemia (the most common form of anemia)
Anemia of chronic disease (more commonly presenting as normocytic anemia)
Globin synthesis defect
Alpha-, and beta-thalassemia
Other abnormal hemoglobins
Sideroblastic defect
Hereditary sideroblastic anemia
lead toxicity
Remember
cause of microcytic hypochromic Anemia
T- Thallasemia
A- Anemia of chronic disease
I - Iron deficiency
L – Lead poisoning
S - Sideroblastic
Normocytic Normochromic Anemia
Normocytic anemia occurs when the overall hemoglobin levels are decreased, but the red blood cell size (mean corpuscular volume)
remains normal.
MCV - 80 – 100 Cause:
Acute blood loss
Anemia of chronic disease
Hemolytic anemia
Aplastic anemia
Morphological classification
Heart Failure
(specially during exercise)
Effect of Anemia
increase in the return of blood to the heart
hypoxia causes the peripheral tissue blood vessels to dilate Blood viscosity decreases
(may fall to as low as half the normal value)
increased cardiac output, as well as increased pumping workload on the heart.
Polycythemia
Definition
It is a disease state in which the proportion of blood volume that is occupied by red blood cells increases.
An increase in the no of red blood cells =absolute polycythemia
Due to decrease in the volume of plasma
=relative polycythemia
Polycythemia
Hematocrit — Polycythemia in the adult patient is suspected when the HCT is >48 or >52 % in Females and Males , respectively.
(The hematocrit (HCT) is expressed as the percent of a blood sample occupied by intact RBCs. )
Hemoglobin concentration — when the HGB is >16.5 or >18.5 g/dL in F and M, respectively.
Polycythemia Classification
RELATIVE
Reduced plasma volume (hemoconcentration) ABSOLUTE
• Primary (Erythropoietin normal or low) Also known as Polycythemia vera
Bone marrow cancer
• Secondary (High erythropoietin) Compensatory
Lung disease
High‐altitude living
Cyanotic heart disease Paraneoplastic
Erthropoietin secreting tumors
Primary Polycythemia
Polycythemia vera is caused by a genetic aberration in the
hemocytoblastic cells that produce the blood cells.
This causes excess production of RBCs.
the RBC count may be 7 to 8
million/mm3 and the hematocrit may be 60 to 70 percent.