PATHOLOGICAL VARIATIONS
Pathological
Polycythemia
Pathological polycythemia is the
abnormal increase in the RBC count. Red cell count increases above 7 million/ cu
mm of the blood. Polycythemia is of two types, the primary polycythemia and
secondary polycythemia.
Primary Polycythemia –
Polycythemia Vera
Primary polycythemia is otherwise
known as polycythemia vera. It is a disease characterized by persistent
increase in RBC count above 14 million/cu mm of blood. This is always
associated with increased white blood cell count above 24,000/cu mm of blood.
Polycythemia vera occurs in myeloproliferative disorders like malignancy of
red bone marrow.
Secondary
Polycythemia
This is secondary to some of the
pathological conditions (diseases) such as:
1. Respiratory disorders like
emphysema.
2. Congenital heart disease.
3. Ayerza’s disease (condition
associated with hypertrophy of right ventricle and obstruction of
blood flow to lungs).
4. Chronic carbon monoxide poisoning.
5. Poisoning by chemicals like
phosphorus and arsenic.
6. Repeated mild hemorrhages.
All these conditions lead to hypoxia
which stimulates the release of erythropoietin. Erythropoietin stimulates the
bone marrow resulting in increased RBC count.
Anemia
Abnormal decrease in RBC count is
called anemia.
VARIATIONS IN SIZE OF RED BLOOD CELLS
Under physiological conditions, the
size of RBCs in venous blood is slightly larger than those in arterial
blood. In pathological conditions, the
variations in size of RBCs are:
1. Microcytes (smaller cells)
2. Macrocytes (larger cells)
3. Anisocytes (cells with different
sizes).
MICROCYTES
Microcytes are present in:
i. Iron-deficiency
anemia
ii. Prolonged forced breathing
iii. Increased osmotic pressure in
blood.
MACROCYTES
Macrocytes are present in:
i. Megaloblastic anemia
ii. Decreased osmotic pressure in
blood.
ANISOCYTES
Anisocytes occurs in pernicious
anemia.
VARIATIONS IN SHAPE OF RED BLOOD CELLS
Shape of RBCs is altered in many conditions
including different types of anemia.
1. Crenation: Shrinkage as in
hypertonic conditions.
2. Spherocytosis: Globular form
as in hypotonic conditions.
3. Elliptocytosis: Elliptical
shape as in certain types of anemia.
4. Sickle cell: Crescentic
shape as in sickle cell anemia.
5. Poikilocytosis: Unusual
shapes due to deformed cell membrane. The shape will be of flask, hammer
or any other unusual shape.
VARIATIONS IN STRUCTURE OF RED BLOOD
CELLS
PUNCTATE BASOPHILISM
Striated appearance of RBCs by the
presence of dots of basophilic
materials (porphyrin)
is called punctate basophilism. It occurs in conditions like lead poisoning.
RING IN RED BLOOD
CELLS
Ring or twisted strands of basophilic
material appear in the periphery of the RBCs. This is also called the
Goblet ring. This appears in the
RBCs in certain types of anemia.
HOWELL-JOLLY BODIES
In certain types of anemia, some
nuclear fragments are present in the ectoplasm of the RBCs. These nuclear fragments
are called HowellJolly bodies.
0 Comments