Pathological Polycythemia

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.

 

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