morphology of red blood cells

Red cell morphology

Normal Red CellFragile, Biconcave, disk like structure.

Have smooth round surface

Diameter ranges from 7.5-7.8µm.

Appears to be of the same size as the nucleus of the small lymphocyte.

Have no nucleus

Whole cell is filled with the HAEMOGLOBIN.

The red colour of red cells is due to the presence or haemoglobin

RBCs survive for approximately 120 days in the peripheral blood

Normal red cell

Normocytic & Normochromic•Normocytic: The term used to express RBCs of normal size is

normocytic.

•Normochromic: Mature red blood cells, under normal

circumstances, will also have an appropriate hemoglobin content, giving

them a red-orange appearance on Wright-stained smears. These cells

will display a central pallor no larger than 3 microns in diameter. This

normal morphology is indicated by the term normochromic.

•It is paramount for RBCs to contain an adequate amount of

hemoglobin for the purpose of transporting oxygen to the tissues and

carbon dioxide back to the lungs.

ABNORMALITIES OF RED CELLS

3 types of abnormalities may occur in red blood cells

i.Anisocytosis: If the size of RBC varies, in the same blood film,

beyond normal limits, it is termed anisocytosis.

ii.Poikilocytosis: When the shapes of RBCs vary more than

expected in normal individuals, in the blood film, it is termed

poikilocytosis.

iii.INCLUSIONS IN RBC: abnormal structures present in red

cells having certain staining charecteristics

Anisocytosis:

Poikilocytosis:

Anisocytosis:

Variations in size are as follows:1)MACROCYTOSIS: When the average size of RBC is more than normal, it is termed macrocytosis.Causes Of Macrocytosis:liver diseasemegaloblastic anaemiaaplastic anaemia,obstructive airway diseaseexcess of alcohol,

Cont…MIROCYTOSIS: When the average size of RBC ina blood film is less than normal it is termed microcytosis.Causes Of Microcytosis:iron deficiency anaemiathalassaemia.There will decrease in MCV.Should be distingused from red cell fragmentation. If in association with decrease in MCV it will be microcytosis.

POIKILOCYTOSISAbnormality in shape may be of the following types:1.Spherocytes2.Ovalocytes3.Burr cells4.Crenated red cells5.Schistocytes6.Tear drop cells7.Acanthocytes8.Target cells9.Sickle cells 10.Pencil cells:

Cont….Spherocytes: small densely staining spherical red cells with no central pallor area

Causes:•Haemolytic anaemia• drugs induced•snake venom•infection with C. perfringens•hereditary spherocytosis•ABO haemolytic disease of the newborn

CONTINU…..

Ovalocytes: these are oval shaped red cells. About 10% RBC in a normal blood film, particularly at the tail end, appear oval and less commonly elliptical in shape.

Causes:•Iron deficiency anaemia,•megaloblastic anaemia

Cont….

Pencil cells: Elongated narrow red cellsFeature of iron deficiency anaemia

Cont….Target : these are hypochromic red cells showing central spot of HbCauses:•Thalassaemia syndromes•sickle cell disease•HbC disease•HbD disease•obstructive jaundice•liver disease•postsplenectomy

Cont....Sickle cells: These are thin crescent shaped, or boat shaped cells elongated, deeply staining red cells with pointed ends.These may be straight, curved or of various other shapes. These are produced by polymerisation of HbS in sickle cell disease.,Causes: Sickle cell disease, including sickle cellanaemia (S/S) sickle cell/ thalassaemia,

Cont....

Sickle cells:

Cont....Acanthocytes: Irregularly crenated cells with irregularly spaced sharp projections. Small number of spicules of inconstant length, thickness , shape ,irregularly disposed over the surface of the cell.

Causes: Associated with abnormal phospholipids metabolism or with inherited abnormalities of red cell membrane proteins. After spleenectomy, hypospleenism and in sever liver disease.

Cont….

Tear drop : Cells shaped like tear drops. It is also called pear shaped cell. these cells are usually found In iron deficiency anaemia

Cont….

Schistocytes: These are fragmented red blood cells of various shapes and sizes.

Cause: Associated with red cell damage due tosevere burns, drugs, toxins, DIC. Also found in uraemia

CRENATED RED CELLS: Echinocytes or crenated cells have evenly distributed blunt spicules of uniform size on their surface.A few crenated cells are seen in the blood film of healthy subjects.These are formed if anticoagulated blood is allowed to stand for long periods

Cont….

Burr cells: Burr cells are also echinocytes but their spicules are reversible.

Causes: •Uraemia•acute blood loss•Pyruvate kinase deficiency

Cont….STOMATOCYTOSISIn dry films , the central biconcave area appears slit like. In wet preparations, the stomatocyte is a cup shaped red cell.Also occurs as an artifact because the change can be produced by decrease pH .

They are found in:•Hereditary stomatocytosis•Liver disease•Alcoholism

Cont…Hypochromasia or hypochromic red cells: these are the red cells which are deficient in Hb. They appear ring shaped because the centeral palor is increased.

They are found in• iron deficiency anaemia•Thalassaemia•sideroblastic anaemia

Dimorphic appearance

It is the Presence of two different populationsof red cells, e.g:• hypochromic cells with normal red cells, or•hypochromic cells with macrocytic cells

Commonly seen following successful treatment for anemia and post-blood transfusion

INCLUSIONS IN RBC:

Abnormal structures which are present In red cells are called inclusions. These are normally abscent in red cells.These includes:

•Howell-Jolly bodies•Cabot Rings •Heinz Bodies•Siderocytes•Basophilic stippling•Malarial parasite

Cont….Howell-Jolly bodies:These are small (<1 μm in diameter) rounded fragments of the nuclear material staining reddish-blue to blue-black. These usually occur singly in RBC but may be multiple. During maturation in the bone marrow erythrocytes normally expel their nuclei, but in some cases a small portion of DNA remains.Causes:•splenectomy •Splenic atrophy •alcoholism•sickle cell anaemia•megaloblastic anaemia.

Cont….Cabot rings: These are Reddish-blue threadlike rings in

RBCs. These are remnants of the nuclear membrane

and appear as a ring or figure 8 pattern.

Very rare finding in patients

with Megaloblastic anemia

severe anemia's

lead poisoning

and dyserythropoiesis

Cont….

Heinz Bodies:•Represent areas of denatured hemoglobin. They appear highly

refractile bodies near the pariphery of cell In unstained wet cover

glass preparation.

•With a supravital stain like crystal violet, Heinz bodies appear as

round blue precipitates.

•Presence of Heinz bodies indicates red cell injury and is usually

associated with G6PD-deficiency.

Heinz Bodies

Siderocytes:

these are red cells containing non haemoglobin iron granules.

Iron granules appear bright blue.

They are found in haemolytic anaemia.

Cont….Basophilic stippling: These are fine to coarse, deep blue to purple,

small but multiple inclusions of varying sizes.

They are given the name due to purplish colour.

Normally one in 10000 cells may show basophilic stippling.

Increased no is seen in:

•Thalassaemia

•megaloblastic anaemia

•liver disease

•lead poisoning

•infections

Cont….Malarial parasite:Malarial parasite may be present in red cells in verious forms like:

•Trophozoite•Schizont•gametocytes

ROULEAUX FORMATIONA stack like arrangement of red blood cells

in blood or in diluted suspensions of blood

in which their biconcave surfaces are next

to each other.

The RBC's here have stacked together in

long chains. This is known as "rouleaux

formation"

It happens with increased serum proteins,

particularly fibrinogen and globulins.

CHANGES ASSOSIATED WITH A COMPANSATORY INCREASE IN

ERYTHROPOIESES

POLYCHROMASIARefers to having red blood cell of

multiple colors, particularly gray-

blue.

This is due to differing amounts

of haemoglobin in each cell , which

is due to inappropriate, premature

release from the bone marrow:

ERYTHROBLASTEMIAThe presence in the peripheral blood of abnormally large number nucleated red cells.They are found in sever anemia.Large number is characteristic of haemolytic disease of newborn.After spleenectamy.Sickle cell anemia.Leukemia .Myelofibrosis.

PIMS