Chapter 5 - RED BLOOD CELL STUDIES Flashcards by Arriane Cyrel (MTI)

Characteristics of a normal Red Blood Cell:
• 7 to 8 um in diameter:
• Average volume:
• Average surface area:
• Shape and Deformity:
• Cytoplasm:
• Average life span:

1.5 to 2.5 um in thickness

90 fL

160 um2

Discocyte/Discocyte; Flexible & deformable

uniformly pink without inclusions

120 days

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: used to measure the effective survival of RBCs in vivo.

Chromium-51 (51Cr)

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51Cr half-survival time range is

28 - 38 days.

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RBC Membrane Compositions:

Proteins (50%)
Lipids (40%)
Carbohydrate (10%)

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: Underlie the lipid layer and regulate membrane shape & deformability

RBC Membrane

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• Integral proteins:

Glycophorin A and component a (band 3)

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• Peripheral proteins:

Spectrin and Actin (form the cytoskeleton)

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• Phospholipids:
External surface:
Internal surface:

phosphatidyl choline, glycolipids & sphingomyelin

Cephalin, phosphatidylinositol & phosphatidy|serine

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: Amount depends upon the concentration of plasma cholesterol, bile acids, and the activityof the enzyme LCAT.

Cholesterol

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• Some serve as red cell antigens (e.g. ABH antigen)

Carbohydrate (10%)

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Anaerobic glycolysi s

Embden Meyerhof Pathway

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Major source of 2. red cells ATP

Embden Meyerhof Pathway

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oxidative glycolysis

Hexose Monophosphate Shunt/Pentose Phosphate Shunt

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generates NADPH and reduced glutathione in the presence of Glucose 6-PO4 dehydrogenase (G6PD). GSH protects the hemoglobin from oxidation by peroxides.

Shunt/Pentose Phosphate Shunt

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Generates 2,3DPG /2,3BPG

RapoportLuebering Shunt

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Reduction of methemoglobin by NADPH is more efficient in the presence of methemoglobin reductase (cytochrome b5 reductase) which serves as an intermediate electron carrier.

Methemoglobin Reductase Pathway

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As RBC ages, there is a decrease in its (?) and an increase in (?). This natural deterioration leads to its phagocytosis.

enzymes, ATP and size

density

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destruction of senescent red cells by splenic macrophages.

Extravascular (Macrophage-mediated)

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Hemoglobin undergoes degradation within the macrophage where iron is stored as ferritin, amino acids of globin are returned to the metabolic amino acid pool and protoporphyrin is converted to bilirubin which is released into the plasma and excreted by the liver in bile.

Extravascular (Macrophage-mediated)

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may be caused by the turbulent environment in the circulation

Intravascular destruction (Mechanical hemolysis)

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Hemoglobin is released into the plasma and can be filtered by the kidneys.

Intravascular destruction (Mechanical hemolysis)

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Plasma (?) salvage the released hemoglobin so that its iron is not lost in the urine

haptoglobin and hemopexin

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Biconcave disc
Normal

Normocyte

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Smaller RBCs, with diameter less than 7 µm

Microcyte

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Any defect that results in impaired Hb synthesis

Microcyte Hypochromic Anulocyte

Iron deficiency anemia;

Microcyte Hypochromic/Anulocyte Ellipto

Sideroblastic anemia

Microcyte Pappenheimer

Thalassemia

Microcyte Hypochromic/Anulo Ellipto Target BS PP

Anemia of Chronic Inflammation

Microcyte

Lead Poisoning

Microcyte BS CR

RBCs >9 µm in diameter, with an MCV >100 fL

Macrocyte

larger than 10 µmn diameter

Gigantocyte/ Megalocyte

-Accelerated erythropoiesis

Macrocyte Gigantocyte/ Megalocyte HJ BS

- Defective DNA synthesis

Macrocyte Gigantocyte/ Megalocyte

-In conditions where membrane cholesterol and lecithin levels are increased

Macrocyte Gigantocyte/ Megalocyte

Hemolytic anemia & Acute Blood Loss

Macrocyte Gigantocyte/ Megalocyte

Megaloblastic Process; Chemotherapy

Macrocyte Gigantocyte/ Megalocyte

Liver disease, Alcoholism

Macrocyte Gigantocyte/ Megalocyte

Presence of 2 distinct populations of red cells that may differ in size, shape or hemoglobin content

Dimorphic RBCs

anemia after transfusion

Dimorphic RBCs

ANISOCYTOSIS & POIKILOCYTOSIS GRADING Normal Slight 1+ 2+ 3+ 4+

5% 5 10% 10 25% 25 50% 50 75% > 75%

MACROCYTOSIS GRADING 1+ (slight) 2+ to 3+ (moderate) 4+ (marked)

25% 25% - 50% >50%

Homogenous with central palor Normal

Normochromic

RBCs show inc central pallor (exceeds 1/3 of the diameter of the red cell

Hypochromic

Thin & poorly hemoglobinized cells

Anulocyte

defect in hb synthesis due either to: decrease in heme synthesis defect in globin chain synthesis Iron Deficiency Anemia (IDA) Thalassemia

Hypochromic Anulocyte

Cells that lack central pallor and with reduced diameter

Spherocytic (Hyperchromic)

Defects in the cytoskeletal proteins

Spherocytic (Hyperchromic)

Hereditary and acquired spherocytosis

Spherocytic (Hyperchromic)

Area of central pallor is one-half of cell diameter

Area of pallor is two-thirds of cell diameter

Area of pallor is three-quarters

Thin rim of hemoglobin

: 1/3 to 2/3 of cells diameter

1+ (slight) central pallor

: more than 2/3

2+ to 3+ (moderate)

: thin rim on the periphery

4+ (marked)

Percentage of Polychromatophilic Cells Slight 1+ 2+ 3+ 4+

1 % 3 % 5 % 10 % >11 %

PcC/f 1+ 2+ 3+

( 1 3 polychromatophilic cells/field) ( 3 5 PcC/f) ( >5 PcC/f )

Range from egg-shape, slightly oval to sausage, rod, or pencil forms

Ovalocytes (Elliptocytes)

Hb appears to be concentrated at the two ends of the cell, leaving a normal central pallor area.

Ovalocytes (Elliptocytes)

decrease in skeletal membrane CHON band 4.1

Ovalocytes (Elliptocytes)

increase heat sensitivity of spectrin

Ovalocytes (Elliptocytes)

Hereditary elliptocytosis

Ovalocytes (Elliptocytes)

Small numbers may by acquired in: - iron deficiency, - megaloblastic anemia, - myelophthisic anemia, - thalassemias & sickle cell anemia

Ovalocytes (Elliptocytes)

Smaller in diameter than normal RBC

Spherocyte

With concentrated hb content

Spherocyte

No visible central pallor

Spherocyte

indicates a hemolytic process (hemolysis results from a membrane abnormality

Spherocyte

Hereditary Spherocytosis

Spherocyte

Autoimmune hemolytic anemia

Spherocyte Agglutination

Normal aging process

Spherocyte

Storage phenomenon

Spherocyte

Severe burns

Spherocyte

With irregularly sized & unevenly spaced spicules

Burr cell

Depletion of ATP

Burr cell

Exposure to hypertonic solution

Burr cell

May occur in situations that cause a change in tonicity of the intravascular fluid

Burr cell

Associated w/ renal insufficiency

Burr cell

What is the difference between a burr cell and an echinocyte?

With few (3-12) irregularly spaced, pointed spicules/thornlike projections of various lengths and widths

Acanthocytes

May be caused by changes in the ratio of plasma lipids

Acanthocytes

Associated w/ end stage liver disease

Acanthocytes

Alcoholic cirrhosis

Acanthocytes

PK deficiency

Acanthocytes

Congenital abetalipoproteinemia

Acanthocytes

Post-spenectomy

Acanthocytes Target Pappenheimer Cabot rings

Normal sized cell with an elongated or a slitlike mouth or stoma

Stomatocytes (Mouth cells)

cup-shaped

Stomatocytes (Mouth cells)

Membrane defect that results in high cellular sodium and low potassium content

Stomatocytes (Mouth cells)

Hereditary stomatocytosis

Stomatocytes (Mouth cells)

Rh null disease

Stomatocytes (Mouth cells)

Obstructive liver disease

Stomatocytes (Mouth cells)

Alcohol excess

Stomatocytes (Mouth cells)

myelodysplastic syndromes

Stomatocytes (Mouth cells)

hydroxyurea therapy

Stomatocytes (Mouth cells)

Hereditary stomatocytosis

Stomatocytes (Mouth cells)

With a central area or hb surrounded by a colorless ring and a peripheral ring of hb

Target Cells (Codocytes)

bell-shaped or tall hat shaped

Target Cells (Codocytes)

Increase in cholesterol & phospholipids.

Target Cells (Codocytes)

Excess surface area to volume ratio

Target Cells (Codocytes)

Hemoglobinopathies

Target Cells (Codocytes) Heinz PH BS

Thalassemia

Micro, Hypo/Anulo Ellipto, Target Cells (Codocytes) BS, PP

Post-splenectomy

Target Cells (Codocytes) Acanthocytes Pappenheimer Cabot

Poikilocytes Secondary to TRAUMA Two pathways of fragmentation are recognized:

Alteration of normal fluid circulation (DIC, TTP, MAHA) Intrinsic defects of the red cell (spherocytes, antibody altered red cells, inclusions)

Schistocytes (Schizocytes) Fragments of RBCs varying in shapes

Helmet cells Triangular cells keratocytes

Schistocytes (Schizocytes) fragmentation due to:

1. Exposure of cells to abnormal conditions 2. Contact with fibrin strands or damaged endothelium. 3. Intrinsic defects of RBCs

Hemolytic anemias

Schistocytes (Schizocytes) Keratocytes, Bite Cells, Degmacytes

erythrocytes with a pair of spicules or 'horns' surrounding a gap in the cell outline.

Keratocytes, Bite Cells, Degmacytes

Results from removal of a Heinz body from a cell by splenic macrophages; or when an erythrocyte is caught on a fibrin strand.

Keratocytes, Bite Cells, Degmacytes

G6PD deficiency

Keratocytes, Bite Cells, Degmacytes Heinz

Half-moon/ crescent cells; large pale- pink staining ghost of the RBC

Semilunar bodies

Frequently observed in malaria and in other conditions causing overt hemolysis

Semilunar bodies

Overt hemolysis

Semilunar bodies

Pear-shaped with a single elongated point

Teardrop Cells (Dacrocytes)

Cuased by squeezing & fragmentation during splenic passage

Teardrop Cells (Dacrocytes)

Myelofibrosis

Teardrop Cells (Dacrocytes)

Presence of inclusion bodies

Teardrop Cells (Dacrocytes)

Myelophthisic anemia

Ellipto Teardrop Cells (Dacrocytes)

Pernicious anemia

Teardrop Cells (Dacrocytes)

B-thalassemia

Teardrop Cells (Dacrocytes)

Smaller than spherocytes

Microspherocytes & Pyropoikilocyte

Also lack central

Microspherocytes & Pyropoikilocyte

Results from repeated fragmentation of red cells & from thermal damage to cell membrane

Microspherocytes & Pyropoikilocyte

Severe burns

Spherocyte Microspherocytes & Pyropoikilocyte

Hereditary pyropoikilocytosis

Microspherocytes & Pyropoikilocyte

Other appearances related with hemolysis

Blister cell

with thinned portion

Blister cell

- appear like pinched bottle

Knizocytes

- distorted red cells

Pyknocytes

Thin and elongated with pointed ends.

Drepanocytes/Sickle cells

Polymerization of hemoglobin

Drepanocytes/Sickle cells

Sickle cell anemia

Ellipto Drepanocytes/Sickle cells

With one or more fingerlike, blunt-pointed projections that protrude from the cell membrane leaving a pale area at the opposite end

Hb SC crystal

Hexagonal; Both ends are blunt

Hb CC crystal

Formed within the membrane

Hb CC crystal

Helmet cells Grading

1+ = 1 to 5/field 2+ = 6 to 10/field 3+ = >10/field

Teardrop RBC Grading

1+ = 1 to 5/field 2+ = 6 to 10/field 3+ = >10/field

Acanthocytes Grading

1+ = 1 to 5/field 2+ = 6 to 10/field 3+ = >10/field

Schistocytes Grading

1+ = 1 to 5/field 2+ = 6 to 10/field 3+ = >10/field

Spherocytes Grading

1+ = 1 to 5/field 2+ = 6 to 10/field 3+ = >10/field

Ovalocytes Grading