Transcript Document 7563478

MLAB 1415: Hematology
Keri Brophy-Martinez
Chapter 8: Anemia
Part Three
RBC Shape Variations

Alterations in the shape of the RBC is
called poikilocytosis.
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Target Cells (Codocytes)
Occur due to an increased
red blood cell surface area.
 Appear as "targets" on
peripheral blood
smear. Have a pale central
area with most of the
hemoglobin around the rim
of the cell.
 Are always hypochromic.
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Target Cells (Codocytes)
Mechanism in formation is related to excess
membrane cholesterol and phospholipid, and to
decreased cellular hemoglobin.
 Osmotic fragility is decreased.
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Target Cells (Codocytes)

Seen in patients with:
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Liver disease
Hemoglobin C Disease or Trait
Post-splenectomy
Iron Deficiency Anemia
Any Hemoglobin Abnormality
Can be artifactual
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Target Cells (Codocytes)
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Spherocytes
Have a low surface-tovolume ratio.
 Smaller than normal red cell;
hemoglobin relatively
concentrated; and, have no
area of central pallor.
 Shape change is irreversible.
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Spherocytes
Several mechanisms
for formation, but all
involve loss
of membrane; aging,
antibody coating or
genetic defect
 Is the final stage for
red cells before they
are sequestered in
the spleen.
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Spherocytes
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Seen in patients with:
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Activated complement
Immune Hemolytic Anemia
Hereditary Spherocytosis
Post-Transfusion
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Spherocytes
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Ovalocytes and Elliptocytes
Ovalocytes may appear normochromic or
hypochromic; normocytic or microcytic.
 Hemoglobin concentrated at both ends
 Exact mechanism of formation unknown.
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Ovalocytes and Elliptocytes
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Ovalocytes associated
with:
◦ Myelodysplastic Syndromes
◦ Thalassemias
◦ Megaloblastic Processes
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Elliptocytes associated
with:
◦ Iron Deficiency Anemia
◦ Hereditary Elliptocytosis
◦ Idiopathic Myelofibrosis
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Ovalocytes and Elliptocytes
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Stomatocytes
Red cell of normal
size
 Slit-like central area
of pallor
 Exact mechanism of
formation unknown
 Usually artifactual
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Stomatocytes

Osmotic fragility
increased (more
permeable to sodium).
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Stomatocytes
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Associated with following disorders:
◦ Hereditary Stomatocytosis
◦ Hemolytic, Acute Alcoholism
◦ Rh Null Phenotype
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Sickle Cells (Drepanocytes)
Have at least one
pointed end.
 Surface area of cell
much greater than
normal cell.
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Sickle Cells (Drepanocytes)
Low oxygen tension
causes hemoglobin to
polymerize, forming
tubules that line up in
bundles to deform cell.
 Most sickle cells can
revert back to normal
shape when
oxygenated.
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Sickle Cells (Drepanocytes)
 Associated
with the following
disorders:
◦ Sickle Cell Anemia
◦ Hemoglobin C Disease
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Sickle Cells (Drepanocytes)
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Acanthocytes
Normal or slightly
smaller size
 Possess 3-12 thorny
projections of
uneven length along
periphery of cell
membrane.
 Projections are blunt
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Acanthocytes
Specific mechanism of
formation unknown.
 Contain increased
cholesterol-tophospholipid ratio.
 Surface area
increased
 Susceptible to
removal by spleen
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Acanthocytes
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Possible pathologies include:
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Alcohol Intoxication
Pyruvate Kinase Deficiency
Congenital Abetalipoproteinemia
Vitamin E Deficiency
Post-Splenectomy
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Acanthocytes
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Fragmented Cells
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Includes:
◦ Burr Cells
◦ Helmet Cells
◦ Schistocytes
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Fragmentation is defined
as a loss of a piece of cell
membrane that may or
may not contain
hemoglobin.
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Fragmented Cells
Two pathways that lead to fragmentation:
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Alteration of normal fluid circulation (vasculitis,
malignant hypertension, heart valve
replacement).
Intrinsic defects of red cell that make it less
deformable (spherocytes and antibody-covered
red cells).
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Fragmented Cells
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Burr Cells (Echinocytes)
Red cells with 10-30
evenly spaced
spicules over the
surface of the cell.
 Normocytic and
normochromic.
 In large numbers, are
an artifact of sample
contamination.
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Burr Cells (Echinocytes)
"True" burr cells occur in small numbers in
uremia, heart disease, stomach cancer,
bleeding peptic ulcers, and in patients with
untreated hypothyroidism.
 Seen in liver disease, renal disease, and burn
patients.
 May occur in any situation that causes
change in tonicity of intravascular fluid
(dehydration).
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Helmet Cells (Bite Cells)
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Usually have two
projections surrounding
an empty area of red cell
membrane.
Looks as if cell has had a
bite taken out of it.
Caused by spleenic
pitting and impalement
of the RBC on fibrin
strands
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Helmet Cells (Bite Cells)
In conditions where
red cells have large
inclusion bodies (such
as Heinz bodies
 G6PD deficiency.
 May be seen in patients
with pulmonary emboli,
and disseminated
intravascular
coagulation (DIC).
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Schistocytes
Extreme cell
fragmentation
 Cell is missing whole
pieces of
membrane.
 Causes bizarre
shapes of red cells.
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Schistocytes
Caused by loss of
membrane by
mechanical means
 See in patients with
microangiopathic
hemolytic anemia, DIC,
heart valve surgery, or
severe burns.
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Teardrop Cells
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Appear as pear-shaped
cells. Length of tail
varies. May be
microcytic, normocytic,
or macrocytic.
Exact formation
process
unknown. Commonly
seen in red cells that
contain large inclusion
bodies.
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Teardrop Cells
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Most commonly
seen in idiopathic
myelofibrosis,
thalassemia, and iron
deficiency anemia.
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References
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Harmening, D. M. (2009). Clinical Hematology and
Fundamentals of Hemostasis. Philadelphia: F.A
Davis.
McKenzie, S. B., & Williams, J. L. (2010). Clinical
Laboratory Hematology . Upper Saddle River:
Pearson Education, Inc.
http://www.ezhemeonc.com/index.php/hematolog
ical-disorders/
http://www.wiwe.net/irene/lab/chemheme/heme/
microscope/stomatocyte.htm
http://home.ccr.cancer.gov/oncology/oncogenomic
s/WEBHemOncFiles/Review%20of%20Terms.html