Download Hemolysis-a.v.

Hemolysis
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Increased cell destruction
Rate of destruction exceeds the capacity of
the bone marrow to produce red blood cells
(RBC)
Normal RBC survival time is 110-120 days
Approximately 1% of RBC are removed each
day and replaced by the marrow to maintain
the RBC count
Hemolysis
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During hemolysis RBC survival is
shortened and increased marrow activity
results in a heightened reticulocyte
percentage
Hemolysis can be divided into two
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Intravascular hemolysis
Extravascular hemolysis
Hemolysis
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Extravascular hemolysis
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The degradation of Hb results in the biliary
excretion of heme pigments and increased
fecal urobilinogen
Gallstones composed of calcium
bilirubinate may be formed in children as
young as 4 years of age
Hemolysis
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Intravascular hemolysis
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Hb binds to haptoglobin and hemopexin both of
which are reduced
Oxidized heme binds to albumin to form
methemalbumin which is increased
When the capacity of these binding molecules is
exceeded, free Hb appears in the plasma
(evidence of intravascular hemolysis)
When the tubular reabsorbtive capacity of kidneys
for Hb is exceeded free Hb appears in the urine
Hemolytic anemia
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Hemolysis
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A feature of hemolytic anemia is a reduction
in the normal red cell survival of 120 days
The premature destruction of RBC may result
from corpuscular abnormalities such as
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Increased cell destruction
Hb defects, abnormalities of RBC enzymes or
defects of RBC membrane
Other defects may result from
extracorpuscular abnormalities and may be
due to immune or non-immune mechanisms
Hemolytic anemia
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The approach to the diagnosis of
hemolytic anemia should include
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Consideration of the clinical features
suggesting hemolytic disease
Demonstration of the presence of
hemolytic process by laboratory means
Establishment of the presice cause of the
hemolytic anemia by special hematologic
investigations
Hemolytic anemia-Clinical features(1)
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The following clinical features suggest
hemolysis
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Age: anemia and jaundice in an Rh(+) infant born
to a Rh(-) mother or a group A or B infant born to
a group O mother
History of anemia, jaundice or gallstones in family
Persistent/ recurrent anemia associated with
reticulocytosis
Anemia unresponsive to hematinics
Intermittent/persistent indirect hyperbilirubinemia
Hemolytic anemia-Clinical features(2)
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Splenomegaly
Hemoglobinuria
Presence of multiple gallstones
Chronic leg ulcers
Development of anemia or hemoglobinuria
after exposure to certain drugs
Dark urine
Hemolytic anemia-laboratory findings
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Reduced cell survival and evidence of
accelerated Hb catabolism
Evidence of increased erythropoiesis
Hemolytic anemia-laboratory findings
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Accelerated Hb catabolism
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Extravascular
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Raised unconjugated bilirubin
Raised fecal and urinary urobilinogen
Intravascular
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Hemoglobinuria
Low/absent plasma haptoglobin
Raised plasma methemalbumin
Hemolytic anemia-laboratory findings
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Increased erythropoiesis (response to a
reduction in Hb)
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Reticulocytosis
Increased MCV
Increased normoblasts in peripheral blood
Spesific morphological abnormalities
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Sickled cells, target cells, spherocytes
Erhytroid hyperplasia of bone marrow
Expansion of marrow space
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Prominence of frontal bones, broad cheek bones,
widened intratrabecular spaces, hair-on-end appearance
of skull radiographs
normal
Hypochromic,
microcytes
macrocytes
Target cells
schistocytes
Tests used to establish a spesific cause of
hemolytic anemia (1)
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Membrane defects
(Hereditary spherocytosis,
elliptocytosis, stomatosis, acantocytosis)
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Blood smear
Increased RBC osmotic fragility
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(spherocytes lyse in higher concentrations of saline than
normal RBC)
Autohemolysis at 24 and 48 hours
Enzyme defects
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(G6PD and pyruvate kinase)
Heinz body preparation
Autohemolysis test
Screening tests for enzyme deficiencies
Tests used to establish a spesific cause of
hemolytic anemia (2)
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Hemoglobin defects
(sickle cell disease,
thalassemias)
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Blood smear, sickle cell, target cell
Sickling test
Hemoglobin electrophoresis
HbF determination
Tests used to establish a spesific cause of
hemolytic anemia (3)
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Immune hemolytic anemia
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Isoimmune
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Autoimmune
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Mismatched blood transfusion
Hemolytic disease of the newborn
Action of Ig
Idiopathic, secondary to number of conditions
Coombs’ test (+)
Tests used to establish a spesific cause of
hemolytic anemia (4)
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Non-immune hemolytic anemia
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Infections, drugs, underlying hematologic
disease- microangiopathic HA,
hypersplenism
Coombs’ test (-)
Congenital hemolytic anemias
Membrane defects
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Enzyme defects
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G6PD deficiency
Hemoglobin defects
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Hereditary spherocytosis(HS)
ıntracorpuscular
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- thalassemia (quantitative hemoglobinopathies)
HbS (qualitative hemoglobinopathies)
Hemolytic disease of the newborn (isoimmune)
Hereditary spherocytosis
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Familial hemolytic disorder
Marked heterogenicity of clinical features
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Asymptomatic condition
Fulminant hemolytic anemia
The morphologic hallmark of HS
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Microspherocyte
Caused by loss of membrane surface area
Abnormal osmotic fragility
Hereditary spherocytosis
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HS usually is transmitted as an
autosomal dominant trait
An autosomal recessive mode of
inheritance also occurs
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20-25% of all HS cases
HS is encountered worldwide
Hereditary spherocytosis
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An intrinsic genetic defect causes
defects in membrane proteins
The major complications
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Aplastic or megaloblastic crisis
Hemolytic crisis
Cholecystitis and cholelithiasis
Severe neonatal hemolysis
Hereditary spherocytosisPathophysiology
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HS erythrocytes are caused by membrane
protein defects resulting in cytoskeleton
instability
Four abnormalities in red cell membrane
proteins have been identified
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Spectrin deficiency alone (most common)
Combined spectrin and ankyrin deficiency
Band 3 deficiency(10-20% of patients)
Protein 4.2 defects (common in Japan)
Hereditary spherocytosisPathophysiology
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Spectrin deficiency
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Loss of erythrocyte surface
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Spherical RBC
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Hemolysis primarily confined to the spleen
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Culled rapidly from the circulation by the spleen
 Splenomegaly
Extravascular hemolysis
Biochemical spectrin deficiency and the degree of
spectrin deficiency are reported to correlate with
the extent of spherocytosis, the degree of
abnormality on osmotic fragility test results and
the severity of hemolysis
Hereditary spherocytosisPathophysiology
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Ankyrin defects
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Ankyrin is the principal binding site for spectrin on
RBC membrane
A proportional decrease in spectrin content occurs
although spectrin synthesis is normal
75-80% of patients with autosomal dominant HS
have combined spectrin and ankyrin deficiency
Deletion of chromosome 8 are shown to have a
decrease in RBC ankyrin content
Hereditary spherocytosisClinical findings
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Anemia
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Jaundice
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Splenomegaly
Clinical features of HS
Hereditary spherocytosisClinical findings(2)
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Anemia or hyperbilirubinemia may be of such
magnitude as to require exchange transfusion
in the neonatal period
Anemia is mild to moderate
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Sometimes severe/not present
In patients with mild HS cholelithiasis may be
the first sign of underlying disease
Moderate HS (most common, 60-75%)
Mild HS (20-30%)
Severe HS (5%, requires RBC transfusions)
Hereditary spherocytosisLaboratory findings
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Minimal or no anemia
Reticulocytosis
Increased MCHC
Spherocytes on the peripheral blood smear
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Hyperbilirubinemia
Abnormal osmotic fragility test
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Howell-Jolly bodies may be seen
hemolysis of HS cells may be complete at a solute
concentration that causes little or no lysis of normal cells
LDH increased
Increased unconjugated bilirubin
Looking for abnormalities in spectrin, ankyrin,
band 3 (not routine)
Hereditary spherocytosisTreatment
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Neonates
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Aplastic crisis
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Phototherapy/exchange transfusion
RBC transfusion
Folic acid supplementation to prevent
megaloblastic crisis
Splenectomy (after 6 years of age)
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Increased Hb level
Decreased reticulocyte count
Appereance of Howell-Jolly bodies and target cells
Thrombocytosis
Glucose 6 phosphate dehydrogenase
deficiency (G6PD)
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X-linked disorder
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Homozygous women are found in populations in which
the frequency of G6PD is high
Heterozygous carrier women can develop hemolytic
attacks
Polymorphic with more than 300 reported
variants
The highest prevalance rates are found in
tropical Africa, the Middle East, some areas of
Mediterranean (severe forms)
Glucose 6 phosphate dehydrogenase
deficiency- Pathophysiology
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G6PD enzyme catalyzes the oxidation of
glucose-6-phosphate to 6phosphogluconate while reducing the
oxidized form of nicotinamide adenine
dinucleotide phosphate (NADP+) to
nicotinamide adenine dinucleotide
phosphate (NADPH)
Glucose 6 phosphate dehydrogenase
deficiency- Pathophysiology
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NADPH
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Protects the cells against oxidative stress
Required cofactor in many biosynthetic
reactions
Maintains glutathion in its reduced form
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Glutathion acts a scavanger for dangerous
oxidative metabolites in the cell
Converts harmful hydrogen peroxide to water
with the help of glutathion peroxidase
Glucose 6 phosphate dehydrogenase
deficiency- Clinical findings
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The most common clinical feature is no
symptoms
Symptomatic patients
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Neonatal jaundice
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Acute hemolytic anemia
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Appears by age 1-4 days
Often requires exchange transfusion
Results from stress factors such as oxidative drugs or
chemicals, infection or ingestion of fava beans
Jaundice and splenomegaly may be present during
crisis
Glucose 6 phosphate dehydrogenase
deficiency- Laboratory findings
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Anemia
Reticulocytosis
Activity of G6PD is low (after hemolysis)
Indirect hyperbilirubinemia
Serum haptoglobin levels will be decreased
Formation of bodies which consist of
denaturated hemoglobin
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Heinz body
Glucose 6 phosphate dehydrogenase
deficiency- Treatment
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Avoid oxidant drugs
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Antimalarial drugs, nitrofurantoin, nalidixic acid,
ciprofloxacin,methylene blue, chloramphenicol,
phenazopyridine, vit K analogs, sulfonamides,
acetanilid, doxorubicine, isobutyl nitratre,
naphtalene, phenylhydrazine, pyridoxin
Exchange transfusion
RBC transfusion
Thalassemia
(Cooley’s anemia, Mediterranean Anemia)
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Genetically determined defect in Hb synthesis
An inability to manufacture sufficient quantities of
globin chains
In the adult there are 3 Hb types normally present
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Hb A 22 (95% of total)
Hb A2 22 (3% of total)
HbF 22 (2% of total)
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During fetal life the majority of Hb
During embryonic life at least 2 different Hbs are
produced
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Gowers 2 22 chains
Gowers 1 4 chains
The manufacture of each of these chains is controlled by
spesific genes
Thalassemia
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In thalassemia there is a genetic failure
in the production of globin chains
Failure of production of  and  chains
is the most common
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 thalassemia
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a failure of beta chain production
 thalassemia
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a failure of alpha chain production
Beta Thalassemia
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The genes controlling beta chain
production are located on chromosome
11
 thalassemia major
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If both genes fail
 thalassemia minor
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If only one gene fails
Beta Thalassemia minor
(Heterozygous) (B+)
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Most common of thalassemias
Beta chain production is less than normal
Alpha chain production continues at a near
normal rate
Decreased level of HbA
Excess alpha chains stimulates the increased
production of delta chains
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Increased amount of HbA2
Rate of gamma chain production is greater
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Increased amount of HbF
Beta Thalassemia minor
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These patients are not severely anemic
These patients can be provided appropriate
genetic counselling
Hb, Hct are decreased
RBC count is not as low as the Hb and Hct
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Bone marrow produce the cells but cannot fill
them with Hb
RBCs are microcytic and hypochromic
Normal RDW
Beta Thalassemia minor
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MCV is slightly decreased
MCH is decreased
MCHC is normal
WBC count is normal
Reticulocyte count is relatively increased
Bone marrow is either normal or undergoes
slight erythroid hyperplasia
Serum iron,ferritin is normal
Bilirubin slightly increase due to
intramedullary hemolysis
Beta Thalassemia minor
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Hb studies
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HbA decreased
HbA2 increased
HbF slightly increased to normal
Beta Thalassemia major
(homozygous)(B0)
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Complete failure of beta chain production
Raised levels of HbA2 and HbF
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HbF has a very high affinity for oxygen (poor
oxygen deliverer)
Only functional Hb is HbA2
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The patient is hypoxic
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İncreased erythropoietin production
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Stimulates the marrow to maximum
 Typical facial appereance
Splenomegaly
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Extramedullary hemopoiesis
Beta Thalassemia major
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Patients develop a life threatening anemia by
one or two months (mostly often 6 months)
Severe anemia (Hb:2-3 mg/dl)
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MCV, MCH, MCHC are all decreased
RDW is increased
Hypochromic microcytic RBC
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Hct and RBC count are also decreased
Anisocytosis, poikilocytosis, target cells
Reticulocytosis
WBC is increased at the beginning
Beta Thalassemia major
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Bone marrow undergoes erythroid
hyperplasia
Serum Fe increased/normal
Ferritin increased/normal
Hb electrphoresis
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HbA decreased
HbA2 variable
HbF increased
Beta Thalassemia major
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The patients must be supported with blood
transfusions which result in iron overload
Unless iron is removed with appropriate
chelation therapy these patients die of
hemosiderosis
Splenectomy
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When the yearly transfusion requirement of
packed red cells exceeds 200-250 ml/kg
Bone marrow transplantation
Alpha thalassemia
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Four genes coding for alpha chain
production
These genes are located on
chromosome 6
There are at least five forms of alpha
thalassemia depending on the number
and location of abnormal genes
Hydrops fetalis-
Homozygous alpha thalassemia
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All genes are abnormal
There is no alpha chain production
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No HbF production and death in utero
At autupsy the cord blood shows severe
anemia
There is no HbA and HbF on electrophoresis
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most of the Hb is HbBart’s which consists of 4
gamma chains
Hemoglobin H disease
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Three genes are abnormal and one gene is
coding for alpha chains
Limited production of HbF in utero and HbA
after birth
The excess gamma chains form HbBart’s and
the excess beta chains form HbH
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Unstable hemoglobins precipitate in the cell
Premature destruction in the marrow and spleen
with splenomegaly
Infant is anemic at birth
RBC and hct count are also decreased
Hemoglobin H disease
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MCV, MCHC, MCH decreased
RDW is increased
Microcytosis, hypochromia
Reticulocyte count is slightly increased
Bone marrow undergoes erythroid
hyperplasia
Serum iron,ferritin increased
Hb electrophoresis
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Hb Bart’s increased at birth
Hb Bart’s 2-10% later
HbH 5-40%
HbA and A2 decreased
Heterozygous alpha thalassemia
(minor)
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Depends on whether or not the two deleted genes
are on the same chromosome
In alpha th O, both genes are absent from the same
chromosome
In alpha th +, one gene is missing from each
chromosome
In both forms
 Minor changes
 Mild anemia
 MCV and MCHC are borderline low
Hb electrophoresis is normal with increased levels of
HbBart’s if the cord blood is electrophoresed
Alpha thalassemia silent
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Only one of the four genes is abnormal
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There is a near normal production of
alpha chains with very few if any clinical
or laboratory changes
Beta thalassemia variants
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Delta/beta th
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Similar to beta th
Symptoms are milder
HbA decreased
HbF 5-15%
HbA2 normal
HbLepore
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No normal beta or delta chain
HbF 80-90%
HbA absent
(Homozygous) clinical and
lab.findings are identical to Beta th
HbA2 absent
HbLepore 10%
Beta thalassemia variants
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HbLepore
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HbA decreased
HbA2 decreased
HbLepore 10%
(Heterozygous) clinical and
lab.findings are identical to Beta th minor
Sickle cell anemia
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Qualitative hemoglobinopathy
Valine is substituted instead of glutamine in
the sixth position on the  globin molecule
Sickle cell anemia is caused by homozygosity
for the sickle cell gene and is the most
common form of sickle cell disease
The charge at this site is altered and allows
for polymerization of Hb under conditions of
hypoxia
Sickle cell anemia
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Polymerization of sickle Hb
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distorts erythrocyte morphology
causing a marked reduction in RBC life
span
increases blood viscosity
predisposes to episodes of vasoocclusion
Sickle cell anemiaclinical findings
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Children are normal at birth
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Onset of symptoms is unusual before 3-4 months
of age
High levels of HbF inhibits sickling
Moderately severe hemolytic anemia is often
present by age 1 year
Pallor,fatigue, jaundice
Predispozition to the development of
gallstones
Sickle cell anemiaclinical findings
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Intense congestion of the spleen with sickled
cells may cause
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splenomegaly in early childhood
and results in functional asplenia as early as age 3
months
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Acute splenic sequesteration
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Sudden enlargement of spleen with pooling of red
cells
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Great risk for infection with encapsulated bacteria
Acute exacerbation of anemia, shock, death
Aplastic crisis
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Caused by infection with human parvovirus
Sickle cell anemiaclinical findings
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Vasoocclusive crisis
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Hand-foot syndrome
Abdominal pain
Musculoskletal pain
Stroke
Acute chest syndrome
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Fever, pleuritic chest pain, acute pulmonary
infiltrates
Sickle cell anemialaboratory findings
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Decreased Hb (7-10 g/dl) with normal MCV
Reticulocytosis
Characteristic sickle cells
Hb electrophoresis
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HbS (SCA with 0 th; HbF and S) (sickle +th;HbS
with lesser HbA)
Most infants with sickle hemoglobinopathies
born in USA are now identified by neonatal
screening
Sickle cell anemia-treatment
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Patient and family education
Prevention of complications and
optimization of health
All children should be immunized with
the conjugate pneumococcal vaccine
At the age of 2 months all children
should begin penicillin prophylaxis
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At least at 5 years of age
Sickle cell anemia-treatment
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Treatment of painful vaso-occlusive episodes
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RBC transfusion
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Adequate hydration
Correction of acidosis if present
Administration of analgesics
Maintenance of normal oxygen saturation
Treatment of associated infection
In acute exacerbation
Exchange transfusion
Hydroxyurea
Bone marrow transplantation
Sickle cell trait
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Individuals who are heterozygous for
the sickle gene
Hb electrophoresis
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HbA 60%
HbS 40%
Normal levels of A2 and F
No anemia, no hemolysis
Sickle cell trait
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Exposure to environmental hypoxia may
precipitate splenic infarction or
sequestration
Sudden death during exercise?
Hematuria
Bacteriuria
Intraocular bleeding
Genetic counselling is important
HbE
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Hemoglobinopathy (not a thalassemia)
Production of abnormal globin chains
Beta chain variant in which lysine is
substituted for glutamic acid in position
26
Mild anemia
Reticulocyte count slightly increased
Serum iron, ferritin increased/normal
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The catabolism of 1 gr Hb yields 35 mg
of bilirubin
Red blood cell of the newborn has a
shortened life span= 70-90 days
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Significant bilirubin load
Albumin binding of unconjugated
bilirubin may be important in the
prevention of toxicity (kernicterus)
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In the hypoglycemic infant, glucuronide
production may be limited and thus
conjugation is impaired
The presence of β-glucuronidase in the
bowel lumen during fetal life enables
bilirubin to be reabsorbed and
transported across the placenta for
excretion by the maternal liver
Overproduction of bilirubinHemolytic disease of the newborn
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Blood group incompatibilities such as Rh, ABO
or minor blood groups exist between a
mother and her fetus
Rh(-) mother can become sensitized to the
Rh Antigen
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Improperly matched blood transfusion
Occurance of fetal-maternal blood transfusion
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During pregnancy, delivery, abortion, amniocentesis
Hemolytic disease of the newborn
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Rh antigen
Maternal antibody production
IgG crosses placenta into the fetal circulation
Reacts with the Rh Ag on fetal erythrocytes
These antibody coated cells are recognized as
abnormal and are destroyed by the spleen
Production of bilirubin
Hemolytic disease of the newborn
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Mild hemolysis
Severe anemia, erythroblastosis fetalis
Cardiac decompensation, massive anasarca,
circulatory collapse
Hydrops fetalis (abnormal fluid in two or
more fetal compartments)
The use of anti-D gammaglobulin (rhoGam)
including antenatal administration at 26-28
weeks’ gestation
ABO incompatibility
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ABO incompatibility is limited to
mothers of blood group O and affects
infants of blood group A or B
All group O individuals have naturally
occurring anti-A and anti-B antibodies,
previous sensitization is not necessary
Clinical disease is milder
spherocytosis
poikilocytosis
acanthocytosis
eliptocytosis
stomatocytosis
Fragmentation
hemolysis
Sickle cell anemia;
target cells and sickled
cells
Target cells
Thalassemia; severe
hypochromia
Normal RBC
Heinz body anemia
Anisopoikilocytosis,
target cells
normal
Hypochromic,
microcytes
macrocytes
Target cells
schistocytes