Transcript Red Blood Cell & Bleeding Disorders

Red Blood Cell & Bleeding
Disorders
Normal
Normal Bone Marrow
***
Bone marrow aspirates & Biopsy specimens
Points need to know about
Bone Marrow
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What is it?
Location :
Composition:
How to obtain it?
Why it is done?
Peripheral Blood
Serum
Or
Plasma
Cells
RBC
WBC
Platelets
Peripheral Blood
Serum or plasma
Buffy coat
Hematocrit ( PCV)
or
Red cell volume
Points need to know about
peripheral Blood
• Difference between serum and plasma?
• What is Buffy coat made up of?
• ? Hematocrit or PCV ( packed Cell
Volume)
• How to know the functional status of
marrow by looking at peripheral blood?
Adult Reference Ranges-Red Blood Cells
Measurement (units)
Men
Women
Hemoglobin (gm/dL)
13.6-17.2
12.0-15.0
Hematocrit (%)
39-49
33-43
Red cell count (106/μL)
4.3-5.9
3.5-5.0
Reticulocyte count (%)
0.5-1.5
Mean cell volume (μm3)
MCV
82-96
Mean corpuscular hemoglobin
(pg)
MCH
27-33
Mean corpuscular hemoglobin
concentration (gm/dL) - MCHC
33-37
RBC distribution width
RDW
11.5-14.5
Hematopoiesis
• Origin hematopoietic stem cells unsettled
• Migration of stem cells
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Early months – Yolk Sac
Third month - Liver
Fourth month - Bone marrow
By birth – Marrow is the Sole source of
blood cells
• Up to puberty, entire skeleton - marrow
is red & active
• By age 18 years
– Marrow limited to vertebrae, ribs, sternum,
skull pelvis, and proximal epiphyseal
regions of the humerus and femur
– Remaining marrow yellow, fatty, and
inactive
• Adults - 50% marrow space is active
Clinical significance
Premature infant - Hematopoiesis in liver (rarely
spleen, thymus & lymph nodes )
Extramedullary Hematopoiesis - Abnormal in the fullterm infant
Clinical significance
Stem cell dysfunction
– Marrow failure (***Aplastic anemias)
– Hematopoietic neoplasms (***Leukemias)
Diseases distort the architecture Like
Metastatic cancer, Granulomatous diseases 
 result in abnormal release of immature
precursors into peripheral blood
– “Leukoerythroblastosis”
– Resulting anemia is called as Myelophthesic anemia
Bone Marrow
Morphology
• Bone marrow aspirates
• Biopsy specimens
– Marrow activity - ratio of hematopoietic
elements to fat cells
• Normal - ratio is about 1:1
• Decreased - hypoplasia - Aplastic anemia
• Increased - hematopoiesis - hemolytic anemias,
Leukemias
Bone Marrow
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65% - granulocytes and their precursors;
25% - erythroid precursors
10% - lymphocytes and monocytes & their precursors
Myeloid : Erythroid ratio – 2:1 to 3:1
– Myeloid - myelocytes, metamyelocytes, &
granulocytes
– Erythroid - polychromatophilic &
orthochromic normoblasts
Clinical significance of M:E
Increased: in Myeloid Leukemia
Decreased: in Anemias, *** Polycythemia
Pathology
Red cell disorders
Anemias
↓red cell mass
Polycythemia
↑ red cell mass
Anemias
↓red cell mass
↓
Blood Loss
Hemolytic
↓Erythropiesis
B12, Folate, Iron
Anemias
↓red cell mass
Blood Loss
Acute
Chronic
Blood Loss
• A) Acute Blood Loss
– ***Earliest change in the peripheral
blood -leukocytosis
– Reticulocytosis, reaching 10% to 15%
after 7 days (what is normal count?)
– Early recovery  accompanied by
Thrombocytosis
• B) Chronic Blood Loss
– Regardless of underlying cause -Iron
deficiency anemia (IDA)
Anemias
↓red cell mass
Hemolytic
Membrane defect
HS, PNH
Enzyme defect
G6PD
Defective
Hemoglobin
Synthesis
HbS, Thal,
Immune
Trauma
HEMOLYTIC ANEMIAS
• Based on cause
– Hereditary disorders are due to intrinsic defects
– Acquired disorders to extrinsic factors (like
autoantibodies)
• Based on site of lysis
– Intravascular hemolysis is manifested by
(1) Hemoglobinemia,
(2) Hemoglobinuria,
(3) Jaundice
(4) Hemosiderinuria.
• Decreased serum haptoglobin is characteristic of
intravascular hemolysis.
– Extravascular hemolysis
• Anemia, jaundice, Splenomegaly.
HEMOLYTIC ANEMIAS
• Morphology
– Marrow– Erythroid Hyperplasia increased numbers of
erythroid precursors (normoblasts)
– Extramedullary Hematopoiesis
– Peripheral blood– Reticulocytosis, schistocytes (Fragmented
RBC)
• In chronic cases– Hemosiderosis- why?
– Pigment gallstones (cholelithiasis) – why?
1. Hereditary Spherocytosis (HS)
• Prevalence - Northern Europe
• Genetics - Autosomal dominant (AD) in
three fourths of cases
– The MCC of Autosomal dominant HS - Ankyrin
mutation
– The MC protein deficient in HS - Spectrin
• The most outstanding morphologic finding
- Spherocytes
• Abnormally small, dark-staining (hyperchromic)
• Red cells lacking the normal central zone of pallor
• Not pathognomonic
Hereditary Spherocytosis (HS)
Hereditary Spherocytosis (HS)
Hereditary Spherocytosis (HS)
• Cholelithiasis (pigment stones) occurs in 40% to 50% of
adults.
• Splenomegaly -Moderate (500 to 1000 gm); what is the
normal weight of spleen?
• Clinical Course
• I. characteristic features
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Anemia, Splenomegaly and jaundice
• ii. Aplastic crisis– How you know - sudden worsening of the anemia
accompanied by reticulocytopenia
– Cause -*** parvovirus infection, infects and kills red cell
progenitors
– Lifespan of red cells in HS is shortened to 10 to 20 days,
• iii. Hemolytic crises –
– What you see - increased splenic destruction of red cells
(e.g., infectious mononucleosis);
Hereditary Spherocytosis (HS)
• Diagnosis of HS –
– Family history,
– Hematological findings,
– Laboratory evidence
• Osmotic lysis,
– ↑ mean cell hemoglobin concentration
(MCHC)
• Rx: - splenectomy is often
beneficial
2. Paroxysmal Nocturnal
Hemoglobinuria
• Only hemolytic anemia caused by an
acquired intrinsic defect in the cell
membrane
• results from acquired (somatic)
mutations in phosphatidylinositol glycan A
(PIGA) - essential for the synthesis of the
GPI anchor
• GPI-linked proteins inactivate
complement (mutations of these proteins 
uncontrolled complement activation)
• complement mediated lysis of Red cells,
white cells, and platelets
Paroxysmal Nocturnal
Hemoglobinuria
• Three GPI-linked proteins mutated
/ deficient in PNH
– decay-accelerating factor (DAF) or
CD55;
– membrane inhibitor of reactive lysis, or
CD59; (is the most important in PNH)
– C8 binding protein
Paroxysmal Nocturnal
Hemoglobinuria
Clinical manifestations
• Venous thrombosis, (hepatic, portal, or
cerebral veins-fatal in 50% of cases)
– prothrombotic state is due to
Dysfunction of platelets
• ↑risk of acute myelogenous leukemia
(AML)
Rx. immunosuppression
3. Glucose-6-Phosphate
Dehydrogenase Deficiency
• Basic defect
– Inability of red cells to protect themselves
against ***oxidative injuries
– Leading to hemolytic disease
– Abnormalities in the hexose
monophosphate shunt or glutathione
metabolism
Glucose-6-Phosphate Dehydrogenase
Deficiency
• Variants
– G6PD B Normal variant
– G6PD A- 10% of African Americans
– G6PD Mediterranean-clinically
significant hemolytic anemias
• Protective effect against Plasmodium
falciparum malaria
• X- Linked recessive
– Males at highest risk
Glucose-6-Phosphate
Dehydrogenase Deficiency
Clinical patterns1. Foods- fava beans (favism),
2. Medications - ***antimalarials (e.g.,
primaquine and chloroquine),
sulfonamides, nitrofurantoins,
3. Infections- viral hepatitis, pneumonia,
and typhoid fever
Hemolysis causes both intravascular and
Extravascular lysis
• after exposure to oxidant stress
Glucose-6-Phosphate
Dehydrogenase Deficiency
Lab• Peripheral blood
– Heinz bodies. -denatured Hb (RBC
stained with crystal violet)
– "bite cells"
– Spherocytes
Glucose-6-Phosphate
Dehydrogenase Deficiency
Features of chronic hemolytic anemias
(splenomegaly, cholelithiasis)
are absent
4. Sickle Cell Disease
Basic defect
• production of defective hemoglobinshereditary hemoglobinopathy
• sickle hemoglobin (HbS) -point
***(splicing) mutation at the sixth
position of the β-globin chain
• substitution of a valine residue for a
glutamic acid residue
Sickle Cell Disease
• Incidence
– 8% of black Americans are
heterozygous for HbS- (40% of the
hemoglobin is HbS)
– In Africa, 30% of the native population
are heterozygous.
• Advantages
– Protection against falciparum malaria
Sickle Cell Disease
• Mechanism of Sickling
– deoxygenated, HbS molecules undergo
aggregation and polymerization
– Sickling-initially a reversible
– precipitation of HbS fibers also causes
oxidant damage, not only in irreversibly
sickled cells but also in normal-appearing
cells
– sickle red cells - abnormally sticky
Sickle Cell Disease
• Most important factors affect the rate and degree
of Sickling
– Promotes Sickling
• Amount of HbS
• HbC
• Decrease in pH
• intracellular dehydration
• length of time red cells are exposed to low oxygen tension
(spleen and the bone marrow microvascular beds )
– Inhibit Sickling
• Co-exists α- Thalassemia
• HbA & HbF
Sickle Cell Disease
• Pathogenesis of microvascular
occlusions
– reversibly sickled cells express higher
than normal levels of adhesion
molecules and appear abnormally
sticky in certain assays
– plasma hemoglobin (released from
lysed RBC) binds to and inactivates
NO
Sickle Cell Disease
• Morphology.
• Expansion of the marrow
– prominent cheekbones
– skull X-ray- crew-cut appearance
• children during early phase -splenomegaly
• adolescence / adulthood -autosplenectomy
• Infarction also seen in bones, brain, kidney,
liver, retina, and pulmonary vessels
(producing cor pulmonale - ?)
• leg ulcers in adult patients (rare in children)
• pigment gallstones
Sickle Cell Disease
• Clinical Course
• infection with encapsulated organisms, pneumococci and Haemophilus influenzae
– Septicemia and meningitis -MCC of death in
children
• Vaso-occlusive crises- also called pain crises (MCC
of morbidity and mortality)
– episodes of hypoxic injury and infarction (MC sites
- bones, lungs, liver, brain, spleen, and penis)
– In children, painful bone crises
• extremely common
• DD- acute osteomyelitis
– hand-foot syndrome
– acute chest syndrome
• slow pulmonary blood flow
• "spleenlike," lungs
Sickle Cell Disease
• Aplastic crises- parvovirus B19
• Sequestration crises - children with
intact spleens
• Chronic tissue hypoxia
– Renal medulla
• hyposthenuria (inability to concentrate
urine)
• ↑ propensity for dehydration and its
attendant risks
• Diagnosis
– Suggested by -sickle cells in peripheral blood
smears
– Confirmed by -Hemoglobin electrophoresis
Sickle Cell Disease
• Prenatal diagnosis
– amniocentesis or chorionic biopsy
• Rx. Hydroxyurea
• increase in the concentration of HbF
• anti-inflammatory agent by inhibiting the
production of white cells
• increases the mean red cell volume
• oxidized by heme groups to produce NO
• reduce pain crises in children and adults
5.Thalassemia Syndromes
Genetic disorders leading to decreased
synthesis of either the α- or β- globin
chain of HbA
• hematologic consequences are due to
– low intracellular hemoglobin 
hypochromia
– relative excess of unimpaired chain
membrane damage
Thalassemia Syndromes
β-Thalassemias
• ↓synthesis of β-globin chains
• Molecular Pathogenesis
– Adult hemoglobin (HbA) –tetramer of two
α chains and two β chains
– pair of α-globin genes on chromosome 16
– single β-globin gene on chromosome 11
– β0-thalassemia- total absence of β-globin
chains in the homozygous state
– β+-thalassemia- reduced (but detectable)
β-globin synthesis
Thalassemia Syndromes
β-Thalassemias
• Most are point mutations (unlike α-thalassemia
- deletions )
• MC mutations- Splicing mutations Anemia mechanisms
– Free α chains precipitate
– Form insoluble inclusions& inclusions cause cell
membrane damage
1. normoblasts in the marrow undergo apoptosis
(ineffective Erythropoiesis)
2. inclusion-bearing red cells escape marrow 
splenic sequestration
both 1 & 2 lead to ?
Thalassemia Syndromes
β-Thalassemias
• ↑Erythropoietin secretion -expanding
mass of erythropoietic marrow
– impairs bone growth  skeletal
abnormalities
– Extramedullary hematopoiesis (liver,
spleen, and lymph nodes)
– excessive absorption of dietary iron
secondary hemochromatosis
Thalassemia Syndromes
β-Thalassemias
Clinical Syndromes
1. Thalassemia Major
– most common in Mediterranean
countries (Africa and Southeast Asia)
– In USA, highest in immigrants
– Anemia manifests 6 to 9 months after
birth, (Hb synthesis switches from HbF
to HbA)
• Hemoglobin-3 and 6 gm/dL.
Thalassemia Syndromes
β-Thalassemias
1. Thalassemia Major
peripheral blood smear
• marked anisocytosis and poikilocytosis
• microcytosis (small size), and
hypochromia
• Target cells
• basophilic stippling
• fragmented RBC (Schistocytes)
• Reticulocytosis
• Normoblasts (nucleated RBC)
Thalassemia Syndromes
β-Thalassemias
1. Thalassemia Major
• HbF - markedly increased (major red cell
hemoglobin)
• Morphology
– major morphologic -expansion of
hematopoietically active marrow, facial bones.
– "crew-cut" appearance - skull X-rays
– Splenomegaly ( up to 1500 gm)
– Hemosiderosis and secondary Hemochromatosis
Thalassemia Syndromes
β-Thalassemias
1. Thalassemia Major
• Clinical course
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Untreated children-growth retardation,
die of anemia
With Cardiac disease -important cause
of death (due to iron load)
Only curative therapy -Bone marrow
transplantation
• Prenatal diagnosis – possible
Thalassemia Syndromes
β-Thalassemias
• Thalassemia Minor
– much more common than thalassemia major offer resistance against falciparum malaria
• peripheral blood
– hypochromia, microcytosis, basophilic stippling,
and target cells
– bone marrow-Mild erythroid hyperplasia
• best confirmatory test -Hemoglobin
electrophoresis
– HbF - normal or slightly increased
– HbA2 - 4% to 8% of the total hemoglobin (normal
HbA2:- 2.5% ± 0.3%)
Thalassemia Syndromes
α-Thalassemias
• normally four α-globin genes
• severity varies with the number of αglobin genes affected
• free β and γ chains are more soluble
than free α chains
Thalassemia Syndromes
α-Thalassemias
1. Silent Carrier State
– single α-globin gene is deleted
– insufficient to result in anemia
– completely asymptomatic
2. α-Thalassemia Trait
– deletion of two α-globin genes
– clinical picture identical to β-thalassemia
minor
– small red cells (microcytosis), minimal or
no anemia, and no abnormal physical
signs
Thalassemia Syndromes
α-Thalassemias
3. Hemoglobin H Disease
– mostly in Asian populations (rarely in African )
– only one normal α-globin gene
– moderately severe anemia
4. Hydrops Fetalis
– most severe form of α-thalassemia
– deletion of all four α-globin genes
– evident by- third trimester of pregnancy
– excess γ-globin chains form tetramers
(hemoglobin Barts) has high affinity for oxygen
& no oxygen to tissues
– fetus - severe pallor, generalized edema, and
massive Hepatosplenomegaly (similar to in
erythroblastosis fetalis)
What is this?
6. Immunohemolytic Anemia
• Causes - extra corpuscular mechanisms
• Diagnosis - Coombs antiglobulin test.
1. Warm Antibody Immunohemolytic Anemia
– the most common form (48% to 70%) of immune
hemolytic anemia
– 50% of cases are idiopathic (primary)
– Most causative antibodies are of the
immunoglobulin G (IgG) class
– antibodies - against Rh blood group antigens
– Antigens- penicillin and cephalosporins &
Quinidine, α-methyldopa
Immunohemolytic Anemia
2. Cold Agglutinin Immunohemolytic
Anemia
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–
IgM antibodies
Causes:
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Acute - certain infectious disorders Mycoplasma , infectious mononucleosis ,
cytomegalovirus, influenza virus, HIV
Chronic -with certain lymphoid neoplasms or
idiopathic
Clinical symptoms - pallor, cyanosis of the
body parts (Raynaud phenomenon) of
exposed to below 30°C temp. (fingers, toes,
and ears )
Immunohemolytic Anemia
3. Cold Hemolysin Hemolytic Anemia
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Also called paroxysmal cold hemoglobinuria
intravascular hemolysis - with hemoglobinuria,
after exposure to cold temperatures
complement dependent
IgGs (Ab) - bind to P blood group antigen on
the red cell surface at low temperatures
Donath-Landsteiner antibody
Mycoplasma pneumonia, measles, mumps, and
ill-defined viral and "flu" syndromes.
first recognized with syphilis
Hemolytic Anemia Resulting from
Trauma to Red Cells
1.cardiac valve prostheses (artificial
mechanical valves )
2. narrowing or obstruction of the
microvasculature
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Microangiopathic hemolytic anemia (MCC is
DIC)
Other causes -malignant HTN, SLE, TTP, HUS,
disseminated cancer
common feature -mechanicalRBC injury
Schistocytes , "burr cells," "helmet cells,"
and "triangle cells"
Anemias
↓red cell mass
↓Erythropiesis
Megaloblastic
B12,Folate,
Iron deficiency
Anemia of Chronic
disease
Aplastic anemia
Pure red cell aplasia
Others
Red cell disorders
Anemias
↓red cell mass
Polycythemia
↑ red cell mass
Secondary/Reactive
Primary
/Idiopathic/Vera
Bleeding disorders
Vascular
abnormalities
Platelet disorders
Clotting factor
abnormalities
DIC
Bleeding disorders
Platelet disorders
↓production
↑destruction
Primary/Idiopathic
ITP
Sequestration
Hypersplenism
Secondary