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Causes of megaloblastic anaemia
1. Folic acid deficiency
a. Inadequate diet
b. Alcoholism
c. Steatorrhea or sprue
d. Other causes of malabsorption, including partial gastrectomy
e. Pregnancy and lactation
f. Leukaemia, myelofibrosis, and chronic haemolytic anaemia
2. Vitamin B12 deficiencya. Pernicious anaemia
b. Gastrectomy
c. Sprue
d. Long-term dietary deficiency
e. Parasites (Diphyllobothrium latum
3. Drug induced megaloblastic anaemia
4. Congenital disorders (very rare)
5. Leukaemia
6. Di Guglielmos syndrome
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Source of folic acid
> Green vegetables, liver, yeast
> Destroyed by prolonged boiling & acid pH
Source of vitamin B12
> Synthesized by bacteria form large bowel
> Liver & kidney
> Dairy products, fish, shellfish
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LABORATORY DIAGNOSIS OF MACROCYTIC ANAEMIA
LABORATORY TEST INTERPRETATIONPeripheral smear
Bone marrowexamination
Reticulocyte count
Therapeutic response
Diagnosis
Macrocytic anaemia
Megaloblasticchanges No megaloblasticchanges
Low LowHigh
Possible
liver disease
Probable
haemolytic
anaemia
Responds tofolic acid
Respondsto vit B12
Vit. B12
deficiency
Folic acid
deficiency
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Terminal ileum Blood Tissue cells
Absorption of Vit. B12 Absorption of Vit. B12and folate
ABSORPTIONOFFOLIC ACID AND VIT. B12
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A Normal Healthy Individual
PGA
Vit.B12
Poly
glutamateis
stor
edinRBCs
Normal Red Blood Cell
Polyglutamate
(RBC folate)
DNA
5-m-THF(Serum Folate)
THF
LAB RESULTS FOR
NORMAL HEALTHY PERSON
Serum Folate Normal
RBC Folate Normal
Serum Vit. B12 Normal
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Folate Deficiency
Polyglu
tamateis
stored
inRBCs
islow
PGA
Normal
Vit.B12
Low THF
Low
Polyglutamate
(RBC folate)
Low DNA
Macrocytic Cells
Low 5-m-THF
(Serum Folate)
LAB RESULTS FOR FOLATE
DEFICIENCY
Serum Folate Low
RBC Folate Low
Serum B12 Normal
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Vit. B12 deficiency
PGA
Normal or High 5-m-THF
(Serum Folate)Low
Vit.B12
Low THF
Low or Normal
Polyglutamate
(RBC folate)
Low DNA
Macrocytic Cells
Polyglutamateis
storedinRBCs
islow
LAB RESULTS FOR Vit. B12DEFICIENCY
Serum Folate Normal or High
RBC Folate Low or Normal
Serum B12 Low
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Vit.B12 and Folate Deficiency
PGA
Low 5mTHF(Serum Folate)Low
Vit.B12
Low THF
Low
Polyglutamate
(RBC folate)
Low DNA
Macrocytic Cells
Polyglutamateis
stored
inRBCs
islow
As with folate or Vit.B12
deficiency,
the RBCs are macrocytic
With low Vit.B12 and low folate present,5-m-THF is not converted to THF
LAB RESULTS FOR
Vit.B12 and FOLATE DEFICIENCY
Serum Folate Low
RBC Folate Low
Serum Vit.B12 Low
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Deficiency Folic acid Serum
vit. B12
Serum RBC
Folic acid
Vit B12
Folic acid & B12
N /N
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THERAPEUTIC TRIALS
Usual diet
0,2 mg folic acid
oral
1 week
reticulocyte response
+ -
+ 1 - 2 mg Vit. B12reticulocyte response
Contraindications :
- patients on critical ill
- angina pectoris
- congestive heart disease
- thrombocytopenia with bleeding
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GENETIC DEFECTS OF HAEMOGLOBIN
(Haemoglobinopathy)
Reduced or abnormal synthesis of normal globin
Reduced Thalassaemia
Abnormal Hb - abnormalities
Hb varian
Fraction of normal haemoglobin in :
adult full-term infant
HbA2 < 3.5% < 1%
HbF < 1.0% 50 - 85%
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Occur in tropical = sub tropical area
Protection against Falciparum malaria
The geographycal distribution of thethlassaemia and haemoglobin abnormalities
Mediterania,
Afrika,
Timur Tengah,
India,
Burma,
Asia Tenggarameliputi :
China selatan,
Malaysia
Indonesia
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CLASSIFICATION
CLINICAL- Thalassaemia major
- Thalassaemia intermedia
- Thalassaemia minor
- Silent carrier
GENETIC
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The globin gene clusters on chromosom 16 and 11 in embrionic, foetal and adult
Prenatal age (weeks) Postnatal age (weeks)
Synthesis of individual globin chain in prenatal and postnatal life
PATHOPHYSIOLOGIC
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PATHOPHYSIOLOGIC a-THALASSAEMIAb chain2 genes
a chain4 genes
g chain2 genes
Child and adultFoetus and neonates
g4Hb Barts
a2 g2HbF
a2 b2HbA
b4HbH
Thalassaemia-aInclusion HbH
Hydrops foetalis HbH disease
Heinz bodiesprecipitation
DEATH
Bone marrow
IneffectiveErythropoiesis
Organ dysfunction
Peripheral blood
Iron overload
MICROCYTIC HYPOCHROMICANAEMIA
Iron
absorption
MultipleTransfusion
Increased erythropoiesis
Intramedullary ExtramedullaryBone changes Hepatosplenomegaly
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1. HYDROPS FETALIS
-- / --
4 gen deletion
Suppress a chain synthesis
Failure of HbF synthesis
Death in utero
(Hydrop fetalis)
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Laboratory
Hb 3 - 10 g/dL
MCV 110 - 119 fl,
MCH
Anisocytosis, poikilocytosis
Retikulocytosis, NRBC +++
Electrophoresis : Hb Barts (g4) 80-90%Hb Portland +
Hb A absent
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a thalassaemia : four a gene deletion(hydrops foetalis)
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2. HbH DISEASE
3 genes deletion
HbH (b4), unstable, termolabile Clinic :
Normal birth
Anaemia after one year
Hepatosplenomegaly & icterus
HbH diseaseHbH inclusion bodiesHaemoglobin electrophoresis
Normal
HbHb thal. HbENormal
b thal. traitb thal. trait
2 HbH DISEASE
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2. HbH DISEASE
Laboratory
1. Hb 8-10 g/dL
Microcytic hypochromic anaemia
Target cells ++, NRBC +, poikilocytosis andanisocytosis
2. Reticulocytosis, HbH inclusion bodies +++
3. Hb electrophoresis
adult neonates
Hb Barts 25%
HbH 2-40%
HbA2
HbF
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HbH maybe found in
1. a thalassaemia : HbH disease, a thal 1 trait2. Myeloproliferative disorders ALL, AML &
sideroblastic anaemia
Defect a gene transcription
Deficiency a RNA
Deficiency a chain
HbH (5-70%)
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3. a THALASSAEMIA 1 TRAIT (MINOR) 2 genes deletion
a- / a- homozygous a thal 2-- / aa heterozygous a thal 1
Clinic : none
Laboratory :
1. Hb 10 - 12 g/dL
Microcytic hypochromic anaemia
VER 60 - 70 fl
HER 20 - 25 pg
Anisocytosis
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3. a THALASSAEMIA 1 TRAIT (MINOR) Laboratory
2. Hb electrophoresis Cord blood : Hb Bart 5-6%
after 1-3 month
Hb Bart 0%
Adult :
Microcytic hypochromic without anaemia
Ferritin N /
Electrophoresis Hb : Hb Bart 0%
HbH inclusion bodies 1/1000 1/10.000
RBC
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4. a THALASSAEMIA 2 TRAIT (SILENT CARRIER) -a / aa Clinic : normal
Laboratory
Cord blood : HbH < 1%
PATHOPHYSIOLOGIC -THALASSAEMIA
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PATHOPHYSIOLOGIC b-THALASSAEMIA
d chain(2 genes)
g chain(2 genes)
b chain(2 genes)
a chain (4 genes)Child and adultFoetus and neonates
b Thalassaemia major
HbF
a2 g2HbA
a2 b2b Thalassaemia minor
HbA2a2 d2HbA
a2 b2HbF
a2 g2
Heinz bodies
Bone marrow
Ineffective Erythropoiesis
MICROCYTIC HYPOCHROMIC
MICROCYTIC HYPOCHROMIC
ANAEMIA
Iron absorption
Transfusion
Increased erythropoiesis
Intramedullary haematopoiesis Extramedullary haematopoiesis
Bone changes Haepatomegaly Splenomegaly
Hipersplenism
Iron overload
ORGAN DYSFUNCTION
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homozygote b thalassaemia(major) post splenectomy
homozygote b thalassaemia(major)
heterozygote b thalassaemia(minor)
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b Thlassaemia majorClinic :
Severe anaemia becomes apparent at 3 - 6month after birth
Hepatomegaly
Splenomegaly (increased RBC destruction inpooling), expansion the plasma volume
Expansion of bone (thalassaemic facies)
Iron overload (endocrine organs &myocardium)
Pneumococcal & meningococcal, hepatitis B,
hepatitis C, HIV infection
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b Thlassaemia majorLaboratory :
Microcytic hypochromic anaemia,reticulocyte (%), normoblasts, target cells &
basophilic stippling
Haemoglobin electrophoresis :HbA2 normal, or
HbF
HbA absence or almost complete absent Ferritin 1000 - 1500 mg/L
Ferritin is raised in viral hepatitis & inflamatory
disorders
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Mongoloid facies Hair on end appearance
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b thalassaemia trait (minor)Clinic :
Symptomless abnormality
Laboratory : Mild or no anaemia (Hb 10-15 g/dL)
RBC microcytic hypochromic
Haemoglobin electrophoresis :HbA2 > 3.5%
HbF N /
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