Megaloblastic Megaloblastic AnemiaAnemia

Teoman SOYSAL Prof.MDTeoman SOYSAL Prof.MD

Megaloblastic AnemiaMegaloblastic Anemia

A subclass of macrocytic anemia A subclass of macrocytic anemia

(under morphologic classification)(under morphologic classification)

OrOr A subclass of anemias due to A subclass of anemias due to

defective DNA synthesis defective DNA synthesis

(pathogenetic classification)(pathogenetic classification)

Megaloblastic AnemiaMegaloblastic Anemia

Main causes of “Megaloblastic Main causes of “Megaloblastic Anemia”Anemia”– Vit.B12 deficiencyVit.B12 deficiency– Folic acid deficiencyFolic acid deficiency– OthersOthers

Megaloblastic AnemiaMegaloblastic Anemia

30-50 % of all macrocytic 30-50 % of all macrocytic anemias are caused by folic acid anemias are caused by folic acid and/or Vit.B12 deficiency.and/or Vit.B12 deficiency.

Vit B12Vit B12

Metabolic active cobalamins in the Metabolic active cobalamins in the body are;body are;– Methyl cobalamin and adenosyl cobalaminMethyl cobalamin and adenosyl cobalamin

Hydroxocobalamin can be reversed to Hydroxocobalamin can be reversed to the above cobalamins.the above cobalamins.

Pharmacy:Pharmacy:– Most stable cobalamin: cyanocobalaminMost stable cobalamin: cyanocobalamin

Vit B12Vit B12

Natural formsNatural forms– Produced by microorganisms Produced by microorganisms

(bacteria/fungi)(bacteria/fungi)– Plants do not produce or contain Vit Plants do not produce or contain Vit

B12 (except contamination)B12 (except contamination)– Colonic bacterial production occurs Colonic bacterial production occurs

but their location is distal to the site but their location is distal to the site of absorbtionof absorbtion

Vit.B12Vit.B12

Food sources rich in Vit.B12Food sources rich in Vit.B12 – LiverLiver– KidneyKidney– MuscleMuscle– EggEgg– Milk ,Cheese and other diary Milk ,Cheese and other diary

productsproducts– SeafoodSeafood

Plants are not sources Plants are not sources of Vit.B12of Vit.B12

Vit.BVit.B1212

Daily requirementsDaily requirementsAgeAge Amount/dayAmount/day

0 - 1 0 - 1 0.3 – 0.5 0.3 – 0.5 g, g,

1 – 10 1 – 10 0.7 – 1.5 0.7 – 1.5 g g

AdultsAdults 22g .g .

Pregnancy Pregnancy (2 (2g + ) g + )

22ndnd Trimestr Trimestr 0.50.5gg

33rdrd TrimestrTrimestr 11g g

Lactation Lactation 2.5 – 3 2.5 – 3 gg

Vit.B12Vit.B12

Average diet contains Average diet contains 5 – 305 – 30 g Vit. Bg Vit. B1212 dailydaily

The amount of Vit. BThe amount of Vit. B12 12 in the body is about in the body is about 2 – 52 – 5 mg. mg.

Most of it is in the liver. Most of it is in the liver. The store is sufficient for The store is sufficient for 3-63-6 years in case years in case

of impaired absorbtion.of impaired absorbtion. The storage form is mainly The storage form is mainly

adenosylcobalamin. adenosylcobalamin.

stomach

Enterohepatic circulation

Ileum cells

Pancreas enzymes

Parietal cell

Duodenum and jejunum

B12 in diet R-Binder

R - B12

R- B12

B12 B12

IF B12

TC II

B12

İleum

IF

IF - B12

Vit.BVit.B1212

Circulates with TCII and TCI in plasma.Circulates with TCII and TCI in plasma. Generally in the form of methylcobalamin.Generally in the form of methylcobalamin. Although most of the B12 is bound to Although most of the B12 is bound to

TCI ,TCI , TCII is the functional carrier, rapidly TCII is the functional carrier, rapidly

cleared from plasma.cleared from plasma. TCII deficiency is a cause of megaloblastic TCII deficiency is a cause of megaloblastic

anemia.anemia.

Vit .BVit .B1212

Plazma level of Vit. BPlazma level of Vit. B1212

200 - 900 ng/ L200 - 900 ng/ L

Functions of Vit.BFunctions of Vit.B1212

1)1)

Methylmalonyl co - A mutaseMethylmalonyl co - A mutase

Methylmalonyl co - A succinyl co - AMethylmalonyl co - A succinyl co - A

5-deoxyadenosyl 5-deoxyadenosyl BB1212

Functions of Vit.BFunctions of Vit.B1212

2- 2-

Methyl FHMethyl FH44 FHFH44

HomocysteinHomocystein MethioninMethionin

SAMSAM

BB1122

Methionin synthase

Folic AcidFolic Acid

Pteroyl glutamic acid and similar compounds arePteroyl glutamic acid and similar compounds are

termed as folic acid .termed as folic acid .

Polyglutamate is the Polyglutamate is the natural form.natural form.

Dihydro or tetrahydro folate are Dihydro or tetrahydro folate are metabolic active formsmetabolic active forms..

Folic acidFolic acid

Sources :Sources : Produced by plants and some Produced by plants and some

microorganismsmicroorganisms Folate rich foods;Folate rich foods;

– vegetables (Green leaf), vegetables (Green leaf), – Liver and kidney (parenchymal organs)Liver and kidney (parenchymal organs)

– Molds.Molds.

Folic acidFolic acidDaily requirementsDaily requirements

AgeAge

0 - 10 0 - 10 3.63.6g /kg g /kg > 10 > 10 33g /kgg /kg Pregnants Pregnants 500 500 g g Lactation +100 Lactation +100 g g

Diet contains 100 - 500 Diet contains 100 - 500 g folate/dayg folate/day..

Folate absorbtionFolate absorbtion

Mainly jejunum. Mainly jejunum.

In the form of monoglutamate . In the form of monoglutamate .

Methyltetrahydrofolate monoglutamate Methyltetrahydrofolate monoglutamate is is

the form it is found in serumthe form it is found in serum . .

Folate levels:Folate levels:

Normal rangesNormal ranges Serum:Serum: 6 – 21 6 – 21 g/L g/L (RBC volume) (RBC volume)

Red cell: Red cell: 160 – 640 160 – 640 g/L g/L (RBC volume)(RBC volume)

Folate deficiencyFolate deficiency Serum folate : Serum folate : <4<4g /L g /L Red cell folate: Red cell folate: <140<140g /Lg /L

Folate storesFolate stores

Total body folate:Total body folate: 5 – 20 mg 5 – 20 mg

Storage place :Storage place : LiverLiver

Storage form: Storage form: Methyl-Methyl-FHFH44

polyglutamatepolyglutamate

Functions of folic acid:Functions of folic acid:

Transfer of methyl or formyl groups to otherTransfer of methyl or formyl groups to other compounds. compounds. egeg-During the production of thymidylate for the synthesis of -During the production of thymidylate for the synthesis of

DNA (methylation of deoxyuridylate)DNA (methylation of deoxyuridylate)Source of the 1-carbon moieties;Source of the 1-carbon moieties;1-serine1-serineSerine + THF glycine + N-methylene THFSerine + THF glycine + N-methylene THF

2-Formiminoglutamic acid2-Formiminoglutamic acidFormiminoglutamate+FH4 glutamate+N-formimino THFFormiminoglutamate+FH4 glutamate+N-formimino THF

Dihydrofolate

THFA

Methylene

THFA

Deoxyuridilate Thymidilate DNA-thymine

Methyl THFA

Homocystein

Methyonine

B12

Dihydrofolate reductaseserin

e

glycine

Thymidylate synthase

Megaloblastic HematopoiesisMegaloblastic Hematopoiesis

Anemia +/- leukopenia +/- Anemia +/- leukopenia +/- thrombocytopenia.thrombocytopenia.

Causes of cytopeniasCauses of cytopenias : :

1-DNA synthesis is deranged 1-DNA synthesis is deranged

2-Ineffective hematopoiesis2-Ineffective hematopoiesis

3-Shortened RBC survival3-Shortened RBC survival

Causes of Causes of Megaloblastic AnemiaMegaloblastic Anemia Vit. BVit. B1212 deficiency deficiency Folate deficiencyFolate deficiency Other causesOther causes

Causes of VitBCauses of VitB12 12 deficiencydeficiencyI-Decreased intakeI-Decreased intake

( complete vegetarianism)( complete vegetarianism)

II-Impaired absorbtionII-Impaired absorbtion Gastric causes Gastric causes

( ( Pernicious anemiaPernicious anemia, gastrectomy , caustic injury, Zollinger-Ellison ), gastrectomy , caustic injury, Zollinger-Ellison ) Intestinal causesIntestinal causes

( Ileal resection or disease,eg:sprue,blind loop syndr,Diph.Latum, )( Ileal resection or disease,eg:sprue,blind loop syndr,Diph.Latum, )

Pancreatic disease-(insufficiency) Pancreatic disease-(insufficiency) Familial selective Vit BFamilial selective Vit B1212 absorbtion defect (Imerslund –Grasbeck) absorbtion defect (Imerslund –Grasbeck) DrugsDrugs( PAS, colchicin, neomycine, omeprazol,potasyum chloride,ethanol )( PAS, colchicin, neomycine, omeprazol,potasyum chloride,ethanol )

III-III-Other causesOther causes

Causes of folate Causes of folate deficiencydeficiency

Decreased intakeDecreased intake Increased demandsIncreased demands Drug related folate insufficiencyDrug related folate insufficiency

Causes of Folate Causes of Folate deficiencydeficiency

A) Decreased intake

1-Dietary causes Senility, Alcoholism Hyperalimentation Hemodialysis Prematurity Synthetic diet feeding Goat’s milk feeding

2- Malabsorbtion Nontropical sprue Tropical sprue Intestinal resection Other intestinal diseases

Causes of Folate Causes of Folate DeficiencyDeficiencyB) Increased demands

PregnancyChronic hemolytic diseasesMyeloproliferative diseasesDermatitis(expholiat.)Hyperthyroidism

C) DrugsOral contraseptive drugsSome anticonvulsant drugsTriamtereneCholestyramine

Other causes of megaloblastic Other causes of megaloblastic anemia (1)anemia (1)

I- Combined deficiency of Folate and Vit BI- Combined deficiency of Folate and Vit B12 12 :: Tropical sprueTropical sprue Gluten enteropathyGluten enteropathy

II- Acute megaloblastic anemia:II- Acute megaloblastic anemia: Nitrous oxide anesthesiaNitrous oxide anesthesia Dialysis Dialysis Severe disease + antifolate drug (eg:trimethoprim) Severe disease + antifolate drug (eg:trimethoprim) Total parenteral feedingTotal parenteral feeding

III- Megaloblastic anemia due to drugsIII- Megaloblastic anemia due to drugs Dihydrofolate reductase inhibitors Dihydrofolate reductase inhibitors (eg:MTX,trimethoprim)(eg:MTX,trimethoprim)

Purine antagonists Purine antagonists (eg: 6 MP, azathioprin)(eg: 6 MP, azathioprin)

Pyrimidine antagonists Pyrimidine antagonists ( eg: ARA-C)( eg: ARA-C)

Alkylators Alkylators (eg: cyclophosphamide )(eg: cyclophosphamide )

ZidovudineZidovudine

Other causes of megaloblastic anemia (2)Other causes of megaloblastic anemia (2)

IV- Inherited metabolic diseases:IV- Inherited metabolic diseases: Orotic asiduriaOrotic asiduria Lesch-Nyhan syndromeLesch-Nyhan syndrome Thiamine responsive megaloblastic anemiaThiamine responsive megaloblastic anemia Transcobalamin II deficiencyTranscobalamin II deficiency Homocystinuria , methyl malonic asiduriaHomocystinuria , methyl malonic asiduria Deficiency of enzymes of folate metabolismDeficiency of enzymes of folate metabolism

Methyl tetrahydrofolate transferaseMethyl tetrahydrofolate transferaseFormimino transferaseFormimino transferaseDihydrofolate reductaseDihydrofolate reductase

V- Other: V- Other: Erythroleukemia (?)-not an anemia- alike only Erythroleukemia (?)-not an anemia- alike only

morphologicallymorphologically

Other causes of megaloblastic anemia Other causes of megaloblastic anemia (3)(3)

Clinical features of megaloblastic Clinical features of megaloblastic anemiaanemia

Anemia Atrophic glossitis Neurologic changes

Folic acid deficiency

Vit B12 Deficiency

Tissues or organs other than Tissues or organs other than bone marrow are also affectedbone marrow are also affected

Skin,GIS, female genital system mucosal Skin,GIS, female genital system mucosal epitheliumepithelium

Congenital abn.(neural tube defects)Congenital abn.(neural tube defects) Neurologic changesNeurologic changes(Vit.B(Vit.B1212 deficiency) deficiency)

– Peripheral neuropathyPeripheral neuropathy– Subacute combined degeneration of spinal cordSubacute combined degeneration of spinal cord– Cerebral -Mental changesCerebral -Mental changes

HyperhomocysteinemiaHyperhomocysteinemia

Clinical findings(1)Clinical findings(1) Anemia:Anemia:

Symptoms of anemia + palor+slight icterusSymptoms of anemia + palor+slight icterus

Glossitis :Glossitis :

Sore tongue, poor taste sensation, painSore tongue, poor taste sensation, pain

Papill. atrophy-beefy tonguePapill. atrophy-beefy tongue

Clinical findings(2)Clinical findings(2) Neurologic changes-Vit B12 deficiencyNeurologic changes-Vit B12 deficiency((may occur without anemia)may occur without anemia)

ParesthesiasParesthesiasLoss of position sense, ataxiaLoss of position sense, ataxiaDecreased deep tendon reflexesDecreased deep tendon reflexesMuscle weaknessMuscle weaknessLoss of vibration sense ( post column )Loss of vibration sense ( post column )Spasticity, reflex changes, BabinskySpasticity, reflex changes, Babinsky

(lateral column )(lateral column )RombergRombergMental changes:Memory lossMental changes:Memory loss, confusion, dementia, , confusion, dementia,

hallutination etchallutination etc

Clinical findings(3)Clinical findings(3) Other signs:Other signs:

VitiligoVitiligoHyperpigmentationHyperpigmentationPremature graying of hairPremature graying of hairWeight lossWeight lossFeverFeverDiarheaDiarheaConstipationConstipationMeteorismusMeteorismusSplenomegalySplenomegaly

Peripheral bloodPeripheral blood

CBCCBC::

Anemia Anemia Leukopenia Leukopenia Thrombocytopenia Thrombocytopenia

RBC Indexes:RBC Indexes:

MCVMCV MCHMCH RDWRDW

Peripheral smear(1) :Peripheral smear(1) :

RBC’s RBC’s

Macroovalocytosis ,Macroovalocytosis , Anisocytosis, poikilocytosis , Anisocytosis, poikilocytosis , Bazophilic stippling ,Bazophilic stippling , Howell-Jolly bodies and Cabot ring, Howell-Jolly bodies and Cabot ring, Nucleated red cells Nucleated red cells

Peripheral smear(2) :Peripheral smear(2) :

NeutrophylsNeutrophyls

Neutrophyl hypersegmentation Neutrophyl hypersegmentation

(an early sign of megaloblastic hematopoiesis)(an early sign of megaloblastic hematopoiesis)

Bone marrow findings Bone marrow findings in megaloblastic in megaloblastic anemiaanemia

Bone marrowBone marrow

Hypercellular with erythroid hyperplasia.Hypercellular with erythroid hyperplasia.

Erythroid seriesErythroid series Giant erythroblasts called megaloblastsGiant erythroblasts called megaloblasts Increased numbers of early erythroblastsIncreased numbers of early erythroblasts Nuclear cytoplasmic asynchronismNuclear cytoplasmic asynchronism Increased mytosisIncreased mytosis

Bone marrowBone marrow

Giant metamyelocytes and bandsGiant metamyelocytes and bands

Giant megakaryocytesGiant megakaryocytes

Increased bone marrow iron storesIncreased bone marrow iron stores

Biochemical findingsBiochemical findings

LDHLDH ( LDH -1> LDH - 2)( LDH -1> LDH - 2) Bilirubin(indirect) Bilirubin(indirect) Ferritin and serum iron Ferritin and serum iron Haptoglobin Haptoglobin

Special Lab tests Special Lab tests

1- Vit1- VitBB1212deficiencydeficiency Serum Vit BSerum Vit B1212 Methylmalonic acid Methylmalonic acid

excretion***excretion*** Formiminoglutamate Formiminoglutamate

(FIGlu) excr.(50% cases )(FIGlu) excr.(50% cases ) Radioactive VitBRadioactive VitB12 12

absorbtipon test Deoxyuridine supression Deoxyuridine supression

testtest HyperhomocysteinemiaHyperhomocysteinemia

2-Folate deficiency2-Folate deficiency Serum folateSerum folate(misleads in case of recent folate intake) RBC folate RBC folate (Misleads in cases of Vit B12 deficiency) Formiminoglutamate (FIGlu) Formiminoglutamate (FIGlu)

excretionexcretion Deoxyuridine supression testDeoxyuridine supression test HyperhomocysteinemiaHyperhomocysteinemia

TreatmentTreatment Treat underlying diseaseTreat underlying disease Replacement treatmentReplacement treatment

1- Vit 1- Vit BB1212 deficiency deficiency

cobalamine replacement cobalamine replacement

For 2 weeks: 1000 For 2 weeks: 1000 g / day İMg / day İM

Followed by: Followed by:

1000 1000 g / week until Hb returns to normalg / week until Hb returns to normal

1000 1000 g /mo:life long if g /mo:life long if necessary(eg:pern.anemia)necessary(eg:pern.anemia)

Do not administer folic acid alone to patients with B12 deficiency.Do not administer folic acid alone to patients with B12 deficiency.

Cobalamine replacementCobalamine replacement

Neurologic response is unpredictableNeurologic response is unpredictable BMBM: Megaloblastic changes are lost in 1 - 3 : Megaloblastic changes are lost in 1 - 3

days.days. Reticulocytosis :Reticulocytosis : max:5 – 8 days max:5 – 8 days Hypesegmentation:Hypesegmentation: lost in 1-2 weeks. lost in 1-2 weeks. HbHb:Normalises in 5 – 6 weeks.:Normalises in 5 – 6 weeks. MCV MCV :Normalises in 10 weeks. :Normalises in 10 weeks. Hypokalemia.Hypokalemia.

TreatmentTreatment

2- Folate deficiency2- Folate deficiency Treat underlying conditionTreat underlying condition Folic acid replacement:Folic acid replacement:

Dose :Dose : Start with 1 mg / day ( 2 - 3 weeks )Start with 1 mg / day ( 2 - 3 weeks ) Continue with 0.25 - 0.50 mg / day Continue with 0.25 - 0.50 mg / day Pregnants: 1 mg / dayPregnants: 1 mg / day

Pernicious AnemiaPernicious Anemia

( Addison - Biermer )( Addison - Biermer )

Deficiency of intrinsic factor and Deficiency of intrinsic factor and Megaloblastic anemiaMegaloblastic anemia Athrophic glossitisAthrophic glossitis Neurologic changesNeurologic changes

Types of PA:Types of PA:

Adult: Med: 60 yearsAdult: Med: 60 years Juvenile : 10 - 20 yearsJuvenile : 10 - 20 years Congenital : < 2 yearsCongenital : < 2 years

P.A.P.A.Pathogenesis:

Adult type

Atrophic gastritis:

•Gastric (body)Corpus involved

•All gastric secretions are decresed

•Chief cells and parietal cells are lost and

•intestinal metaplasia may occur.

Congenital type

Selective IF deficiency ( Autosomal res )

Pathogenesis of Gastritis in P.A.Pathogenesis of Gastritis in P.A. Heredity:Heredity:

P.A can be found in the relatives of the patients.P.A can be found in the relatives of the patients. Related to certain HLA antigens ;Related to certain HLA antigens ;

HLA-B7, DW2, DW5, DR2 HLA-B7, DW2, DW5, DR2 Autoimmunity:Autoimmunity: Anti –parietal cell antibodies : 85 %Anti –parietal cell antibodies : 85 % Anti-IF antibodiesAnti-IF antibodies : 55 - 70 % : 55 - 70 % Anti-thyroid antibodiesAnti-thyroid antibodies Other autoimmune diseases and cellular immunityOther autoimmune diseases and cellular immunity

P.A.P.A.

LabLabIn addition to typical blood findings of In addition to typical blood findings of

megaloblastic anemia;megaloblastic anemia; Serum anti-IF antbd***Serum anti-IF antbd*** Serum anti-PC antbdSerum anti-PC antbd Achilia , serum gastrin level increaseAchilia , serum gastrin level increase Gastroscopy and biopsy: atrophic gastitis***Gastroscopy and biopsy: atrophic gastitis*** Schilling’s testSchilling’s test

P.A.P.A.

TreatmentTreatment Life longLife long Cobalamine replacement.Cobalamine replacement.ComplicationComplication Gastric Ca: 2 times normal population Gastric Ca: 2 times normal population