Presentation on theme: "MACROCYTIC ANEMIAS Ahmad Sh"— Presentation transcript:
1 MACROCYTIC ANEMIAS Ahmad Sh MACROCYTIC ANEMIAS Ahmad Sh. Silmi Staff Specialist in Haematology Medical Laboratory Sciences Dept, IUG 2012
2 Introduction Anemia classification based on the mechanism Kinetic Classification (based on retic count)Decreased productionMorpholgical classification (based on MCV)MicrocyticNormocyticMacrocyticIncreased destructionImmunological classification (based on Coomb’s test)Immune-mediatedNon-immune mediated
3 The Medical Student’s Approach to Anemia Check the reticulocyte count to determine if the anemia is from decreased production (“hypoproliferative”, “reticulocytopenic”) or increased destruction (“hemolytic”)/acute blood loss (“reticulocytosis”)2. If decreased production, narrow down the causes in terms of the MCV-If the MCV is low, then do iron studies then Hb electropheresisIf the MCV is normal, check the serum creatinine and TSH, if they are WNL then consider bone marrow examIf the MCV is high check a folate and vitamin B12 level3. If the reticulocyte count is increased-Check a direct Coomb’s test4. Look at the peripheral blood smear to confirm/support the diagnosis
5 Renal vs. Liver vs. Endocrine vs. Anemia of Inflammation Anemia AlgorithmPatient with anemia and decreased reticulocyte count-What is the MCV ??MicrocyticNormocyticMacrocytic:Vitamin-relatedB12, FolateNon-vitamin:MDSEtOH/Liver DiseaseHypothyroidismDiseases in Bone MarrowMDSSolid TumorMyelomaAplastic anemiaFedef.Systemic DiseasesThalRenal vs. Liver vs. Endocrine vs Anemia of InflammationOther: sideroblastic anemia
7 Requirements for Red Blood Cell Production ErythropoeitinProteins, required for globin synthesisIronVitamin B12 and folic acidVitamin B6Vitamin CThyroid hormones, estrogens and androgens
8 Definitions Macrocytic MCV > 100MCH is increased due to increased cell sizeMCHC is normal as concentration of hemoglobin is normalMacrocytosis is found in 2.5-4% of adults having a routine CBCSub classificationMegaloblasticNon-megaloblastic
9 Macrocytic anemias Megaloblastic Non-Megaloblastic More severe macrocytosis with oval erythrocytesUsually MCV is >110Defects in DNA syntheses leading to delayed nuclear development in the face of normal cytoplasmic developmentMarrow shows nuclear cytoplasmic asynchronyErythroid lineageMyeloid lineageReticulocyte index is not increasedNon-MegaloblasticLess severe macrocytosis with round erythrocytesUsually MCV is <110Pathophysiology unknownIncrease in membrane lipidsImmature cells (reticulocytes) are increased
10 Macrocytic anemias * * * Megaloblastic Non-Megaloblastic B 12 deficiencyFolate deficiencyDrugsMegaloblastoid morphologic changes can be seen inMyelodysplastic syndromesCongenital dyserythropoietic anemiasNon-MegaloblasticAlcoholismLiver diseaseHypothyroidismAplastic anemiaHemolysis, acute bleedIncreased reticulocytes and immature erythrocytesArtifactRBC clumpingcold agglutinin diseaseHyperglycemiaRBC swelling***
11 MEGALOBLASTIC ANEMIAThese are a group of disorders in which the cause the anemia is due to deficiency of vitamin B12 and folic acidThe macrocytes in this condition is usually “oval” - hence they are also called as MACRO OVALOCYTES
12 NON MEGALOBLASTIC MACROCYTIC ANEMIAS These are disorders in which the macrocytosis is not due to vitamin B12 or folic acid deficiencyHere the macrocytes are “ROUND”The conditions in which such round macrocytes are seen areReticulocytosisHypothyroidism / myxedemaMyelodysplastic syndromeScurvy (Vit-C dif)Sideroblastic anemiaLiver disorders
13 MEGALOBLASTIC ANEMIAVitamin B12 and folic acid are important nutrients required in the process of nuclear maturationThey are required during erythropoiesis (during DNA synthesis)These anemias may be caused because of a nutritional deficiency or impaired absorption mainly.
14 MEGALOBLASTIC ANEMIAImpaired DNA synthesis leading to defective cell maturation and cell divisionNuclear maturation delays from the cytoplasmic maturation – NUCLEAR CYTOPLASMIC ASYNCHRONYAbnormally large erythroid precursors and red cells
15 Folic Acid: Daily requirement: Transportation: It a vitamin which is yellow in colour, water soluble, necessary for the production of the RBC, WBC and platelets.It is not synthesized in the body.It is found in large number of green fresh vegetables, fruits.Daily requirement:The human body needs about µg daily. Absorption:It is absorbed in the Duodenum and Jejunum.Transportation:Weakly bound to albumin.
16 METABOLIC FUNCTION Purine synthesis Conversion of homocysteine to methionine ( which also requires B12 )
19 INCREASED DEMAND Pregnancy Lactation Infancy Puberty and growth period Patients with chronic hemolytic anemiasDisseminated cancer
20 DECREASED INTAKE Elderly Lower socio economic status Chronic alcoholics
21 DECREASED ABSORPTIONAcidic food substances in foods like legumes, beansDrugs like phenytoin, oral contraceptivesCeliac disease which affect the gut absorptionHeat sensitive – more loss during cooking
23 Vitamin B12:This vitamin is synthesized in nature by micro-organism in the intestine of man and animals, but we can not obtain it from the bacteria in our bodies, because it is synthesizing in the large colon after the site of absorption and it is wasted in the faeces in about 5µg/day. So we obtain it from animal food such as liver, kidney, meat and dairy products as milk and cheese.
24 VITAMIN B12 Abundant in animal foods Microorganisms are the ultimate origin of cobalaminIt is stored in liver for many yearsIt is efficiently reabsorbed from bileIt is resistant to cooking and boiling
25 Diary requirements:The human body needs about 1-2 µg daily.Absorption:B12 is combined with glycoprotein called the intrinsic factor (IF), which is synthesized in the gastric cells. The absorption occurs in the distal ileum.Transportation:Transport by a protein synthesized in the liver called Transcobalamine II, which carry vitamin B12 to liver, nerves and bone marrow.
29 IMPAIRED ABSORPTIONINTRINSIC FACTOR DEFICIENCY due to chronic gastritis or antibodies against stomach cells.- PERNICIOUS ANEMIA- GASTRECTOMYMalabsorption statesDiffuse intestinal diseases. Eg., lymphoma, systemic sclerosisCompetitive parasitic uptake – fish tapewormBacterial overgrowth
30 Pathophysiology Folates are compounds derived from folic acid that are involved in numerous metabolic reactionsGenerally folates act as donor of single carbon groupsdUMP=deoxyuridylate monophosphateDTMP=deoxythymidylate monophosphateOne such reaction is thymidylate synthesisDefective thymidylate synthesis leads to defective DNA synthesisMegaloblastic anemia
31 B12 and folate B12 is a known cofactor in 2 enzymatic reactions (1) B12 is a cofactor of methionine synthase which is required to regenerate folate within the cell
32 Other sequelae of B12 deficiency (2) Conversion of methylmalonyl CoA and finally to succinyl-CoACo factor for methylmalonyl CoAFailure of this pathway leads to abnormalities in neuronal membrane synthesis.Also, methionine is a precursor for S-adenosylmethionine-a metabolite critical for normal function of the nervous system.Neurologic defects seen with B12 deficiencyPeripheral neuropathyDisturbances of vibratory sense and proprioceptionDorsal and lateral column demyelinationSpastic ataxiaBrainDementia, psychosis, somnolenceAlthough anemia may respond to folate therapy, neurologic findings will notNeurologic findings may be permanent if not treated early1Up-to-Date
33 Folate deficiency Dietary sources Metabolism Present in animal and vegetable productsAsparagus, broccoli, spinach, lettuce, lima beans (>1mg/100g dry weight)Liver, yeast, mushrooms, orangesCooking depletes food of folateMetabolismAbsorbed most actively in the jejunum and upper ileumBody stores are 5-10 mg (liver)Minimal daily intake is 50 microgramsHigher for pregnancy and lactationFolate deficiency can lead to birth defects (neural tube defects)If intake is reduced to 5 micrograms/day, megaloblastic anemia will develop in ~4 months
34 Folate deficiency Causes of folate deficiency Decreased intake (most common)Dietary deficiencyInfants on a Goat’s milk dietSmall intestinal diseaseTropical sprueCeliac sprue (gluten sensitive enteropathy)Increased requirementPregnancyAlcoholismHemolytic anemiaLeukemia
35 B12 deficiency Dietary sources Metabolism Animal products (meat and dairy)MetabolismIngested B12 is protein boundTrypsin and acid in stomach release B12B12 binds R-binding protein which carries it to the jejunumAlso in the stomach (fundus and body) intrinsic factor is secreted.In the jejunum, pepsin releases B12 from R-binding proteinB12 binds intrinsic factor and is carried to the ileumB12 is absorbed in the ileumBody stores 2-5mg (mostly in the liver)Need 3-5 micrograms per day for maintenance of storesIncreased need in pregnancy, lactation, growthDepletion takes longer that folateIt takes years to develop megaloblastic anemia due to B12 deficiency
37 Diagnosis Clinical findings Morphology-peripheral blood and marrow Megaloblastoid morphologic changesFolate deficiencyFolate, serum levelReflects recent levels of ingestionFalsely increased with hemolysisRBC FolateReflects stores (2-3 months)Will be decreased in B12 deficiencyB12 deficiencyFolate levels are decreased in B12 deficiency, should check both in tandemB12, serum levelSerum methylmalonic acid and homocystine levels may be more sensitiveB12 deficiency, both are elevatedsensitivity 94%, specificity 99%Folate deficiency, only homocystine levels are elevatedMay miss 10-26% of patients with serum B12 levels aloneSchillings testHelps to identify the source of B12 deficiencyHomocystineMMA
38 Sequence of changes in megaloblastic anemia Vitamin levels decreaseNeutrophil hypersegmentationOval macrocytosis in the peripheral bloodMegaloblastic changes in the marrowAnemia
39 MEGALOPLASTIC ANAEMIA. Affect all marrow elements.Neurologic symptoms (dorsal columns)Ineffective erythropoiesis: High indirect bilirubin Very high LDH
40 Ineffective hematopoiesis Because of the faulty megaloblastic maturation seen in the marrow, cells die during cell divisionHypercellular marrow due to erythroid hyperplasia with increased red blood cell precursors in the marrow but a macrocytic anemia in the peripheryRelease of cell constituentsIncreased bilirubinIncreased LDH
41 CLINICAL FEATURESPatients develop all general symptoms and signs of the anaemia.Knuckle pigmentationAngular stomatitisAtrophic glossitis- “beefy” tongueNeurological disorders: sever deficiency of the folic acid causes neuropathies diseases.Deficiency during pregnancy causes neural tube defect.
43 Schillings test Allows one to determine the level at which B12 deficiency is occurringDietary deficiencyMalabsorptionAbsence of intrinsic factor
44 Screening hematology laboratory tests for megaloblastic anemia CBCMacrocytic anemiaMCV is usually >110 fL and often >120 fLPancytopenia is seen in some casesPeripheral blood morphologyOval macrocytesNucleated RBCs, Howell Jolly bodies, basophilic stippling, Cabot ringsNeutrophil nuclear hypersegmentationfive 5 lobed neutrophils per 100 WBCOne six lobed neutrophil
45 Megaloblastic anemia: Morphology--Blood MegaloblastoidNormalPeripheral bloodMacro-ovalocytesNeutrophil nuclear hypersegmentationVery sensitive and specific
46 Howell Jolly body. - Round, dark, refractile RBC inclusion Howell Jolly body - Round, dark, refractile RBC inclusion - Nuclear remnant - Most commonly seen in hyposplenismBasophilic stippling - Multiple small blue dots dispersed regularly throughout the RBC - RNA complexesCabot ring - Ring shaped, thin - May be figure of 8 shaped - Microtubule, remnants of of the mitotic spindle - Rarely seen
47 PERIPHERAL BLOOD FINDINGS Hemoglobin – decreasedHematocrit – decreasedRBC count – decreased/normalMCV - >100fl ( normal 82-98fl)MCH –increasedMCHC – NORMALReticulocytopenia.Total WBC count – normal / lowPlatelet count – normal/ lowPancytopenia, especially if anaemia is sever.
48 PERIPHERAL SMEAR RBC: Poikilocytosis - tear drops and schistocytes Anisocytosis - oval macrocytes-Macro ovalocytes (macrocytic normochromic)-well hemogloibised, thicker than normal-inclusions like HOWELL JOLLY BODIES, basophilic stippling, Cabot rings
49 PERIPHERAL SMEAR WBC: Normal count or reduced count Hypersegmented neutrophils (>5 lobes)MACRO POLYMORPHO NUCLEAR CELLS (Macropolys)PLATELETS:Normal or decreased
55 BONE MARROW Markedly hypercellular Myeloid : erythroid ratio decreased or reversed. (Normally, there are three myeloid precursors for each erythroid precursor resulting in a 3:1 ratio, known as the M:E (myeloid to erythroid) ratio)Erythropoiesis : MEGALOBLASTIC
56 MEGALOBLAST Abnormally large precursor Deeply basophilic royal blue cytoplasmFine chromatin with prominent nucleoliNuclear cytoplasmic asynchronyAbnormal mitosesMaturation arrest
57 Megaloblastic anemias Morphology Bone marrowNuclear cytoplasmic asynchrony in both erythroid and myeloid lineagesMegaloblasticNormalMegaloblasticMegaloblastic
62 BIOCHEMICAL FINDINGSIncrease in serum unconjugated bilirubin- because of ineffective erythropoiesisIncrease is LDHNormal serum iron and ferritin
63 TESTS FOR FOLATE AND B12 DEFICIENCY Serum folate assayRed cell folate assaySerum B12 assay
64 Pernicious AnemiaDecreased secretion of intrinsic factor due to gastric atrophy and loss of parietal cellsMore common in individuals of Northern European descent greater than age 50Most common cause of vitamin B12 deficiencyDiagnosisIntrinsic factor antibodies (commonly blocks B12 binding site)Sensitivity 50-84%Specificity ~100%Parietal cell antibodiesLess specific~50% sensitive
65 PATHOGENESISImmunologically mediated, autoimmune destruction of gastric mucosaCHRONIC ATROPHIC GASTRITIS – marked loss of parietal cellsThree types of antibodies:Type I antibody- 75% - blocks vitamin B12 and IF bindingType II antibody – prevents binding of IF-B12 complex with ileal receptorsType III antibody – 85-90% patients – against specific structures in the parietal cellAssociated with other autoimmune diseases like autoimmune thyroiditis
66 DIAGNOSTIC FEATURES Moderate to severe megaloblastic anemia Leucopenia with hypersegmented neutrophilsMild to moderate thrombocytopeniaMild jaundice due to ineffective erythropoiesis and peripheral hemolysisNeurologic changesLow levels of serum B12Elevated levels of homocysteineStriking reticulocytosis after parenteral administration of vitamin B12Serum antibodies to intrinsic factor
67 Therapy B12 Oral or intramuscular therapy Both work well but IM is preferred for patients with an absorption problemFolic acid1-5mg orally for one to four months (or till macrocytic anemia resolves)Folic acid will correct the hematologic but not the neurologic sequelae of B12 deficiency!!!!!MUST rule out B12 deficiencyResponseReticulocytes rise after Day 4 and peak on day 5-8Hemoglobin rises 2-3g/dL every 2 weeksMarrow begins to respond within daysHypersegmented neutrophils may persist for up to 2 weeks
69 Alcohol Common cause of macrocytosis Regular ingestion of 80g alcohol per day (1 bottle of wine)Abstinence form alcohol leads to resolution of macrocytosis in 2-4 months~90% of alcoholics have a macroytosis ( fL) before anemia developsMultifactorial in etiologyDirect toxic effectAssociated liver diseaseReticulocytosis related to GI bleedingCo-incident folate deficiency
70 Liver disease Hyperlipidemia Hypothyroidism Artifact Macrocytosis and target cellsMechanism not well understoodMay be related to increased lipid deposition on RBC membranesHyperlipidemiaHypothyroidismMechanism unknown~10% of patients with autoimmune thyroiditis have pernicious anemiaArtifactHyperglycemia (>600)RBC agglutination
71 Summary Macrocytic anemias can be megaloblastic or non megaloblastic Megaloblastic anemia has characteristic morphologic featuresNuclear cytoplasmic asynchronyB12 and folate deficiency are 2 reversible causes of megaloblastic anemia
72 CaseA 66 yo homeless man presents with generalized confusion, bruises and lacerations secondary to a witnessed fall down a flight of stepsPhysical exam revealed a laparotomy scarA CBC shows the following7.82.10824MCV 129A peripheral blood smearis reviewedWhat additional laboratorytests would you like torequest?
73 Diagnosis ?? ETOH Elevated B12 63 pg/mL (211 – 911) Folate ng/mL (>5.4)RBC Folate 805 ng/mL (293 – 809)Diagnosis ??Megaloblastic anemiaB12 deficiencyAs the patient’s mental status cleared he reported that the scar on his abdomen was secondary to a partial bowel resection including a large segment of ileum
74 Case RPI=3.4 Reticulocyte 9% What is the RPI? [9% X (30/45)]/1.75 12 year old boy with no significant past medical history presents to his pediatrician with persistent poor appetite and weakness 1 week following an acute viral illnessHe is found to be anemicReticulocyte 9%What is the RPI?10[retic% X (Pt Hct/45)]/MATMAT = (45 - Pt's HCT) ) (1.75 in our case)518030[9% X (30/45)]/1.75MCV 91MCHC 35.9RPI=3.4
75 Additional labs and peripheral blood smear HaptoglobinIndirect bilirubinNo increase in:Plasma hemoglobinUrine hemoglobinExtravascular hemolysisSplenomegalyon examOf note, the mother had a similar peripheral blood smear