Anemias (Except Hemoglobinopathies) PDF

Anemias (Except Hemoglobino- pathies) Michael M. Yakubovskyy, MD, PhD Content Part 1. Hemolytic Anemias (Except Sickle Cell and HbC Diseases, and Thalassemias) Part 2. Anemias due to Diminished Erythropoiesis (Except Megaloblastic Anemias) Part 3. Macrocytic (Megaloblastic) Anemias...

Anemias (Except Hemoglobino- pathies) Michael M. Yakubovskyy, MD, PhD Content Part 1. Hemolytic Anemias (Except Sickle Cell and HbC Diseases, and Thalassemias) Part 2. Anemias due to Diminished Erythropoiesis (Except Megaloblastic Anemias) Part 3. Macrocytic (Megaloblastic) Anemias Part 4. Anemias due to Blood Loss Part 1. Hemolytic Anemias (Except Sickle Cell and HbC Diseases, and Thalassemias)  The Place of Hemolytic Anemias in Working Classification Anemia: ↓Hb Normocytic anemia: MCV = 80-100 µm3 Microcytic anemia: MCV < 80 µm3 Macrocytic anemia: MCV > 100 µm3 Anemias due to ↑RBC destruction Anemias due to ↓RBC production (hemolytic anemias) Anemias with extravascular Anemias with intravascular hemolysis hemolysis Paroxysmal nocturnal Folate-deficiency Sickle cell anemia Aplastic anemia Thalassemia hemoglobinuria megaloblastic anemia Hb C anemia Pure red cell aplasia Iron-deficiency anemia Anemia resulting from Vitamin B12-deficiency trauma to RBCs megaloblastic anemia Hereditary spherocytosis Myelophthisic anemia Sideroblastic anemia G6PD deficiency Alcohol abuse macrocytic Anemia of chronic kidney Anemia of inflammation anemia G6PD deficiency disease Macrocytic anemia in liver Immune hemolytic anemia Anemia of inflammation disease Anemia in malaria Learning Objectives Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO1. Hereditary spherocytosis (HS) - LO2. G6PD-deficiency anemia - LO3. Immune hemolytic anemias (IHA): warm antibody and cold agglutinin types - LO4. Anemia in malaria - LO5. Paroxysmal nocturnal hemoglobinuria (PNH) - LO6. Hemolytic anemia resulting from trauma to RBCs Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO1. Hereditary spherocytosis (HS) Hereditary Spherocytosis (HS) Common in Northern Europe Autosomal dominant disorder due to a defect in the RBC membrane skeleton Outcome: loss of membrane fragments —> decrease in RBC surface membrane —> spherocytes RBC abd spherocytes —- Mustafa I, Al Marwani A, Mamdouh Nasr K, Abdulla Kano N, Hadwan T. Time RB concave w malaria ——- Moxon CA, Grau GE, Dependent Assessment of Morphological Changes: Craig AG. Malaria: modification of the red blood cell Leukodepleted Packed Red Blood Cells Stored in and consequences in the human host. Br J SAGM. Biomed Res Int. 2016;2016:4529434. doi: Haematol. 2011 Sep;154(6):670-9. doi: 10.1111/ 10.1155/2016/4529434. Epub 2016 Jan 21. PMID: j.1365-2141.2011.08755.x. Epub 2011 May 28. 26904677; PMCID: PMC4745630. PMID: 21623767; PMCID: PMC3557659. 3 normal RBCs in the center Spherocyte  Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO1. Hereditary spherocytosis (HS) HS: Ankyrin, Band 3, and ß-Spectrin Location, Diagram Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO1. Hereditary spherocytosis (HS) HS: Mechanism of RBC Changes, Diagram Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO1. Hereditary spherocytosis (HS) HS: Clinical Manifestations Anemia Splenomegaly: 0.5 - 1.0 kg Intermittent jaundice usually due to a viral infection with following hemolytic crisis Parvovirus B19 infection —> aplastic crisis Gallstones Leg ulcers NB: spectrum of clinical manifestations: mild-to-moderate-to-severe - Majority of HS patients presents a mild clinical course - Some patient may develop a life-threatening anemia and require blood transfusions  Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO1. Hereditary spherocytosis (HS) HS: Lab Findings (CBC) RBC count: normal-to-reduced Normocytic RBCs (MCV 80-100 µm3) Hb: normal-to-reduced HCT: normal-to-reduced MCH: normal-to-reduced MCHC: increased Reticulocyte count: increased (>3%) Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO1. Hereditary spherocytosis (HS) HS: Additional Lab Findings PBS - Spherocytosis: small RBCs without central pallor (MCV, MCH, and HCHC are normal) Characteristic, but not pathognomonic: also seen in immune hemolytic anemias (IHA) - Polychromasia/reticulocytosis - In severe cases: nucleated RBCs and Howell-Jolly bodies Bone marrow: erythroid hyperplasia with a normoblastic reaction Serum bilirubins: unconjugated hyperbilirubinemia Diagnosis of HS in asymptomatic patients requires a confirmation with osmotic fragility test Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO1. Hereditary spherocytosis (HS) HS: Small RBCs without Central Pallor, PBS https://commons.wikimedia.org/wiki/File:Spherocytes_(4670166434).jpg Ed Uthman from Houston, TX, USA, CC BY 2.0 , via Wikimedia Commons  Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO1. Hereditary spherocytosis (HS) HS: Osmotic Fragility Test Spherocytes start to lyse (red line) in 0.85% NaCl Normal biconcave RBC lyse in 0.5-0.3% NaCl solution solution Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO1. Hereditary spherocytosis (HS) HS: Treatment and Treatment Side-Effects Splenectomy —> elimination of splenic sequestration —> reduction in phagocytosis of spherocytes and their extravascular hemolysis —> reduction of anemia and other manifestations - Confirmation of splenectomy in PBS: increased amount of Howell-Jolly bodies (illustrated), appearance of target cells Side-effects of splenectomy - Reduction in immunity to encapsulated microorganisms (pneumococci, meningococci, Howell-Jolly bodies H. influenzae type B) —> sepsis - Hepatic and mesenteric thrombosis Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO2. G6PD-deficiency anemia G6PD Deficiency A recessive X-linked disorder Common in Africa, Mediterranean, and among African Americans Probably protects from Plasmodium falciparum malaria As a rule, not so severe as SCA, thalassemias, and HS Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias: LO2. G6PD-deficiency anemia Sequelae of G6PD Deficiency 1. G6PD-deficiency 2. Limited production of NADPH 3. Limited production of reduced glutathione (GSH) 4. Limited ability to metabolize H2O2 5. Accumulation of pro-oxidant compounds (e.g., superoxide) 6. Cross-linking of reactive sulfhydryl groups in globin chains 7. Precipitation of denatured globins with formation of Heinz bodies Legend - Rasburicase administered to degrade uric acid produces an equimolar amount of H2O2 - H2O2 is rapidly degraded by the combined action of glutathione peroxidase, catalase and Prx2 (peroxiredoxin-2); all three mechanisms are NADPH dependent Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO2. G6PD-deficiency anemia G6PD-Deficiency Anemia: Extra- and Intravascular Hemolysis 1. Oxidative stress in G6PD-deficient individuals - Infections. e.g., pneumonia or viral hepatitis —> inflammatory response —> generation of ROS - Drugs, e.g., antimalarials, sulfonamides, nitrofurantoins - Food, e.g., fava beans 2. Cross-linking of sulhydryl groups in globin chains 3. Formation of globin precipitates attached to the cytomembrane (Heinz bodies) 4. Episodic hemolysis - Extravascular: fragments of RBC membrane with attached Heinz bodies are plucked out by splenic macrophages —> formation of bite cells and spherocytes - Intravascular: Heinz bodies directly damage the RBC membrane Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO2. G6PD-deficiency anemia G6PD Deficiency Anemia: Clinicolaboratory Correlates Episodes of acute hemolysis 2-3 days after oxidant exposure: anemia, hemoglobinemia, and hemoglobinuria No features of chronic hemolysis: neither splenomegaly, nor cholelithiasis Lab findings - Bite cells - Spherocytes - Heinz bodies identified with supravital stains A: control; B and C: bite cells  Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO2. G6PD-deficiency anemia G6PD Deficiency Anemia: PBS Bite Cells Heinz bodies (cresyl violet) Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO3. Immune hemolytic anemias (IHA): warm antibody and cold agglutinin types Immune Hemolytic Anemia (IHA) Also known as autoimmune hemolytic anemia (AIHA) Types - Warm antibody type (80%) IgGs bind RBCs at 37˚ C (Warm is Good) - Cold agglutinin type (20%) IgMs bind RBCs at lower temperature (best 0-4˚ C) Extravascular hemolysis in both types Both direct and indirect Coombs tests are positive in both types Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO3. Immune hemolytic anemias (IHA): warm antibody and cold agglutinin types Warm Antibody IHA: Etiology and Pathogenesis 1. Predisposing conditions can be identified in ≈50% of cases: - Autoimmune diseases, primarily SLE - Drugs Antigenic drugs: penicillins and cephalosporins Tolerance-breaking drugs: α-methylodopa - Lymphoid neoplasms 2. Production of antibodies (IgGs) 3. Attachment of IgGs to RBC surface 4. Binding of IgGs to Fc-receptors on splenic macrophages 5. Plucking out of RBC fragments (extracellular hemolysis, as in HS) —> spherocytosis  Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO3. Immune hemolytic anemias (IHA): warm antibody and cold agglutinin types Cold Agglutinin IHA: Etiology and Pathogenesis 1. Predisposing factors - Infections: Mycoplasma pneumoniae, EBV, CMV, HIV, etc. - Lymphoid neoplasms 2. Transient production of antibodies (IgMs) 3. Attachment of IgMs to RBC surface in the body parts with temperature below 30°C (fingers, toes, and ears) 4. Agglutination of RBCs (—> Raynaud phenomenon) 5. Activation of complement (particularly C3b) 6. Recognition of C3b by macrophages in the spleen, liver, and BM 7. Plucking out of RBC fragments (extracellular hemolysis, as in HS) —> spherocytosis Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias LO3. Immune hemolytic anemias (IHA): warm antibody and cold agglutinin types IHA (Both Warm and Cold): Lab Findings, CBC Normocytic normochromic anemia - Hb: reduced - RBC count: reduced - HCT: reduced - MCV: 80-100 µm3 - MCH: ≈ normal - MCHC: ≈ normal - Reticulocyte count (corrected, CRC): increased: >3% Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO3. Immune hemolytic anemias (IHA): warm antibody and cold agglutinin types IHA (Both Warm and Cold): Additional Lab Findings PBS - Spherocytosis: small RBCs without central pallor (MCV, MCH, and HCHC are normal) Characteristic, but not pathognomonic: also seen in HS - Polychromasia/reticulocytosis - In severe cases: nucleated RBCs and Howell-Jolly bodies - In cold antibody IHA: spontaneous RBC agglutination in PBS In severe cases: erythroid hyperplasia of the BM and normoblastic reaction Serum bilirubins: unconjugated hyperbilirubinemia  Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO3. Immune hemolytic anemias (IHA): warm antibody and cold agglutinin types Warm Antibody IHA: PBS A. Blood film showing moderately severe autoimmune hemolytic anemia (AHA). Note the high frequency of microspherocytes (small hyperchromatic RBCs) and the high frequency of macrocytes (putative reticulocytes). B. Blood film showing severe AHA. Note the low density of red cells on the film (profound anemia), high frequency of microspherocytes (hyperchromatic), and the large red cells (putative reticulocytes). Note the two nucleated RBCs and the Howell-Jolly body (nuclear remnant) in the macrocyte. Nucleated RBCs and Howell-Jolly bodies may be seen in AHA with severe hemolysis or after splenectomy. C. Blood film showing severe AHA. Monocyte engulfing two red cells (erythrophagocytosis). Note the frequent microspherocytes and scant red cell density. D. Reticulocyte preparation showing AHA. Note the high frequency of reticulocytes, the large cells with precipitated ribosomes. The remaining cells are microspherocytes. (Reproduced with permission from Lichtman’s Atlas of Hematology, www.accessmedicine.com.) Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO3. Immune hemolytic anemias (IHA): warm antibody and cold agglutinin types Cold Antibody IHA: PBS Two PBSs (images) from the same patient - Image A: spontaneous RBC agglutination at 30°C (cold) - Image B: no RBC agglutination at 37°C (warm) Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO4. Anemia in malaria Anemia in Malaria Anemia-inducing plasmodia - P. falciparum Quotidian fever: daily spikes with no pattern Affects both young and old RBCs —> severe anemia - P. vivax Tertian fever pattern: every 48 hours Affects only young RBCs —> less severe anemia Mechanisms of P. falciparum-induced anemia - Extravascular hemolysis: infected RBCs are recognized by splenic macrophages and removed from the circulation—> splenomegaly - Diminished erythropoiesis: plasmodia —> release of IFN-γ and TNF-α — > inhibition of erythropoietin response (anemia of inflammation)  Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO4. Anemia in malaria Anemia in Malaria: Misshapen RBCs and Intracellular Plasmodia UR and LL: two infected with P. falciparum RBCs Ring forms of P. falciparum in the RBCs RB concave w malaria ——- Moxon CA, Grau GE, Craig AG. Malaria: modification of the red blood cell and consequences in the human host. Br J Haematol. 2011 https://commons.wikimedia.org/wiki/File:Plasmodium_falciparum,_peripheral_blood_(37093691502).jpg Sep;154(6):670-9. doi: 10.1111/j.1365-2141.2011.08755.x. Epub 2011 May 28. PMID: 21623767; PMCID: PMC3557659. Ed Uthman from Houston, TX, USA, CC BY 2.0 , via Wikimedia Commons Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO5. Paroxysmal Nocturnal Hematuria (PNH) Paroxysmal Nocturnal Hemoglobinuria (PNH) A rare acquired genetic disorder that affects PIGA gene on X-chromosome (with possible lionization) manifested as intravascular hemolysis (persistent > paroxysmal) - Neither inherited, nor congenital PIGA: phosphatidylinositol glycan class A PIGA function: to catalyze the transfer of a glycosylphosphatidyl inositol (GPI) to proteins that regulate (inhibit) complement activity PGI-linked proteins - CD55: decay accelerating factor (DAF) - CD59: membrane inhibitor of reactive lysis (MIRL) Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO5. Paroxysmal Nocturnal Hematuria (PNH) PNH: Hematologic Lab Findings CBC - RBC count: normal-to-reduced (mild-to-moderate-to-severe anemia) - MCV: normal-to-increased (normocytic-to-macrocytic RBCs) With hemoglobin- and hemosiderinuria, and following iron- deficiency, RBCs may turn to microcytic - Reticulocyte count (corrected) markedly increased (3% —> 20%) PBS: not remarkable Bone marrow: erythroid hyperplasia Flow cytometry: see the next slide  Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO5. Paroxysmal Nocturnal Hematuria (PNH) PNH: Flow Cytometry The gold standard test for PNH Carried out on RBCs and granulocytes Diagnostic feature: a bimodal distribution of cells with a discrete population that is CD59 and CD55 negative Legend: Staining patterns of red cells from a normal individual (A) and a patient (B) with paroxysmal nocturnal hemoglobinuria (PNH). About half of the red cells in the PNH patient are deficient in CD59 Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO5. Paroxysmal Nocturnal Hematuria (PNH) PNH: Serum and Urine Lab Findings Serum - Tests for intravascular hemolysis Hemoglobinemia Unconjugated hyperbilirubinemia Low-to-absent haptoglobin Markedly elevated LDH - Special tests for PNH Acidified serum (Ham) test - A highly reliable test, but available only in few laboratories - Sucrose lysis test: not so good as acidified serum test Urine Acidified (Ham) test - Left tube: hemolysis —> PNH - Hemoglobinuria - Right tube: control - Hemosiderinuria Nakamura, N., Sugawara, T., Shirato, Ki. et al. Paroxysmal nocturnal hemoglobinuria in systemic lupus erythematosus: a case report. J Med Case Reports 5, 550 (2011). https://doi.org/10.1186/1752-1947-5-550 Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO5. Paroxysmal Nocturnal Hematuria (PNH) PNH: Clinical Findings Anemia: pallor, dyspnea, palpitations, etc. Chronic hemolysis: jaundice, dark urine (hemoglobin- and hemosiderinuria) Episodic (paroxysmal) hemolysis when complement is activated by mild acidosis, e.g., respiratory acidosis during sleep (nocturnal acidosis) Complications - Hemosiderinuria —> loss of iron —> iron-deficiency anemia - Venous thrombosis Hepatic veins: Budd-Chiari syndrome Portal and mesenteric veins: intestinal infarct Cerebral veins and sinuses - Bone marrow complications: aplastic anemia, acute myeloid leukemia, and myelodysplastic syndrome  Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO6. Hemolytic anemia resulting from trauma to RBCs Hemolytic Anemia Resulting from Trauma to RBCs Mechanical trauma to RBCs —> intravascular hemolysis and formation of fragmented RBCs (schistocytes; syn.: helmet cells) Classification, causes, and mechanisms - Macroangiopathic hemolysis: calcific aortic stenosis and prosthetic cardiac valves —> turbulent blood flow and pressure gradient across the damaged valves - Microangiopathic hemolytic anemia (MAHA): deposition of thrombi on the endothelial surface —> direct injury to RBCs, seen in Thrombotic thrombocytopenia purpura (TTP) Hemolytic-uremic syndrome (HUS) Disseminated intravascular coagulation (DIC) Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of the following hemolytic anemias - LO6. Hemolytic anemia resulting from trauma to RBCs Hemolytic Anemia Resulting from Trauma to RBCs: Lab Findings Features of hemolytic anemia with intravascular hemolysis, similar to PNH Characteristic feature in PBS: schistocytes (syn.: helmet cells, triangular cells) Part 2. Anemias due to Diminished Erythropoiesis (Except Megaloblastic)  Place of Anemias of Diminished Erythropoiesis in Working Classification Anemia: ↓Hb Normocytic anemia: MCV = 80-100 µm3 Microcytic anemia: MCV < 80 µm3 Macrocytic anemia: MCV > 100 µm3 Anemias due to ↑RBC destruction Anemias due to ↓RBC production (hemolytic anemias) Anemias with extravascular Anemias with intravascular hemolysis hemolysis Paroxysmal nocturnal Folate-deficiency Sickle cell anemia Aplastic anemia Thalassemia megaloblastic anemia hemoglobinuria Hb C anemia G6PD deficiency Pure red cell aplasia Iron-deficiency anemia Vitamin B12-deficiency megaloblastic anemia Anemia resulting from Hereditary spherocytosis Myelophthisic anemia Anemia of inflammation trauma to RBCs Alcohol abuse macrocytic anemia G6PD deficiency Anemia of chronic kidney Sideroblastic anemia disease Macrocytic anemia in liver Immune hemolytic anemia disease Anemia of inflammation Anemia in malaria Learning Objectives Classification Category of Type of Anemia LOs Anemias Aplastic anemia and LO1. Compare and contrast the aplastic anemia and pure red cell aplasia in terms of pure red cell aplasia etiology, mechanisms, and clinical, laboratory, and morphologic presentation Normocytic anemias due to LO2. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them Myelophthisic anemia diminished with associated clinical features of myelophthisic anemia erythropoiesis Anemia of chronic LO3. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them kidney disease with associated clinical features of anemia of chronic kidney disease LO4. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them Iron-deficiency anemia with associated clinical features of iron-deficiency anemia Anemia due to LO5. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them Microcytic inflammation with associated clinical features of anemia due to inflammation anemias due to diminished LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them erythropoiesis Sideroblastic anemia with associated clinical features of sideroblastic anemia; outline major clinicopathologic features of lead poisoning LO7. Interpret the indices used in the “iron panel” and provide differential diagnosis of microcytic hypochromic 38 anemias based on iron panel data LO1. Compare and contrast the aplastic anemia and pure red cell aplasia in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Aplastic Anemia (AA): Definition Aplastic anemia: a life-threatening bone marrow (BM) failure manifested by - BM hypoplasia due to suppression of multipotent myeloid cells - Pancytopenia (anemia, neutropenia, and thrombocytopenia) in the peripheral blood (PB) LO1. Compare and contrast the aplastic anemia and pure red cell aplasia in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Aplastic Anemia (AA): Clinicopathologic Correlates Anemia: pallor and/or signs of congestive heart failure, such as shortness of breath, or pedal edema Neutropenia: fever, cellulitis, pneumonia, hepatitis (with jaundice), or sepsis Thrombocytopenia: bruising (e.g., ecchymoses, petechiae), gum bleeding, or nosebleeds LO1. Compare and contrast the aplastic anemia and pure red cell aplasia in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation AA: Etiology Congenital/inherited: ≈20% - Examples: Fanconi anemia and telomerase diseases (dyskeratosis congenita) Acquired: ≈80%; in majority of cases, the etiology is unknown Known causes of acquired AA - Chemicals and drugs: see the next slide - Whole body (ionizing) radiation - Viruses: EBV, HIV, unknown hepatitis virus, etc. - Autoimmune diseases: SLE, RA - PNH LO1. Compare and contrast the aplastic anemia and pure red cell aplasia in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation AA: : Chemicals and Drugs (in Alphabetic Order) Antibiotics Anti-convulsants Benzene Chemotherapeutic drugs Chloramphenicol Gold NSAIDs Penicillamine Sulfonamides LO1. Compare and contrast the aplastic anemia and pure red cell aplasia in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation AA: Pathogenesis Postulated mechanisms - Extrinsic: immune-mediated suppression of hematopoiesis 1. Alteration in antigen presentation on the surface of stem cells 2. Activation of cellular immune response 3. Activation of TH1 4. Release of IFNγ and TNF 5. Suppression and death of stem cells - Intrinsic: absent or defective stem cells (stem cell failure), e.g., telomerase defects LO1. Compare and contrast the aplastic anemia and pure red cell aplasia in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation AA: Investigations CBC Reticulocyte count Blood film VitB12/folate Liver function tests Virology BM aspiration and trephine/core biopsy PNH screening LO1. Compare and contrast the aplastic anemia and pure red cell aplasia in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation AA: PB Findings Anemia with morphologically normal RBCs (normocytic normochromic anemia) - The reticulocyte count (RC) < 1% WBC changes - Neutropenia/agranulocytosis: a decrease in all PMNs - Low monocyte count - Relative lymphocytosis Thrombocytopenia The severity of aplastic anemia is assessed via the degree of cytopenia  LO1. Compare and contrast the aplastic anemia and pure red cell aplasia in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation AA, Neutro- and Thrombocytopenia, PBS Control https://commons.wikimedia.org/wiki/File:Normal_Adult_Blood_Smear.JPG https://commons.wikimedia.org/wiki/File:Blood-rbcs.jpg Keith Chambers, CC BY-SA 3.0 , via Wikimedia Commons Echinaceapallida, CC BY-SA 4.0 , via Wikimedia Commons LO1. Compare and contrast the aplastic anemia and pure red cell aplasia in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation AA, Hypocellular BM, Trephine BM aspiration: hypocellularity/hypoplasia/aplasia BM (“dry tap”) BM trephine (better than aspiration): hypocellularity (BM cellularity decreased RBCs production - Granulocytic and platelet precursors are normal Major causes - Thymoma —> ?production of autoantibodies to erythropoietin (EPO) - Parvovirus B19 infection Previously healthy individuals —> transient reduction in RBC precursors —> recovery Patients with existing hemolytic anemia —> cessation of erythropoiesis (aplastic crisis) LO1. Compare and contrast the aplastic anemia and pure red cell aplasia in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Pure RBC Aplasia, BM, Trephine https://openi.nlm.nih.gov/detailedresult? img=PMC2737792_1752-1947-0003-0000007335-2&query=bone marrow biopsy&it=xg,mc,ph&lic=by&req=4&npos=48 LO2. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of myelophthisic anemia Myelophthisic Anemia BM failure due to space-occupying lesions that destroy BM components - Any disease associated with BM infiltration = "myelophthisic" processes Major causes - Metastatic cancer, mostly breast, lung, and prostate - Granulomatous inflammation, e.g., TB or sarcoidosis - Myelofibrosis (a form of myeloproliferative disorders studied with WBC Disorders) PBS: leukoerythroblastosis: nucleated RBCs and immature myeloid cells (metamyelocytes, myelocytes) LO2. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of myelophthisic anemia Myelophthisic Anemia, PB and BM PBS - Pancytopenia - Tear-drop RBCs - Leukoerythroblastosis: immature erythroid and myeloid cells in the peripheral blood BM trephine - Evidence of a primary process: cancer, granulomatous inflammation, fibrosis, etc. - Hypocellularity https://commons.wikimedia.org/wiki/File:Myelofibrosis,_Reticulin_Stain_(6032644716).jpg Ed Uthman from Houston, TX, USA, CC BY 2.0 , via Wikimedia Commons LO3. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of anemia due to chronic kidney disease Anemia of Chronic Kidney Disease Major mechanism: reduced EPO production - In normal individuals, EPO is produced by renal cortex interstitial cells under the influence of low pO2 (hypoxia) Labs: mild-to-moderate-to-severe anemia CBC and PBS parameters - Normocytic normochromic RBCs In advanced stages, iron deficiency may develop, and the anemia may turn to microcytic hypochromic - Reticulocyte count high transferrin) synthesis is regulated by ferritin] Transferrin saturation (TSAT) Low 20 - 50% (serum iron/transferrin) (low iron and high transferrin) Iron in BM, Prussian blue stain Adequate presence of iron: macrophages No iron (the gold standard) with iron, few sideroblasts (not ringed) *Erythrocyte zinc protoporphyrin 30 - 70 ng/mL RBC High *Erythrocyte zinc protoporphyrin (EZP): a complex of Zn and protoporphyrin IX. It is produced when iron cannot be incorporated in the protoporphyrin ring, e.g., in iron-deficiency or lead poisoning. In thalassemias, heme synthesis is not affected, and EZP is normal LO5. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of anemia of inflammation Anemia of Inflammation Syn.: anemia of chronic inflammation, anemia of chronic disease Causes - Chronic bacterial infections, e.g., osteomyelitis, or lung abscess - Chronic immune disorders, e.g., SLE, or IBD (inflammatory bowel disease) - Malignant tumors, e.g., carcinoma of the lung or breast Neoplastic cells induce a chronic inflammatory response with following cytokine release Two mechanisms: inflammation —> - IL-6 synthesis —> activation of hepsidin —> inhibition of ferroportin —> sequestration of iron in enterocytes, BM macrophages, and hepatocytes —> iron deficiency —> reduced iron supply to erythroid progenitors —> inhibition of erythropoiesis - Reduction in EPO synthesis —> inhibition of erythropoiesis LO5. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of anemia of inflammation Anemia of Inflammation: Clinicolaboratory Correlates Mild-to-moderate anemia: normocytic normochromic —> microcytic hypochromic - Hepsidin-mediated iron-deficiency contributes to transformation of normocytic normochromic anemia to microcytic hypochromic CBC - Normal-to-low MCV, MCH, and MCHC - RDW: normal - Reticulocyte count: no activation of transferrin) Low Transferrin saturation (iron is more deficient that transferrin) Accumulation of iron in macrophages Iron in BM No sideroblasts Erythrocyte zinc protoporphyrin High LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of sideroblastic anemia; outline major clinicopathologic features of lead poisoning Sideroblastic Anemia Microcytic hypochromic anemia with following characteristic features - Mitochondrial defect, iron supply/store is adequate - Iron accumulates in mitochondria arranged in a ring/circle around the nuclei of proerythroblasts (“ringed sideroblasts”) - Incorporation of iron into Hb is inhibited Causes - Genetic causes —> hereditary anemias, e.g., X-linked sideroblastic anemia due to deficiency in ALAS2 [δ-aminolevulinic acid (δ-ALA) synthase 2] - Acquired causes Lead (Pb) poisoning —> denaturation of ferrochelatase Alcoholism —> mitochondrial damage Pyridoxine (B6) deficiency —> inhibition of δ-ALA synthase 2 (mostly associated with isoniazid therapy of TB) Myelodysplastic syndrome (MDS) with ringed sideroblasts LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of sideroblastic anemia; outline major clinicopathologic features of lead poisoning Heme Synthesis, Diagram LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of sideroblastic anemia; outline major clinicopathologic features of lead poisoning Sources of Lead Environmental - Lead-containing house paints - Flaking lead paint in older houses - Pica (abnormal craving) for eating lead-based paint Occupational/recreational - Mining, foundries - Pottery painting with lead-based paints - Automobile industry: lead-acid battery incineration - Painting LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of sideroblastic anemia; outline major clinicopathologic features of lead poisoning Major Features of Lead Poisoning Toxic concentration in the blood: 10 - 150 μg/dL Major organs/systems involved - Bone marrow —> sideroblastic anemia - GIT —> abdominal “lead” colic Gingiva —> bluish gingival “lead lines” - Kidneys —> nephropathy - Nervous system Children —> CNS involvement —> encephalopathy Adults —> PNS involvement —> peripheral demyelinating neuropathy (“wrist drop” and “foot drop” signs) - Bones in children —> epiphyseal “lead lines” on x-ray (lead competes with Ca2++ ions and gets deposited in the epiphyses of growing bones) LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of sideroblastic anemia; outline major clinicopathologic features of lead poisoning Lead Poisoning, Gingival Lead Lines (a) and Wrist Drop (b) https://openi.nlm.nih.gov/detailedresult?img=PMC2812735_AIAN-12-111-g001&query=&req=4 LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of sideroblastic anemia; outline major clinicopathologic features of lead poisoning Lead Poisoning, Accumulation of Lead in the Kidney and Femoral and Tibial Epiphyses (Lead Lines), X-ray LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of sideroblastic anemia; outline major clinicopathologic features of lead poisoning Mechanisms of Lead-Induced Sideroblastic Anemia Pb binds to disulphide groups and damage enzymes involved in heme synthesis - Denaturation of ferrochelatase —> inability to incorporate iron in protoporphyrin ring - Denaturation of ALA dehydrase —> inability to convert ALA to porphobilinogen - Denaturation of ribonuclease —> prevention of breakdown of ribosomes —> persistence and aggregation of ribosomes —> coarse basophilic stippling in mature RBCs LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of sideroblastic anemia Sideroblastic Anemia: Labs All sideroblastic anemias - CBC: Low MCV, MCH, and MCHC - PBS Microcytic hypochromic RBCs with Coarse basophilic stippling - BM Ringed sideroblasts (≥ 5 granules in a peri-nuclear position, encircling one-third or more of the circumference of the nucleus) Iron-laden macrophages (ferritin and hemosiderin) Additional tests for Pb-induced sideroblastic anemia - Elevated Pb level in blood and urine - Elevated δ-ALA level in the urine LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of sideroblastic anemia Sideroblastic Anemia, PBS, Coarse Basophilic Stippling LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of sideroblastic anemia Sideroblastic Anemia, Labs Parameter Sideroblastic anemia RBC inclusions Coarse basophilic stippling High Serum iron (deficient incorporation of iron in protoporphyrin; iron absorption and transportation are not affected) High Serum ferritin (iron transportation and storage are not affected) Low Transferrin (high ferritin —> low transferrin) High Transferrin saturation (high iron and low transferrin) Accumulation of iron in macrophages and Iron in BM proerythroblasts (ringed sideroblasts) Erythrocyte zinc protoporphyrin High LO6. Explain the etiology, pathogenesis and laboratory diagnosis, and correlate them with associated clinical features of sideroblastic anemia Sideroblastic Anemia, BM Aspirate Sideroblasts Two BM macrophages stained for iron LO7. Interpret the indices used in the “iron panel” and provide differential diagnosis of microcytic hypochromic anemias based on iron panel data Thalassemias (Microcytic Hypochromic Anemias), Labs Parameter Thalassemias ß-thal: basophilic stippling, nucleated RBCs RBC additional features ⍺-thal: aggregates of HbH similar to Heinz bodies, or aggregates of Hb Barts (supravital stain) Normal-to-high Serum iron (activated intestinal absorption, ineffective erythropoiesis) Normal-to-high Serum ferritin (higher iron —> higher ferritin) Normal-to-low Transferrin (Higher ferritin —> lower transferrin) Normal-to-high Transferrin saturation (normal-high iron and normal-to-low transferrin) Iron in BM Accumulation of iron in macrophages Erythrocyte zinc protoporphyrin Normal LO7. Interpret the indices used in the “iron panel” and provide differential diagnosis of microcytic hypochromic anemias based on iron panel data Laboratory DDx in Microcytic Hypochromic Anemias Iron-deficiency Anemia of Sideroblastic Parameter Thalassemias anemia Inflammation anemia Basophilic stippling RBC characteristic Coarse basophilic Nucleated RBCs features stippling Aggregates of HbH Aggregates of Hb Barts Serum iron ↓ ↓ ↑ Normal to ↑ Serum ferritin ↓ ↑ ↑ Normal to ↑ Transferrin ↑ ↓ ↓ Normal to ↓ Transferrin saturation ↓ ↓ ↑ Normal to↑ ↑↑ (macrophages Iron in BM store None ↑ (macrophages) ↑ (macrophages) and sideroblasts) Erythrocyte zinc ↑ ↑ ↑ Normal protoporphyrin  Part 3. Macrocytic (Megaloblastic) Anemias Place of Megaloblastic Anemias in Working Classification Anemia: ↓Hb Normocytic anemia: MCV = 80-100 µm3 Microcytic anemia: MCV < 80 µm3 Macrocytic anemia: MCV > 100 µm3 Anemias due to ↑RBC destruction Anemias due to ↓RBC production (hemolytic anemias) Anemias with extravascular Anemias with intravascular hemolysis hemolysis Paroxysmal nocturnal Folate-deficiency Sickle cell anemia Aplastic anemia Thalassemia megaloblastic anemia hemoglobinuria Hb C anemia G6PD deficiency Pure red cell aplasia Iron-deficiency anemia Vitamin B12-deficiency megaloblastic anemia Anemia resulting from Hereditary spherocytosis Myelophthisic anemia Anemia of inflammation trauma to RBCs Alcohol abuse macrocytic anemia G6PD deficiency Anemia of chronic kidney Sideroblastic anemia disease Macrocytic anemia in liver Immune hemolytic anemia disease Anemia of inflammation Anemia in malaria Learning Objectives LO1. Compare and contrast the B12- and folate-deficiency megaloblastic anemias in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation LO1. Compare and contrast the B12- and folate-deficiency megaloblastic anemias in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Macrocytic Anemia: Definition and Classification Macrocytes: RBCs with MCV > 100 fL Classification - Megaloblastic anemia (megaloblasts: large erythroblasts) - Vit B12 -deficiency anemia Folate (vit B9) deficiency anemia - Non-megaloblastic macrocytic anemias Alcohol-abuse macrocytic anemia Macrocytic anemia in chronic liver diseases LO1. Compare and contrast the B12- and folate-deficiency megaloblastic anemias in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Vit B12 and Folate Metabolism LO1. Compare and contrast the B12- and folate-deficiency megaloblastic anemias in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Intersection of Vit B12 and Folate Metabolism Legend: Cobalamin and folate intersect in the methionine synthase reaction where 5- methyl-THF is able to donate its methyl group to homocysteine to form methionine with cobalamin in the form of MeCbl serving a cofactor in the transfer of the methyl group. In this way, THF is regenerated. Cbl, cobalamin; MeCbl, methylcobalamin; THF, tetrahydrofolate LO1. Compare and contrast the B12- and folate-deficiency megaloblastic anemias in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Pathogenesis of Megaloblastic Anemia 1. Vit B12 - or folate deficiency 2. Deficient thymidine production 3. Inhibition of DNA synthesis 4. Delay in nuclear division and maturation with preserved maturation of cytoplasm in erythroid precursors 5. Nuclear-cytoplasmic asynchrony (cytoplasm > nucleus) with formation megaloblasts (large erythroblasts) 6. Ineffective erythropoiesis 7. Anemia; megaloblasts maturate to macro(ovalo)cytes LO1. Compare and contrast the B12- and folate-deficiency megaloblastic anemias in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Megaloblastic Anemia, BM Aspirate, Megaloblasts Central cluster: 9 h - early polychromatophilic normoblast; Left: promegaloblast; right: basophilic megaloblast 3h - late polychormatophilic normoblast with lobulated nucleus; 12 h - orthochromatic megaloblast (normoblast) LO1. Compare and contrast the B12- and folate-deficiency megaloblastic anemias in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Differential Diagnosis in Megaloblastic Anemias Vit B12 Folate Source Meat, eggs, and dairy products Fresh fruits and vegetables Stores last for 2-3 years Absorption site Ileum Duodenum and proximal jejunum Biochemical function Coenzymes in thymidine synthesis Vegetarian diet Causes for Excessive alcohol consumption Food overcooking deficiency Deficient absorption —> pernicious anemia Excessive alcohol consumption Chronic pancreatitis Pregnancy Ileal infection/resection Anemia Clinical features Atrophic glossitis Anemia of deficiency Subacute combined degeneration of the Neural tube defects in utero spinal cord Reversible cognitive deterioration  LO1. Compare and contrast the B12- and folate-deficiency megaloblastic anemias in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Differential Diagnosis in Megaloblastic Anemias 2 Vit B12 -Deficiency Folate Deficiency Variable pancytopenia due to apoptosis of hematopoietic cells in the BM ↑ MCV CBC and ↑MCH PBS ≈Normal MCHC Macroovalocytes (normochromic) Hypersegmented neutrophils (≥5 segments) BM Hypercellular BM with erythroid hyperplasia and megaloblasts aspirate Giant metamyelocytes and bands Giant megakaryocytes Increase serum homocysteine Increased urine methylmalonic acid Increased serum homocysteine Labs (bio- chemistry) [deficient function of methylmalonyl Normal urine methylmalonic acid coenzyme A (CoA) mutase] Reduced folate level in folate assay Reduced level of B12 in Vit B12 assay LO1. Compare and contrast the B12- and folate-deficiency megaloblastic anemias in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Megaloblastic Anemia, PBS, Macro(ovalo)cytes and Hypersegmented Neutrophils https://commons.wikimedia.org/wiki/File:Hypersegmented_Neutrophils_(36831145373).jpg Ed Uthman from Houston, TX, USA, CC BY 2.0 , via Wikimedia Commons LO1. Compare and contrast the B12- and folate-deficiency megaloblastic anemias in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Pernicious Anemia (PA) Adults, >40 years of age Underlying condition: chronic autoimmune atrophic gastritis with impaired production of intrinsic factor (IF) Pathogenesis of gastritis: autoimmune damage of parietal cells; mechanisms - CD4+T cells directed against H+/K+-ATPase - Autoantibodies to the IF or IF-VitB12 complex Clinical features = Vit B12-deficiency anemia Clinical findings unique to PA - Maldigestion due to chronic gastritis and achlorhydria - Increased incidence of gastric cancer LO1. Compare and contrast the B12- and folate-deficiency megaloblastic anemias in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation PA, Autoimmune Atrophic Gastritis, Histo https:// commons.wikimedia.org/ wiki/ File:Autoimmune_atrophic_g astritis_(H%26E),_very_high _mag.jpg CoRus13, CC BY-SA 4.0 , via Wikimedia Commons : Autoimmune atrophic gastritis showing atrophy of oxyntic mucosa, pyloric metaplasia and lymphoid aggregates. https://commons.wikimedia.org/wiki/File:Autoimmune_atrophic_gastritis_(H%26E),_high_mag.jpg CoRus13, CC BY-SA 4.0 , via Wikimedia Commons : Autoimmune atrophic gastritis showing atrophy of oxyntic mucosa, pyloric metaplasia and lymphoid aggregates. Loss of parietal cells, fibrosis, Control: isthmic portion of oxyntic glands with parietal cells mononuclear infiltrate Part 4. Anemias due to Blood Loss LO1. Compare and contrast the anemia due to acute blood loss and anemia due to chronic blood loss in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation 96 LO1. Compare and contrast the anemia due to acute blood loss and anemia due to chronic blood loss in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Anemia due to Blood Loss Classification - Anemia due to acute blood loss (posthemorrhagic anemia) - Anemia due to chronic blood loss Chronic bleeding (e.g., peptic ulcer or colon cancer) —> depletion of iron stores —> diminished erythropoiesis —> iron-deficiency anemia (covered above) 97 LO1. Compare and contrast the anemia due to acute blood loss and anemia due to chronic blood loss in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Anemia due to Acute Blood Loss Clinical effects depend upon - Rate of hemorrhage - Whether the bleeding is external or internal (e.g., with a non-lethal rupture of an abdominal aortic aneurysm, iron is recaptured) If patient survives: intra-vascular shift of water from the interstitial fluid compartment leads to - Hemodilution: low HCT - Reduced oxygen-carrying capacity —> ↓ pO2 —> activation of EPO synthesis —> erythroid hyperplasia —> reticulocytosis seen 5-7 days after bleeding Massive blood loss —> cardiovascular collapse —> hypovolemic shock —> death LO1. Compare and contrast the anemia due to acute blood loss and anemia due to chronic blood loss in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Anemia due to Acute Blood Loss: Labs CBC - Hb: low - HCT: low - WBC count: high due to mobilization of granulocytes from the intravascular marginal pool - Reticulocyte count (RC): —> 10-15% after 5-7 days - Platelet count: high due to activation of BM production PBS - First 3-4 days: normocytic normochromic RBCs (evacuated with the depot) - After 5-7 days: polychromasia (reticulocytosis) LO1. Compare and contrast the anemia due to acute blood loss and anemia due to chronic blood loss in terms of etiology, mechanisms, and clinical, laboratory, and morphologic presentation Posthemorrhagic Anemia, Polychromatophilic RBCs (PBS) and Erythroid Hyperplasia (BM Aspirate) The End