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Flashcards in RBC Disorders Deck (28):

What is the significance of the corrected reticulocyte count?

Indicates effective erythropoiesis (good marrow response to anemia) if ≥3%


Extramedullary hematopoiesis

• Erythropoiesis outside of bone marrow, often in liver or spleen
• Due to intrinsic bone marrow disease or accelerated erythropoiesis (ex. with severe hemolysis)
• Hepatosplenomegaly, "hair-on-end" sign on skull XR



• Decreased Hb, Hct, or RBC
• Normal SaO2 and PaO2
• Pulmonary valve murmur, pallor, high-output cardiac failure (from decreased viscosity)


What does increased RDW (RBC distribution width) indicate?

Iron-deficiency anemia


What do iron studies look like in anemia of chronic disease?

• Increased serum ferritin
• Decreased serum iron, TIBC (transferrin), iron saturation


What are the 4 chains in each HbA, HbF, HbH, and Hb Bart?

• HbA: 2 alpha, 2 beta
• HbF: 2 alpha, 2 gamma
• HbH: 4 beta
• Hb Bart: 4 gamma


Causes of iron deficiency anemia

Inadequate iron intake, menorrhagia, GI blood loss, pregnancy/lactation, premature infants, celiac sprue, hemolysis


Clinical findings in iron deficiency anemia

• Microcytic
• Causative: esophageal web, achlorhydria (low stomach acid)
• Associated: glossitis, angular cheilosis, koilonychia (spoon nails)
• Conjunctival pallor, palmar creases, craving (pica) for rice


Lab findings in iron deficiency anemia

• Decreased MCV, serum iron, serum ferritin, iron saturation
• Increased TIBC, RDW, FEP
• Thrombocytosis


Anemia of chronic disease

• Chronic inflammation, alcoholism, malignancy
• Normal or decreased MCV
• Increased serum ferritin, FEP
• Decreased serum iron, TIBC, iron saturation
• Treat with EPO or hepcidin antagonist


Alpha thalassemia

• Black population have 1 deletion on each chromosome
• Southeast Asian population has 2 deletions on one chromosome
• 3 deletions = HbH, causing severe hemolytic anemia
• 4 deletions = Hb Bart, incompatible with life
• Decreased MCV, Hb, Hct
• Increased RBC
• Normal RDW, serum ferritin, FDP
• May show target or teardrop cells


Beta thalassemia minor

• Mild microcytic anemia
• Decreased MCV, Hb, Hct
• Increased RBC
• Normal RDW, serum ferritin, FDP
• Target and teardrop cells present
• Hb electrophoresis: increased HbA2 (2 alpha/2 delta) and HbF


Beta thalassemia major (Cooley anemia)

• Severe hemolytic anemia; RBCs with alpha-chain inclusions removed by splenic macrophages
• Jaundice, increased UCB
• Extramedullary hematopoiesis: hepatosplenomegaly, "hair-on-end" skull XR
• Increased RDW
• Reticulocytes, teardrop cells, Howell-Jolly bodies (nuclear remnants), nucleated RBCs
• Hb electrophoresis: no HbA, only HbA2 and HbF
• Blood transfusion (danger of iron overload, requires chelation) or bone marrow transplant


Sideroblastic anemia

• Alcoholism, B6 deficiency, lead poisoning, XLR inherited
• Deficiency in heme synthesis of developing RBCs; iron accumulates and RBCs die
• Children: abdominal colic, constipation, encephalopathy, growth retardation (lead in epiphyses)
• Peripheral neuropathy, kidney damage, lead lines in guns
• Increased serum iron, iron sat, ferritin; decreased MCV, TIBC


Megaloblastic anemia

• Macrocytic
• Folic acid or B12 deficiency (increased homocysteine levels)
• Impaired DNA synthesis leads to enlarged, nucleated RBCs that are eventually destroyed
• Oval macrocytes
• Pernicious anemia may cause B12 deficiency; Abs vs parietal cells, type 2 hypersensitivity, achlorhydria; yellow skin, associated w/ other autoimmune diseases (test: Abs vs intrinsic factor binding)


Nonmegaloblastic macrocytosis

• Macrocytes round, not oval
• Normal WBCs, platelets
• Liver disease from alcohol: no anemia
• Alcohol alone: mild anemia, reversible


Aplastic anemia

• 15-25 yrs old or >60 yrs old
• Immune destruction of myeloid stem cells; sometimes TERT mutation
• Fever, bleeding, fatigue
• Pancytopenia, reticulocytopenia, hypocellular marrow
• Pure RBC aplasia possible from leukemia drugs, parvovirus


Chronic renal failure

• ACD and decreased EPO
• Burr cells (RBC with undulating membrane)
• Prolonged bleeding time


Extrinsic hemolytic anemia

• RBCs destroyed by macrophages in spleen
• Increased UCB, LDH


Intrinsic hemolytic anemia

• RBCs destroyed in vessel
• Increased plasma and urine Hb, hemosiderinuria


Hereditary spherocytosis

• Autosomal dominant
• Spectrin (membrane protein) defect yields spherocyte RBCs, which are destroyed in spleen
• Jaundice, gallstones, splenomegaly
• Normocytic anemia, increased RDW
• Treat with splenectomy


Hereditary elliptocytosis

• Autosomal dominant
• Membrane protein defect
• May cause mild hemolytic anemia, splenomegaly
• Splenectomy for symptomatic pts


Paroxysmal nocturnal hemoglobinuria

• Acquired stem cell mutation
• Complement-mediated lysis of RBCs, neutrophils, and platelets at night (aided by resp acidosis)
• Possible iron deficiency leading to microcytic anemia, risk of vessel thrombosis, risk for developing AML
• Normocytic anemia with pancytopenia, negative LAP stain, decreased haptoglobin, increased Hb
• Diagnose with flow cytometry
• Treat with corticosteroids, Eculizumab to inhibit terminal complement activation


Paroxysmal cold hemoglobinuria

• Transient hemolytic anemia in kids with measles, mumps, flu, chicken pox; also associated with syphilis
• IgG cold Ab (when moving from cold to warm environment, activates complement)
• Fever, rigor, hemoglobinuria, back/leg/abd pain
• May cause renal failure
• Associated with Raynaud's
• Treat with plasma exchange to remove Ab


G6PD deficiency

• Deficient H2O2 neutralization; it oxidizes Hb, which precipitates in Heinz bodies, which lyse the RBC
• Oxidant stresses include infection, drugs (ex. quinolones), fava beans
• Sudden onset back pain, hemoglobinuria, jaundice
• Normocytic anemia, bite cells


Pyruvate kinase deficiency

• Autosomal recessive
• PEP isn't converted to pyruvate in glycolysis
• Low ATP damages RBC membrane; cell dehydrates, creating echinocytes
• Jaundice, splenomegaly
• Normocytic anemia


Immune hemolytic anemias

• Autoimmune, drug induced, or alloimmune
• IgG hemolysis: spherocytes
• Complement hemolysis
• IgM hemolysis: RBC agglutination
• Jaundice, hepatosplenomegaly, Raynaud's (in cold AIHA)
• Positive Coombs test
• Normocytic anemia
• Treat with corticosteroids, immune suppression, IV IgG (last resort; blocks from host IgG)


Micro- and macroangiopathic hemolytic anemias

• Often caused by aortic valve stenosis
• Micro: thrombi cause RBC fragmentation, schistocytes
• Macro: valve defect damages RBC
• Normocytic anemia (possibly microcytic if longstanding)