Anemias Of Decreased RBC Production ( Hypoproliferative Anemias) Flashcards
What are the general features of hypoproliferative anemias?
Heterogenous
Low reticulocyte count
Can have extrinsic or intrinsic causes
Subclassified by morphology
What are the characteristics of microcytic hypochromic anemia?
Normal DNA synthesis
Normal nuclear maturation
Decreased RBC hemoglobin production
Cytoplasmic maturation defect
What are the causes of microcytic hypochromic anemia?
1-Disorders of metabolism: iron deficiency, chronic disease
2-Disorders of heme synthesis: sideroblastic anemia
3-Disorders of globin chain synthesis: thalassemias
What are the main causes of iron deficiency anemia?
1-Dietary deficiency-MC in children(breast milk has poor iron)
2-Impaired absorption (sprue, celiac)
3-Increased requirements ( growing children, pregnancy)
4-Chronic blood loss- MC in adults
Iron deficiency in post menopausal women and adult men is due to chronic blood loss until proven otherwise
What is the normal iron metabolism?
Iron is absorbed in the duodenum
Ferroportin transports iron to blood
In blood iron bind to transferrin
Iron is stored by binding to ferritin or hemosiderin
What are the physical findings suggestive of iron deficiency ?
Koilonychia- spooning of fingernails Alopecia Atrophic glossitis Atrophic gastritis Pica- unusual food cravings
What are the findings in the peripheral blood smear in iron deficiency?
Microcytic hypochromic cells Anisocytosis Poikilocytosis Low reticulocyte count Mild thrombocytosis
How to diagnose iron deficiency ?
Decreased serum iron and saturation%
Increased TIBC
Decreased serum ferritin (storage iron)
High serum soluble transferrin receptor
What are the characteristics of anemia of chronic disease?
Second only to iron deficiency in incidence
Immune driven cytokine response causing disturbance in iron homeostasis and inhibition of bone marrow
What are the findings in peripheral blood smear of anemia of chronic disease ?
Microcytic hypochromic or normocytic normochromic anemia
Normal RDW
Low reticulocyte count
No characteristic morphologic features
How to diagnose anemia of chronic disease?
Decreased serum iron and % saturation
Decreased TIBC
Increased bone marrow iron
Normal soluble serum transferrin receptor
What are the characteristics of sideroblastic anemia?
Abnormal iron metabolism within the RBC itself
Iron swells and distorts the mitochondria
Ringed sideroblasts
How to diagnose sideroblastic anemia?
Increased serum iron and % saturation
Decreased or normal TIBC
Increased marrow iron
Variable soluble serum transferrin receptor
What are the 2 classifications of macrocytic anemia?
Megaloblastic marrow
Non megaloblastic marrow
What are the causes of megaloblastic marrow in macrocytic anemia?
Folate deficiency
Vitamin B12 deficiency
Copper deficiency
Drug effect
What are the causes of non megaloblastic marrow in macrocytic anemia?
Drug effect
Alcohol abuse
Hypothyroidism
Aplastic anemia
What are the characteristics of megaloblastic anemia?
Most common causes are B12 or folate deficiency
Results in defective nuclear maturation
Abnormally large peripheral blood erythrocytes and bone marrow erythroblasts
Megaloblastic myeloid precursors
Nuclear:cytoplasmic dyssynchrony of cell maturation
What are the findings in peripheral blood smear of megaloblastic anemia?
Rare teardrop cells
Hypersegmented neutrophils
Oval macrocytes
What is the bone marrow morphology in megaloblastic anemia?
Hypercellular marrow
Ineffective hematopoiesis
Megaloblastic features
What are the laboratory diagnostic findings in megaloblastic anemia?
Serum B12 is decreased and somewhat decreased in folate deficiency
Serum folate fluctuates with diet so it is more accurate after 12 hours of fasting- normal or increased in B12 deficiency, decreased in folate and mixed deficiency
Methyl malonic acid is normal in folate and elevated in B12 and mixed deficiency
RBC folate is decreased in all
What are the clinical features of aplastic anemia?
May occur at any age, either sex
Insidious onset
Pancytopenia usually develops
Can be acquired ( more common) idiopathic or inherited (Fanconi anemia,telomerase defects)
What are the characteristics of Fanconi anemia?
Autosomal recessive congenital Defect of DNA repair Has bone, skin and renal abnormalities Mental retardation Usually die of marrow failure If live long enough, at risk of leukemia
What are the characteristics of pure red cell aplasia?
Primary marrow disorder in which only erythroid progenitors are suppressed
Causes can be neoplasms (thymoma),drug exposures,autoimmune diseases, parvovirus B19 infection
What are the characteristics of inherited red cell aplasia: Blackfan-Diamond syndrome?
Bone marrow grossly reduced or absent erythroid precursors
Granulopoiesis is unaffected
No giant erythroblasts
Defect in generation of ribosomes in RBC precursors
