Pathology of Red Blood Cells and Bleeding Disorders (Part 2 of 3) Flashcards
what causes megaloblastic anemia?
impaired DNA synthesis
what happens in the bone marrow as a result of impaired DNA synthesis?
growth factors signal for increased production and marrow hyperplasia occurs, but hematopoiesis is still ineffective
what is the MCV like in megaloblastic anemia?
it is high
what are the characteristics of megaloblastic anemia (HGB, HCT, MCV, and reticulocyte count)
low HGB, low HCT, high MCV, and low reticulocyte count
what does the peripheral blood smear look like in megaloblastic anemia? ( type of anemia, cell shape, neutrophils)
hypoproliferative anemia, macrocytic anemia, ovalocyte shape RBCs, and neutrophil hypersegmentation
what are two common causes of megaloblastic anemia?
B12 and folate deficiencies
what is pernicious anemia?
when lymphocytes are directed against gastric parietal cells, which are responsible for secretion of intrinsic factor and intrinsic factor is required for B12 absorption; it is associated with B12 anemia
what are the results of pernicious anemia?
chronic atrophic gastritis, megaloblastic anemia, atrophic glossitis, spinal demyelination
what neural issues can be seen in pernicious anemia?
paresthesias, gait disturbances, altered vision, taste, smell, dementia, and psychosis
diagnosis of pernicious anemia can involve what? (4)
megaloblastic anemia, low b12, IF antibodies, and high levels of homocysteine/MM Co-A
what could block the metabolism of folate leading to folate deficiency?
methotrexate (inhibits DHF reductase)
diagnosis of folate deficiency can involve? (3)
megaloblastic anemia, low red cell folate, and high levels of homocysteine
what type of anemia does iron deficiency cause?
hypochromic microcytic anemia
what carries iron to the marrow or into storage?
transferrin
in storage sites, what is iron incorporated into?
ferritin
in marrow, what is iron incorporated into?
into Hgb for red cells
the control of iron happens at what level?
at the absorption level
what influences the tipping point between storing the iron or allowing it through the ferroportin channel into the transferrin systemic pool?
hepcidin
what happens when plasma iron is low?
hepcidin backs off and ferroportin can take those iron molecules out of the mucosa and put it into the trasferrin pool
what happens when there is high plasma iron?
hepcidin destroys ferroportin
what does the peripheral smear look like in iron deficiency anemia?
hypoproliferative, microcytic, and hypochromic; anisocytosis
what are the etiologies of iron deficiency anemia?
dietary lack, impaired absorption, increased requirement, and chronic blood loss
what is the first stage of iron deficiency?
reduced ferritin
what are the physical manifestations of IDA?
koilonychia, alopecia, atrophic glossitis, angular cheilitis
what are the iron studies consistent with iron deficiency anemia?
low serum iron, low serum ferritin, increased TIBC, and low hepcidin
what is anemia of chronic disease?
impaired red blood cell production/ iron utilization in chronic illness such as infection, immune diseases, and malignancy
what are the two mechanisms involved in anemia of chronic disease?
inflammatory cytokines increase hepcidin and low erythropoietin
what are the features of anemia of chronic disease?
low serum iron, reduced TIBC, increased serum ferritin, and abundant stainable iron in tissues
what is aplastic anemia most commonly due to?
drugs, irradiation, and viral infection
what rare inherited forms cause aplastic anemia?
Fanconi anemia (DNA repair defect)
how do you make the diagnosis of aplastic anemia?
the presentation will be along the lines of pancytopenia: anemia, thrombocytopenia, and leukopenia
what will the anemia be like in aplastic anemia?
normocytic but no retic count
where do you make the definitive diagnosis of aplastic anemia?
in the bone marrow
what is pure red cell aplasia?
when the bone marrow shoes decreased/abnormal erythroid precursors
when might pure red cell aplasia be seen?
seen in autoimmune phenomena such as thymoma
what is myelophthisic anemia?
space occupation in the marrow (like metastatic cancer, fibrosis, inflammation, necrosis) replace normal hematopoietic cells
what occurs in myelophthisic anemia?
abnormal release of erythroid and granulocyte precursors results in leukoerythroblastosis
