Sweep 1.2 Flashcards
• Extrinsic defect hemolytic anemias-
antibody, mechanical trauma, acquired
o Autoimmune hemolysis-
extravascular hemolysis, patient makes antibodies to their own RBCs. phagocytosis of antibody coated RBC cand lead to partial loss of RBC membrane→ spherocytes
• Pernicious anemia- caused by antibodies to
parietal cells and intrinsic factor
o Absorption of B12 requires
intrinsic factor
• Vitamin B12 and Folate deficiency-
Megaloblastic Anemia;
need vitamin B12 and folate to make
thymidine, deficiency leads to delay in mitotic division, nuclear size increases, end result is huge red cell precursor (megaloblast).
Vitamin B12 and Folate deficiency: Accumulation of
megaloblasts in bone marrow, less RBCs released, decreased production of mature RBCs→ impairment of DNA synthesis is systemic and affects other rapidly dividing cells
• Aplastic anemia- production of all
cellular elements of blood is markedly decreased (pancytopenia)
Aplastic anemia: >50% of cases are
idiopathic but hepatitis, drugs and toxins have been implicated
Aplastic anemia: Theories:
•
Acquired defect in stem cell production, suppression of stem cells by T lymphocytes
Aplastic anemia: o Clinically-
weakness, fatigue, leukopenia, decreased platelets
Aplastic anemia: o Therapy-
bone marrow transplant, successful in pts <40yrs old
• Myeloplastic anemia-
normal hematopoietic cells in marrow crowded out by tumor or fibrosis (usually multiple myeloma or metastatic cancer)
• Polycythemia-
increase in red cell mass
o Absolute polycythemia-
can be a primary or secondary phenomenon
• Primary absolute polycythemia-
non-regulated proliferation of red cells and myeloid cells (polycythemia vera);
Primary absolute polycythemia is a
stem cell disorder associated with normal or low levels of erythropoietin
• Primary absolute polycythemia; Polycythemia vera can cause
neurologic and visual abnormalities due to sludging of red cells in capillaries→ treat with phlebotomy
• Secondary absolute polycythemia→
living at high altitude, cyanotic heart disease, pulmonary disease, due to stimuli that increase erythropoietin