describe megaloblasic anemia
caused by a B12/folate deficiency. both are involved directly or as cofactors for thymidine production. impaired dna synthesis causes a delay in mitotic division causing increased nuclear size but normal RNA synthesis and cytoplasmic maturation. the end result is an abnormally large red cell precursor (megaloblast), decreased production of mature RBCs and abnormally large red cells. the megaloblasts accumulate in the bone marrow, releasing too few RBCs into peripheral blood and causing anemia.