occure due to decrease in RBCs count or haemoglobin concentration or
both of them & it can be classified into two categories:
A)due to decrease in number of RBCsbut cells are normal in shape and size (normocytic normochromic )
this is due to exessive loss of blood due to accidents,peptic ulcer,belhariziasis,minstruation,....
due to damage of bonemarrow that cause loss in number of RBCs ths occure due to renal failure,radiation,antibiotics,....
due to incompatable blood transfusion or adminstration of antimalarian drugs
-low folic acid "macrocytic anaemia"
-low iron "macrocytic anaemia "
-low vitamine B12 "pernacious anaemia "
-low vitamine C"scarry anaemia"
B)change in shape of cells
a) normocytic normochromic anaemia
b)microcytic hypochromic anaemia (RBCs small in size with low content of Hb or absence of it )
c)macrocytic hyperchromic anaemia (RBCs large in size & filled with Hb )
A)due to membrane problem
B)due to Hb problem
-sickled cell anaemia