Anemia
it is a deficiency of red blood cells (RBCs) and\or haemoglobin ,this
results in a reduced ability of blood to transfer oxygen to the tissue
, causing tissue hypoxia .
Classification of anemia :
(1) According to the reasons that cause anemias , they are classified into 4 types :
a- Haemorrhagic anemia : This results from excessive blood loss e.g.
due to a bleeding peptic ulcer or piles , excessive menstrual bleeding
or bilharzial infection .
b- Haemolytic anemia : This results from excessive breakdown of red
blood cells e.g. due to malaria parasites or lead poisoning .
c- Aplastic anemia : This results from damage of bone marrow as
occurs in severe diseases ( e.g. renal failure ) or as a result of
prolonged exposure to X-ray , atomic radiation , antibiotics or
malignant disease .
d- Deficiency or Nutritional anemia : This results from deficiency
of some dietary factors needed for erythropoiesis e.g. iron deficiency
anemia , pernicious anemia and scurvy anemia ( deficiency of vitamin C )
.
(2) According to blood indices (MCV , MCH , MCHC) , they are classified into 3 types:
a- Normocytic Normochromic anemia : The red cells have normal size
and normal amount of haemoglobin , but their count is below normal .
Causes
b- Microcytic Hypochromic anemia : Both the size and haemoglobin
content of the red cell are decreased , but their count may be normal
Causes
c- Macrocytic Hyperchromic anemia : most cells are larger than normal and contain larger amount of haemoglobin
Causes
(3) Other types of anemia :
it is a deficiency of red blood cells (RBCs) and\or haemoglobin ,this
results in a reduced ability of blood to transfer oxygen to the tissue
, causing tissue hypoxia .
Classification of anemia :
(1) According to the reasons that cause anemias , they are classified into 4 types :
a- Haemorrhagic anemia : This results from excessive blood loss e.g.
due to a bleeding peptic ulcer or piles , excessive menstrual bleeding
or bilharzial infection .
b- Haemolytic anemia : This results from excessive breakdown of red
blood cells e.g. due to malaria parasites or lead poisoning .
c- Aplastic anemia : This results from damage of bone marrow as
occurs in severe diseases ( e.g. renal failure ) or as a result of
prolonged exposure to X-ray , atomic radiation , antibiotics or
malignant disease .
d- Deficiency or Nutritional anemia : This results from deficiency
of some dietary factors needed for erythropoiesis e.g. iron deficiency
anemia , pernicious anemia and scurvy anemia ( deficiency of vitamin C )
.
(2) According to blood indices (MCV , MCH , MCHC) , they are classified into 3 types:
a- Normocytic Normochromic anemia : The red cells have normal size
and normal amount of haemoglobin , but their count is below normal .
Causes
- Excessive haemolysis of red cells
- Bone marrow depression
- Sudden loss of a large volume of blood
b- Microcytic Hypochromic anemia : Both the size and haemoglobin
content of the red cell are decreased , but their count may be normal
Causes
- Myxoedema ( Hypothyroidism)
- Iron Deficiency
c- Macrocytic Hyperchromic anemia : most cells are larger than normal and contain larger amount of haemoglobin
Causes
- Deficiency of vitamin B12 ( which needed for RBC division )
- Deficiency of Folic Acid
(3) Other types of anemia :
- Sickle-cell anemia : is a group of genetic disorders caused by sickle haemoglobin (Hb S )
- Hereditary spherocytosis : Defect in cell membrane of RBCs
- Thalassemia ( Mediiterrraean Anemia ) : the genetic defect results in reduced rate of synthesis of one of globin chains that make HB
G6PD ( glucose-6-phosphate dehydrogenase ) deficiency anemia
: G6PD deficiency is an inherited condition in which the body doesn't
have enough of the enzyme glucose-6-phosphate dehydrogenase , which
helps RBCsfunction normally . this deficiency can cause haemolytic
anemia , usually after exposure to certain medications , foods , or even
infections
