Anaemia is a blood disorder involving a reduction in the oxygen-carrying capacity of the blood resulting from a deficiency in the number of red blood cells or a deficiency in the quantity of hemoglobin (which carries oxygen) in red blood cells. The main defect that arises from anaemia is a lack of oxygen reaching the body's cells. All cells require oxygen in order to function properly.
The most common symptoms of anaemia are paleness of the lips, fingernails, palms and eyelids; severe fatigue; and weakness.
There are many different types of anaemia:
Iron deficiency anaemia is the most common form of anaemia. It occurs from lack of iron.
Haemolytic anaemia occurs from abnormal and premature destruction of red blood cells. It is often congenital.
Haemorrhagic anaemia occurs from rapid loss of blood.
Hypochromic anaemia occurs from a decrease in the ratio of weight of haemoglobin to the weight of the red blood cell (i.e. a lack of haemoglobin in red blood cells).
Macrocytic anaemia results from the presence of abnormally large red blood cells. This form of anaemia commonly occurs during pregnancy.
Megaloblastic anaemia results from the presence of megaloblasts in the blood.
Methemoglobinaemia results from the conversion of haemoglobin in red blood cells to a toxic compound named methaemoglobin.
Pernicious anaemia results from a deficiency of vitamin B12.
Sickle cell anaemia results from defective haemoglobin molecules causing red blood cells to have a twisted sickle shape instead of their usual round shape.
Sideroblastic anaemia is characterized by the presence of abnormal, ringed sideroblasts.
Folic acid anaemia results from lack of folic acid.
