Why does sickle haemoglobin cause problems?
The chemical change in sickle haemoglobin (HbS) affects the protein in such a way that when oxygen is removed, molecules of HbS tend to stick together producing long cables or filaments which deform the red cells to the sickle shape. The abnormal shape and increased rigidity of these sickled cells leads to a tendency to block the flow in small blood vessels and to their destruction. These two processes lead to the main problems of sickle cell disease. The increased blood destruction leads to anaemia and the increased production of bilirubin results in jaundice and the formation of gallstones. Obstruction of blood flow in small blood vessels produces tissue damage and pain and may occur anywhere in the body but especially in the bones, lungs, brain, eyes, and spleen.
