SICKLE CELL PATHOPHYSIOLOGY B.PHARM 2ND SEM.pptx

PATHOPHYSIOLOGY B.PHARM 2ND SEM

1. DEFINITION Sickle-cell disease (SCD) is a group of blood disorders typically inherited from a person's parents. The most common type is known as Sickle-cell anaemia (SCA). It results in an abnormality in the oxygen-carrying protein, haemoglobin present in RBCs. This leads to a rigid, sickle-like shape under certain circumstances. Problems typically begin around 5-6 months of age. The problems involve anaemia , swelling in hands and feet, bacterial infections etc.

2. ETIOLOGY Normal RBCs are quite elastic, which allows them to deform while passing through capillaries. In sickle cell anaemia , low oxygen tension promotes sickling of RBCs and repeated episodes of sickling damage the cell membrane leading to decrease in cell elasticity.

3. The cells return to normal shape when oxygen tension is restored . Rigid RBCs are unable to pass through narrow capillaries, leading to vessel occlusion and ischaemia .

4. The actual anaemia is caused by haemolysis . Healthy RBCs typically function for 90-120 days; while sickle cells last only for 10-20 days.

5. SYMPTOMS Fatigue and Anemia Pain Crises and Dactylitis (swelling and inflammation of the hands and/or feet) Arthritis Bacterial Infections Splenic sequestration (sudden pooling of blood in the spleenand Liver Congestion )

6. Lung and Heart Injury Leg Ulcers Aseptic necrosis and bone infarcts (death of portions of bone) Eye damage

7. PATHOPHYSIOLOGY The loss of red blood cell elasticity is central to the pathophysiology of sickle cell anemia. Normal red blood cells are quite elastic, which allows the cells to deform to pass through capillaries.

8. In sickle cell anemia, low-oxygen tensions promotes red blood cell sickling and repeated episodes of sickling damage the cell membrane and decrease the cell's elasticity. These cells fail to return to normal shape when normal oxygen tension is restored

9. As a consequence, these rigid blood cells are unable to deform as they pass through narrow capillaries, leading to vessel occlusion and ischaemia .