 There are four different complications that are sometimes also referred to as crises that can occur in patients with sickle cell anemia or sickle cell disease. Number one is vaso-occlusive crisis and that is because of the clumping of the sickle cells in the blood vessels that can then occlude a blood vessel and cause decreased perfusion to a distal part of whatever that blood vessel feeds. The second type of a crisis is an aplastic crisis where the bone marrow now is not able to produce red blood cells and therefore we just don't have these red blood cells available in patients with sickle cell disease so that already have a low number of red blood cells and also red blood cells that don't function properly. Crisis number three would be a sequestration crisis where the spleen gets congested with the sickle red blood cells that are trying to recycle throughout the body and then all these mediators and the volume accumulates in the spleen and the spleen just cannot function right and because of that volume that accumulation of fluid in the spleen the patient overall will become hypovolemic and it can all the way lead to hypovolemic shock. The fourth type of crisis is a hemolytic crisis where these fragile and stiff sickle cells are sent to the liver for recycling because they've broken apart and now the liver becomes congested and is unable to process these fragile and broken apart red blood cells and therefore these red blood cells lies and it can lead to an increase in bilirubin levels. Please head on over to my full YouTube video to check out all the details about sickle cell anemia.