What are the causes for the symptoms of sickle cell anemia?

I need to know this for a case study that i am doing for anatomy/physiology. Sources are needed.

Remember i am looking for the cause of the symptoms. Ex. muscle pain causes by blocked blood vessels….

is this what u need? The red blood cells form into a sickle shape instead of round/flat. They have trouble passing through the smaller blood vessels. The vessel gets blocked and hemorrhages and the skin becomes purple. A transfusion as far as I know is the only remedy.