What medical are caused by sickle cell disease???

Consequences

Infections. In general, both children and adults with sickle cell anemia are more vulnerable to infections and have a harder time fighting them off. This is the result of spleen damage from sickled red cells, thus preventing the spleen from destroying bacteria in the blood. Infants and young children, especially, are susceptible to bacterial infections that can kill them in as little as 9 hours from onset of fever. Pneumococcal infections used to be the principal cause of death in children with sickle cell anemia until physicians began routinely giving penicillin on a preventive basis to those who are diagnosed at birth or in early infancy. 

Stroke. Defective hemoglobin damages the walls of red blood cells, causing them to stick to blood vessel walls. The resulting narrowed or blocked small blood vessels in the brain can lead to serious, life-threatening strokes, primarily in children. 

Acute chest syndrome. Similar to pneumonia, this life-threatening complication is caused by infection or trapped sickled cells in the lung. It is characterized by chest pain, fever, and an abnormal chest X ray.(genomics.energy.gov, Jeniffer Bownas, May 5, 2005)

The blockage of blood flow caused by sickled cells also causes damage to most organs including the spleen, kidneys and liver.(The sickle cell disease association of America, In, 2005)

http://www.ornl.gov/sci/techresources/Human_Genome/posters/chromosome/sca.shtml

http://www.sicklecelldisease.org/about_scd/faqs.phtml#top