The patient is a 20-year-old male with sickle cell disease who presents with several chronic and acute complications. He has a history of delayed puberty, joint pain, weakness and cough. Examination reveals decreased growth, severe anemia, leg ulcers, enlarged spleen and fever. Laboratory tests show hemoglobin of 8g/dL and reticulocyte count of 25%. The most probable cause of the patient's problems is sickle cell disease and its associated complications. The patient is at risk for further complications such as acute chest syndrome, stroke and infection due to his condition.