It's early in the morning and 20-year-old Aaron Reid looks like he's sleepwalking.
His head nods forward and he shuffles a bit as he heads toward the pediatric clinic at the National Institutes of Health Clinical Center.
Reid, who has been fighting leukemia since he was 9-years old, is experiencing intense pain.
He can't say much at the moment, so his mother, Tracie Glascox, speaks for him. "He's been complaining of pain in his ankles, his knees and his arms," she tells the nurse.