Causal Relationships in Health and Disease
In July of 1998, a 55-year-old man developed a new and unusual appearing rash on both of his arms. His symptoms began approximately 3 weeks earlier, when he first experienced weakness in his left hand. His physician ordered a magnetic resonance imaging (MRI) scan of the brain, which was normal. Suspecting that the man’s symptoms were caused by a transient ischemic attack, or mini-stroke, the physician prescribed aspirin.