Do strokes cause PD?

Strokes are caused by blockage of arteries: the “pipes” through which blood flows. Arteries harden in older people, especially if they have diabetes, high blood pressure, high cholesterol, and if they smoked. If an artery closes, and if there are no arteries in the neighborhood that can replace it, the region of the brain the artery supplies is infracted: it dies. Unlike PD, where symptoms appear slowly and progress, in a stroke symptoms appear suddenly and do not progress. In PD symptoms do not go away, whereas in a stroke they may. Strokes do not cause PD, but occasionally a person may have many small strokes in the corpus striatum, the region of the brain to which fibers from the substantia nigra go. Strokes in the striatum may cause symptoms of PD. These symptoms do not respond well to PD drugs. The strokes can be seen on an MRI scan (magnetic resonance imaging). This is called “vascular PD.” Sometimes strokes and PD coexist: having PD does not protect you from having strokes, and vice versa.