Clinical syndromes with vasoconstrictor response.

Vasospasm implies reversible vasoconstriction that may diminish blood flow to the perfused tissues followed by an ischaemia of varying severity. The exact pathophysiology of the condition remains unknown to this day. Vasospasms are not only present in Raynaud's disease, migraine, Prinzmetal's variant angina, visual field defects and partially in low-tension glaucoma, but may also be involved in the pathogenesis of Crohn's disease. Vasospastic diseases may result from more than one mechanism. It is difficult to determine which of the underlying abnormalities is the most important in vasospastic syndromes of different vascular beds.