Some people have difficulty mustering an appropriate reflex increase in the activity of the sympathetic nervous system when they stand, causing in them postural hypotension, and perhaps blackout and falls. There are a variety of different disorders where this can happen. We have been cataloguing the individual pathological mechanisms, to devise more effective treatment, in these patients with orthostatic intolerance. The orthostatic intolerance syndrome can occur in patients with degenerative disease of the sympathetic nervous system.
Much more common, however, and in younger people, are disorders involving the function, rather than the structural integrity, of the sympathetic nervous system. Our recent research has been successful in identifying these faults. These have been shown to be, to name two, diminished synthesis of the sympathetic transmitter, noradrenaline and epigenetic (gene control) abnormality in the nerve noradrenaline transporter. We have devised new treatments based on this knowledge, which we are testing.