Clinical approach to autonomic dysfunction.

Patients with autonomic dysfunction may present with a variety of seemingly unrelated symptoms, both generalised and involving specific systems, including fatigue, difficulty concentrating, orthostatic intolerance, palpitations, constipation or diarrhoea, early satiety, urinary retention or incontinence and erectile dysfunction. Failure to connect the diverse symptoms with a single underlying mechanism may lead to incorrect diagnoses, inappropriate interventions and frustration on the part of both doctors and patients. We describe recent developments in the understanding of the pathophysiology of autonomic dysfunction, including the link between the autonomic and immune systems resulting in the 'inflammatory reflex'. We then provide a rationale to guide the management of patients exhibiting features of autonomic dysfunction, including postural tachycardia syndrome.