Which initial investigations should be performed to assess for dysautonomia in patients presenting with orthostatic hypotension?

When assessing for dysautonomia in patients presenting with orthostatic hypotension, the initial investigations primarily focus on confirming the presence of orthostatic hypotension itself, as it is a common manifestation of dysautonomia (Arnold and Raj, 2017).

The initial assessment involves gathering a detailed history and performing a physical examination ¹. Key information to collect includes the circumstances of the event, the person's posture immediately before loss of consciousness, prodromal symptoms (such as sweating or feeling warm/hot), and the appearance and colour of the person during the event ¹. A history typical of postural hypotension includes symptoms like light-headedness, near-fainting, impaired concentration, headaches, dimming or blurring of vision, forceful heartbeats, palpitations, tremulousness, and chest pain, which occur or worsen on standing up and improve by sitting or lying down ¹,².

The primary initial investigation to confirm orthostatic hypotension is the measurement of blood pressure ¹. This should be conducted according to the recommendations for measuring and managing postural hypotension, as detailed in NICE's guideline on hypertension (recommendations 1.1.5 to 1.1.7) ¹.

If blood pressure measurements do not confirm orthostatic hypotension despite the presence of suggestive symptoms, the person should be referred for further specialist cardiovascular assessment ¹.