see also:

• the shocked patient
• hypotension
• postural orthostatic tachycardia syndrome (POTS)
• anorexia nervosa / eating disorders

• postural hypotension is a significant fall in systolic BP upon standing
• it may also have postural tachycardia

• lie patient down for 5 minutes
• measure BP and HR
• have the patient stand up (if safe to do so, provide support if dizzy)
  • if standing is not possible or safe, patient can sit on the side of bed with feet on the floor
• repeat BP and HR at 1 minute and at 3 minutes
• a drop in systolic BP of ≥20 mm Hg (> 30mmHg is often used if patient has baseline hypertension), or in diastolic BP of ≥10 mm Hg, or experiencing lightheadedness or dizziness is considered abnormal
• some patients may only have postural tachycardia
• a more detailed assessment especially for those who cannot stand uses a tilt table

• may be asymptomatic
• usually causes lightheartedness on standing which may result in falls risk or be mistaken for vertigo
• may cause visual disturbance on standing
• may cause pre-syncope or syncope / near syncope
• it may be a precursor to life threatening the shocked patient if due to ongoing blood loss, sepsis, etc

• inadequate blood volume
  • dehydration
    • anorexia nervosa / eating disorders
  • blood loss
  • fluid sequestration eg. gastro-intestinal ileus
• excessive arterial or venous dilatation
  • sepsis / septicaemia
  • anaphylaxis
  • heat illness and heat stroke
  • medications
    • nitrates
    • etc
• impaired autonomic function
  • medications
    • alpha adrenergic blockers
    • beta adrenergic blockers
    • many antihypertensives
    • prochlorperazine
    • chlorpromazine
    • etc
  • postural orthostatic tachycardia syndrome (POTS)
  • autonomic neuropathies
    • see dysautonomia syndromes
    • diabetes
    • Parkinsons
    • etc