Diagnosis and investigation

• history and examination - the key feature of symptoms related to orthostatic hypotension is that they are precipitated by head-up postural change and relieved by lying flat. Other factors may influence symptoms e.g. speed of positional change, coughing. There may be a history of impairment of other organs under autonomic control e.g. lack of sweating suggests a neurogenic cause. A detailed drug history should be taken
  
  
• the differential diagnosis includes carotid sinus syncope
  • Carotid sinus syndrome
    
    • causes syncope, near-syncope, or unexplained falls due to carotid sinus hypersensitivity
    • like postural hypotension, it is more common in older people and is difficult to distinguish clinically
    • tilt-table testing may help in a diagnosis - this is undertaken via a specialist e.g. cardiologist
• degree of orthostatic hypotension should be determined by measurement of blood pressure and heart rate whilst the patient is lying flat and either standing upright or at a 45 degree angle
  
  
• investigations include:
  • blood tests - full blood count if the patient has chronic bleeding or anaemia, urea and electrolytes, HbA1c for diabetes, vitamin B12
  • ECG - if an arrythmia is suspected
  • echo - if a structural heart problem is suspected
    
    
• referral to a specialist if symptoms are not controlled or are persistent and frequent, or if the cause is unexplained
  • consideration of specialist referral is based on the patient's age, symptoms, and medical conditions
    • for example
      • a young patient with repeated unexplained syncopal symptoms and palpitations would be referred to a cardiologist
      • an older patient with bradykinesia and a shuffling gait would be referred to a neurologist, and an elderly frail patient with multimorbidity and polypharmacy with recurrent falls would be referred to a geriatrician (2)

Reference:

1. Low VA, Tomalia TA. Orthostatic Hypotension: Mechanisms, Causes, Management.J Clin Neurol. 2015 Jul; 11(3): 220-226.
2. Gilani A et al. Postural Hypotension. BMJ 2021;373:n922 http://dx.doi.org/10.1136/bmj.n922