Orthostatic Hypotension

Definition

• an abnormal drop in BP on standing from lying and further defined as:
  • a fall in sBP of at least 20mmHg, or below 90mmHg, with or without symptom
  • a fall in dBP of 10mmHg with symptoms

Patient needs to be lying for 5mins, then BP measured after standing for 1min and then again at 3mins

Causes

• Neurological:
  • neurodegenerative diseases eg Parkinsons and Parkinson-plus syndromes, some dementia
  • pure autonomic failure (PAF) – Bradbury-Eggleston syndrome
  • secondary to diabetes, vitB deficiency, renal failure, amyloidosis, HIV other autoimmune
• Other:
  • volume depletion – dehydration, anaemia
  • alcohol and drugs/medications
  • cardiovascular disease, adrenal insufficiency, sepsis
  • ageing, idiopathic

Investigation

• baseline Ix – electrolytes, FBC, ECG, Glu
• other - appropriate to likely/possible underlying cause
• may need Tilt Testing to confirm

Management

• treatment of primary cause if known and relevant
• non pharmacological measures to consider first:
  • rehydration when appropriate
  • may need to add salt to diet – caution in Heart Failure or Renal Failure
  • compression stockings
  • education regarding exercise, diet, care with changes in postion
  • review medications
• Pharmacological (either or in combination):
  • Fludrocortisone – 100mcg (>65yo 50mcg) nocte initially
  • Midodrine – 2.5mg tds up to 10mg tds