Postural hypotension

Question 1

What is the definition of postural hypotension?

Answer 1

When someones blood pressures falls by more than 20/10mmHg within 3 mins of standing compared to when they sit/lie down

Question 2

What is the pathology of postural hypotension?

Answer 2

• Normally the blood pressure of a person rises if someones stands up due to ↑ venous return/venoconstriction
• Loss of extracellular fluid prevents this = ↓ BP
• Baroreflex mechanism that controls heart rate and vascular resistance declines with age

Question 3

What are the risk factors/aetiology of postural hypotension?

Answer 3

• Elderly
• Diabetes = hypovolaemia
• Systemic amyloidosis = hypovolaemia
• Age = hypovolaemia
• Parkinson’s disease
• Tricyclic antidepressents – interference with autonomic function
• Nitrates – interference with peripheral vasoconstriction
• Ca channel blockers – interference with peripheral vasoconstriction
• Diuretics = hypovolemia
• Prolonged bed rest

Question 4

What are the signs/symptoms of postural hypotension?

Answer 4

• JVP – when lying flat
• Cold skin
• Empty peripheral veins
• Tachycardia
• Dizziness
• Headache
• Blurred vision
• Fatigue
• Syncope
• Nausea

Question 5

What investigations are carried out for suspected postural hypotension?

Answer 5

• Lying and standing BP

Question 6

What is the pharmacological treatment for postural hypotension?

Answer 6

• Midodrine

Question 7

What is the non pharmacological treatment for postural hypotension?

Answer 7

• Manage underlying cause
• Drink more water
• Compression stockings
• Physical counterpressure manoeuvres
• Sit up and then change position slowly