Postural/orthostatic hypotension

Question 1

Define hypotension.

Answer 1

Sudden drop in blood pressure when you stand from a seated or prone (lying down) position.

A fall in systolic BP of at least 20mmHg (30mmHg in those with HTN). AND/OR, a fall in diastolic BP of at least 10mmHg within 3 minutes of standing.

Question 2

Who is affected?

Answer 2

Common problem in frail, elderly people.

Even higher prevalence if the older person is in a nursing home/hospital.

Question 3

What is the pathophysiology of hypotension?

Answer 3

· When a healthy person stands, 700ml of blood pools in the leg veins and lower abdominal veins.
· Venous return to the heart decreases, resulting in a transient decline in cardiac output.
· This leads to baroreflex-mediated sympathetic activation, with an increase in cardiac stroke volume and peripheral vasoconstriction.
· These rapid haemodynamic changes prevent BP from falling.
· Failure of these mechanisms cause orthostatic hypotension.

Question 4

OH can be triggered by which type of medications?

Answer 4

· Alpha blockers used for BPH.
· Diuretics.
· Tricyclic antidepressants.
· Anti-hypertensives.

Question 5

What other circumstances can OH be triggered by?

Answer 5

· Volume depletion.

· Physical deconditioning due to prolonged bed rest.

Question 6

List the common risk factors that can cause OH.

Answer 6

· Frailty and physical deconditioning.
· Medications that impair sympathetic tone.
· Volume depletion.
· Autonomic neuropathy (diabetes).
· Parkinson’s disease and Lewy body dementia - protein deposits in autonomic nerves.

Question 7

What are the typical signs and symptoms of OH?

Answer 7

· Postural light-headedness, dizziness. syncope and other symptoms of cerebral hypoperfusion.
· Abnormal GI motility.
· Signs of an underlying cause such as Parkinsonian features.

Question 8

What are the typical presenting symptoms of cerebral hypoperfusion?

Answer 8

Visual changes, weakness, fatigue, trouble concentrating and pain across the neck and shoulders .

Question 9

What investigations would you request if you suspected a patient had OH?

Answer 9

· Posture test.
· Tilt-table test.
· 24hr BP monitoring.

Question 10

List some differentials.

Answer 10

· Vasovagal syncope.
· Vertigo.
· Non-specific falls in older people.

Question 11

What is the treatment plan for patients suffering from OH?

Answer 11

· 1st line - eliminate aggravating factors and institute lifestyle changes.
· Adjunct - Mineralocorticoid therapy and volume expansion.
· Adjunct - Short-acting pressors and droxidopa.
· Adjunct - Correction of anaemia.

Question 12

What complications can arise?

Answer 12

· Falls.

· Super hypertension.