Cardiovascular: Postural Hypotension (brief)

Question 1

what is postural hypotension?

Answer 1

a fall in systolic blood pressure of at least 20 mmHg (at least 30 mmHg in patients with hypertension) and/or a fall in diastolic blood pressure of at least 10 mmHg within 3 minutes of standing.

Question 2

when does postural hypotension become clinically significant?

Answer 2

if it is accompanied by symptoms of cerebral hypoperfusion, which can lead to syncope and falls

Question 3

what is postural hypotension also known as?

Answer 3

Orthostatic hypotension

Question 4

what are some risk factors for postural hypotension?

Answer 4

• Ageing and frailty.
• Medications that affect sympathetic tone e.g. tamsulosin, antihypertensive agents.
• Medications that cause hypovolaemia (diuretics).
• Dehydration.
• Underlying medical conditions that affect autonomic nerve function (e.g., diabetes mellitus, Parkinson’s disease, lewy body dementia, multiple system atrophy).
• Prolonged bed rest.

Question 5

what is hypovolaemia?

Answer 5

decreased blood volume (maybe due to both salt and water loss or a decrease in blood volume)

Question 6

what are some clinical features of postural hypotension?

Answer 6

• Syncope.
• Visual changes.
• Weakness.
• Fatigue.
• Trouble concentrating.
• Pain across the neck and shoulders.
• Increased ventilation and dyspnoea.
• Parkinsonian features (e.g., resting tremor, slowness, paucity of movement, decreased arm swing when walking).
• Unintended weight loss.
• Headache.
• Cerebellar ataxia.
• Erectile dysfunction and lack of ejaculation.

Question 7

which conditions present in a similar way to postural hypotension?

Answer 7

Vasovagal syncope.
Vertigo.
Vestibular hypofunction.
Parkinson’s.
Non-specific falls in older people.
Psychogenic syncope.

Question 8

what investigations would you conduct to confirm a diagnosis of postural hypotension?

Answer 8

Posture test; Blood pressure should be measured supine or sitting and after standing for 3 minutes.

Results: systolic blood pressure falls >20 mmHg (>30 mmHg in patients with hypertension) and diastolic blood pressure falls >10 mmHg within 3 minutes of standing upright.

Question 9

what is the first line treatment for postural hypotension?

Answer 9

eliminate aggravating factors and institute lifestyle changes.

Education, Avoid triggers, Advise the elderly to stand slowly, Raise the head of the bed, Morning dose of caffeine.

Question 10

what medications can induce or aggravate postural hypotension?

Answer 10

mitriptyline and other antidepressants, diuretics and other antihypertensive agents, alpha-blockers, sildenafil and other phosphodiesterase-5 inhibitors

• should all be carefully reviewed before removed

Question 11

what is the second line treatment for postural hypotension?

Answer 11

mineralocorticoid therapy and volume expansion.

fludrocortisone: 0.1 to 0.2 mg orally once daily and sodium chloride: 1 g orally with each meal.

NB: fludrocortisone should be used with extreme caution as it results in hypertension when supine, promotes cardiac fibrosis, and may accelerate progression of renal deterioration.

Question 12

what is the third line treatment for postural hypotension?

Answer 12

Short-acting pressors or droxidopa.

midodrine: 2.5 mg orally three times daily when required initially, increase according to response, maximum 30 mg/day or droxidopa: 100 mg orally three times daily initially (morning, midday, and late afternoon at least 3 hours before bedtime), increase gradually according to response, maximum 1800 mg/day.

Question 13

what are some complications of postural hypotension?

Answer 13

stroke
falls
syncope

Question 14

what signs on examination may you find in an individual with postural hypotension?

Answer 14

Resting tachycardia or impaired heart rate variation / weight loss.