Orthostatic Hypotension

Question 1

Define orthostatic hypotension

Answer 1

1. Excessive fall in BP when upright position assumed
2. Abnormal BP regulation
   A. Due to another disorder

Question 2

How much does the systolic bp drop in orthostatic hypotension?

Answer 2

> 20 mmHg

Question 3

How much does the diastolic bp drop in orthostatic hypotension?

Answer 3

10 mm/Hg

Question 4

What are the sxs of orthostatic hypotension?

Answer 4

1. Faintness
2. Lightheadedness
3. Dizziness
4. Blurred vision
   A. Can cause falls, syncope or generalized seizures
5. Occurs within sec/min of standing
6. Resolves with lying down

Question 5

What normally happens to blood distribution, venous return, CO, and BP when standing?

Answer 5

1. Normally standing pools ½ - 1L blood in leg/trunk veins
   A. Leads to ↓ venous return
   B. ↓ CO and BP

Question 6

What is the physiologic response to standing?

Answer 6

1. Baroreceptors (aortic arch & carotid bulbs) activate autonomic reflexes to return BP to normal
2. Sympathetic system ↑ HR, contractility and vasomotor tone in veins
3. Parasympathetic inhibition also ↑ HR

Question 7

What is the physiologic response to prolonged standing?

Answer 7

1. Activates renin-angiotensin-aldosterone system and ADH secretion causing Na and H2O retention
   A. ↑ blood volume, CO

Question 8

What is the pathophys of orthostatic hypotension?

Answer 8

1. Physiologic mechanisms may be inadequate to restore low BP after standing if:
   A. Autonomic response impaired by disorders or drugs
   B. Myocontractility depressed
   C. Vascular responsiveness depressed
   D. Hypovolemia

Question 9

What is the etiology of acute orthostatic hypotension?

Answer 9

1. Hypovolemia (most common)
A. Fluids, blood loss
2. Drugs
3. Prolonged bed rest
4. Adrenal insufficiency

Question 10

What is the etiology of chronic orthostatic hypotension?

Answer 10

1. Age related
2. Drugs
3. Autonomic dysfunction
   A. Parkinson’s Dz

Question 11

What questions need to be asked when investigating the history of a pt with orthostatic hypotension?

Answer 11

1. Duration and severity of sxs
2. Association with syncope or falls
3. Known triggers
   A. Drugs
   -Alpha blockers (peripheral)
   -Diuretics
   -Nitrates
   -CCB
   B. Prolonged bed rest
   C. Fluid loss

Question 12

If orthostatic hypotension is asst with aphasia, dysarthria, facial droop and hemiparesis, what may be the underlying cause?

Answer 12

Stroke

Question 13

If orthostatic hypotension is asst with cardiac murmur or gallop, what may be the underlying cause?

Answer 13

CHF, MI

Question 14

If orthostatic hypotension is asst with cogwheel rigidity, festinating gait, lack of truncal rotation, and masked facies, what may be the underlying cause?

Answer 14

Parkinson’s disease

Question 15

If orthostatic hypotension is asst with confusion, dry mouth, dry tongue, longitudinal tongue furrows, speech difficulty, sunken eyes, and upper bdy weakness, what may be the underlying cause?

Answer 15

Dehydration (in older pts)

Question 16

If orthostatic hypotension is asst with decreased libido, impotence in men, urinary retention and incontinence in women, what may be the underlying cause?

Answer 16

Autonomic failure

Question 17

If orthostatic hypotension is asst with dependent lower extremity edema and stasis dermatitis what may be the underlying cause?

Answer 17

Right sided congestive heart failure, venous insufficency

Question 18

How is bp measured if orthostatic hypotension is suspected?

Answer 18

1. Check BP & HR after 5 min supine 2. BP 1 min sitting
2. BP 1 min standing OR (BP & HR 1-3 min standing)

Question 19

What does hypotension without increased hr indicate?

Answer 19

Autonomic impairment

Question 20

What does hypotension with marked increased hr indicate?

Answer 20

HR (>100 bpm or ↑ 30 bpm)

Hypovolemia

Question 21

What findings may be present on a skin exam in a pt with orthostatic hypotension?

Answer 21

1. Skin/mucus membranes
   A. Dehydration
   B. Pigmentation changes
   -Hyperpigmentation – Addison disease

Question 22

What findings may be present on a rectal exam in a pt with orthostatic hypotension?

Answer 22

Positive heme in stool

Question 23

What findings may be present on a neuro exam in a pt with orthostatic hypotension?

Answer 23

1. GU and rectal reflexes evaluate autonomic function
2. Abnormal strength, sensation and DTR’s
   A. Peripheral neuropathy

Question 24

What are red flags on the PE?

Answer 24

1. Blood/heme (+) stool

2. Abnormal neurologic exam

Question 25

What dx studies should be performed on a pt with orthostatic hypotension?

Answer 25

1. EKG 2. BUN, Cr, lytes, glucose 3. CBC 4. Bedside cardiac monitoring A. R/O arrhythmia 5. Tilt table testing

Question 26

Why is tilt table testing indicated?

Answer 26

1. High probability of orthostatic hypotension despite an initial negative evaluation (e.g., Parkinson disease) 2. Patients with significant motor impairment that precludes them from having standing vital signs obtained

Question 27

What are normal tilt table results?

Answer 27

1. HR increases by 10-15 bpm | 2. DBP increases by 10 mmHG or more

Question 28

What are tilt table results that indicate dysautonomia?

Answer 28

1. Immediate and continuing drop in BP | 2. No compensatory increase in HR

Question 29

What are tilt table results that indicate neurocardiogenic syncope?

Answer 29

1. Symptomatic, sudden drop in BP 2. Simultaneous bradycardia 3. Occurs after 10 mins or more of testing

Question 30

What are the non-medical treatment options for orthostatic hypotension?

Answer 30

1. Reduce or D/C offending medication 2. Change positions slowly 3. Adequate hydration 4. Limit or avoid alcohol 5. Regular exercise A. Promotes vascular tone → ↓ venous pooling 6. Elderly - avoid prolonged standing 7. Support pantyhose A. ↑ venous return, CO, & BP after standing 8. Increase Na intake A. If no HTN or CHF

Question 31

What are the medical treatment options for orthostatic hypotension?

Answer 31

1. Fludrocortisone (Florinef) 0.1 mg 2. Midodrine (Orvaten, ProAmatine) 3. Pyridostigmine (NAPPS, Mestinon)

Question 32

What is the class and moa of Fludrocortisone (Florinef)? How is it dosed?

Answer 32

1. Mineralcorticoid 2. Causes Na retention 3. 0.1 mg-0.2 mg PO qd A. Titrate weekly until trace of pedal edema B. Max 1 mg/day

Question 33

What is the class and moa of Midodrine (Orvaten, ProAmatine)? How is it dosed?

Answer 33

1. Inotrope/Pressor 2. Stimulates alpha-1 adrenergic receptors 3. Causes arterial and venous constriction 4. 2.5 mg PO tid A. Titrate weekly B. Max 10 mg PO tid

Question 34

What is the class and moa of Pyridostigmine (NAPPS, Mestinon)? How is it dosed? What else is it used for?

Answer 34

``` 1. Used for neurogenic orthostasis A. Myasthenia gravis 2. Cholinesterase inhibitor 3. Affects autonomic response 4. Increases total peripheral resistance 5. 30 mg PO bid-tid A. Titrate weekly B. Max 60 mg PO tid ```