DSA 27 Autonomic Dysfunction

Question 1

is there a compensatory increased heart rate in neurogenic orthostatic hypertension?

Answer 1

no, indicating that there is something neurologically wrong

Question 2

what is an active compensatory mechanism in patients with non-neurogenic orthostatic hypertension?

Answer 2

pulse rate will increase

Question 3

what are some diseases that can cause orthostatic hypotension?

Answer 3

multiple system atrophy, peripheral nerve dysfunction

Question 4

what are the two main symptoms of MSA?

Answer 4

Parkisonian-like symptoms and cerebellar dysfunction

Question 5

what are some symptoms of peripheral nerve dysfunction?

Answer 5

stock and glove sensory loss and peripheral weakness

Question 6

subacute or chronic reason for orthostatic hypotension due to peripheral nerve dysfunction?

Answer 6

diabetic polyneuropathy

Question 7

acute reason for orthostatic hypotension due to peripheral nerve dysfunction?

Answer 7

GBS

Question 8

Riley-Day familial dysautonomia

Answer 8

causes orthostatic hypotension associated with peripheral nerve dysfunction

Question 9

what are the key physical findings for Horner’s syndrome?

Answer 9

ptosis, anhydrosis, miosis (think PAM is Horny)

Question 10

CN III lesion

Answer 10

mydriasis (dilation)

Question 11

what do you expect to see if orthostatic hypotension is being caused by autonomic dysfunction?

Answer 11

the heart rate will not show the usual compensatory increase, i.e. the baroreceptor reflex is “off”

Question 12

what is amyloidosis?

Answer 12

rare disease that results from accumulation of amyloid (misfolded proteins)

Question 13

what is acute intermittent porphyria?

Answer 13

rare autosomal dominant metabolic disorder affecting the production of heme

Question 14

define orthostatic hypotension

Answer 14

drop in systolic BP >20mmHg and/or drop in diastolic BP >10mmHg within 3 minutes of standing from a supine position

Question 15

what might be a cause of orthostatic hypotension in an older patient if there is NO compensatory increase in heart rate?

Answer 15

orthostatic hypotension associated with brain disorder. prototype is multiple system atrophy/degeneration

Question 16

what causes ptosis in Horner’s syndrome?

Answer 16

muller’s muscle is a smooth muscle in the upper eyelid innervated by the autonomic nervous system. sympathetic denervation of muller’s muscle causes ptosis.

Question 17

what is autonomic disturbance causing Horner’s syndrome?

Answer 17

sympathetic damage resulting in unopposed parasympathetic discharge. this then causes constriction

Question 18

where can the lesion be causing Horner’s syndrome?

Answer 18

hypothalamus, superior cervical ganglion, long ciliary nerve

Question 19

what in a patient’s history would lead you to suspect hypovolemia?

Answer 19

no family history, no sign of autonomic neuropathy, compensatory tachycardia

Question 20

______(parasympathetic/sympathetic) fibers in CN 3 are located peripherally. significance?

Answer 20

parasympathetic. receive blood supply from anastomotic plexus so relatively immune to ischemia. more vulnerable to compression

Question 21

______(parasympathetic/sympathetic) fibers in CN 3 are located interiorly. significance?

Answer 21

sympathetic. receive blood supply from small penetrating arterioles. vulnerable to ischemia