DSA 27 Autonomic Dysfunction Flashcards
is there a compensatory increased heart rate in neurogenic orthostatic hypertension?
no, indicating that there is something neurologically wrong
what is an active compensatory mechanism in patients with non-neurogenic orthostatic hypertension?
pulse rate will increase
what are some diseases that can cause orthostatic hypotension?
multiple system atrophy, peripheral nerve dysfunction
what are the two main symptoms of MSA?
Parkisonian-like symptoms and cerebellar dysfunction
what are some symptoms of peripheral nerve dysfunction?
stock and glove sensory loss and peripheral weakness
subacute or chronic reason for orthostatic hypotension due to peripheral nerve dysfunction?
diabetic polyneuropathy
acute reason for orthostatic hypotension due to peripheral nerve dysfunction?
GBS
Riley-Day familial dysautonomia
causes orthostatic hypotension associated with peripheral nerve dysfunction
what are the key physical findings for Horner’s syndrome?
ptosis, anhydrosis, miosis (think PAM is Horny)
CN III lesion
mydriasis (dilation)
what do you expect to see if orthostatic hypotension is being caused by autonomic dysfunction?
the heart rate will not show the usual compensatory increase, i.e. the baroreceptor reflex is “off”
what is amyloidosis?
rare disease that results from accumulation of amyloid (misfolded proteins)
what is acute intermittent porphyria?
rare autosomal dominant metabolic disorder affecting the production of heme
define orthostatic hypotension
drop in systolic BP >20mmHg and/or drop in diastolic BP >10mmHg within 3 minutes of standing from a supine position
what might be a cause of orthostatic hypotension in an older patient if there is NO compensatory increase in heart rate?
orthostatic hypotension associated with brain disorder. prototype is multiple system atrophy/degeneration
what causes ptosis in Horner’s syndrome?
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.
what is autonomic disturbance causing Horner’s syndrome?
sympathetic damage resulting in unopposed parasympathetic discharge. this then causes constriction
where can the lesion be causing Horner’s syndrome?
hypothalamus, superior cervical ganglion, long ciliary nerve
what in a patient’s history would lead you to suspect hypovolemia?
no family history, no sign of autonomic neuropathy, compensatory tachycardia
______(parasympathetic/sympathetic) fibers in CN 3 are located peripherally. significance?
parasympathetic. receive blood supply from anastomotic plexus so relatively immune to ischemia. more vulnerable to compression
______(parasympathetic/sympathetic) fibers in CN 3 are located interiorly. significance?
sympathetic. receive blood supply from small penetrating arterioles. vulnerable to ischemia
