4.4 Autonomic Disorders (Kincaid)

Question 0

An otherwise young female comes to your office with a history of a recent viral illness. When she stands she has tachycardia but her blood pressure is maintained. What primary autonomic disorder does she likely have?

Answer 0

POTS

postural orthostatic tachycardia syndrome

Question 1

Describe the secondary autonomic condition “Lambert Eaton Syndrome”

Answer 1

Patients have muscle weakness of limbs as a result of an autoimmune reaction in which antibodies are formed against presynaptic voltage-gated calcium channels. Underlying malignancy is commonly small cell lung cancer.

“Antibodies attach ACh synapse at NMJ”

Question 2

What typically happens to heart rate during 1. inspiration and 2. expiration

Answer 2

1. increased heart rate during inspiration
2. decreased heart rate during expiration

i. i. increased inspiration

Question 3

what is the normal ratio of inspiration:expiration in a healthy patient

Answer 3

Normal I:E is about a change of 10-15 BPM

Question 4

why do you apply ACh to skin by iontoporesis during a QSART (quantative sudomotor axon reflex test)

Answer 4

this activates sweat glands so you can measure sudomotor (sweat) output

Question 5

sympathetic efferents release which neurotransmitter?

Answer 5

ACh

Question 6

what is the normal change in blood pressure when going from supine to standing

Answer 6

systolic blood pressure should drop no more than 20

Question 7

how much does the heart rate normally increase when a patient goes from supine to standing.

Answer 7

normally 10-20 BMP (faster in younger)

**the patient from case 2 only had an increase of 2, so this was a clue that he was having autonomic dysfunction.

Question 8

when checking cardiovascular control have patient lie down form 5-10 minutes then stand for 2-3 minutes. the early response is _________(parasympathetic or sympatheti)

Answer 8

early response is parasympathetic/vagal.
later response is sympathetic

**i don’t really understand this concept and will ask KMW for clarification.

Question 9

what is reflex bradycardia

Answer 9

decrease in heart rate in response to the baroreceptor reflex. (mechanism to prevent abnormal increase in BP.)

increased BP (such as when performing the valsalva maneuvre) causes the baroreceptor reflex as a method of decreasing blood pressure by decreasing cardiac output.