NBME 24 Answers ↦
(40.0 difficulty score)
A 60-year-old woman is receiving cisplatin ...
Agreed - I think I got this by thinking about tabes dorsalis (syphillis) and why it has hyporeflexia is due to dorsal root damage
I'm confused about why it wouldn't cause muscle atrophy. Isn't that a fever of LMN damage?
Muscle atrophy wont occur because alpha motor neuron is intact. Motor control of Corticospinal tract on this is intact. so no atrophy. u can move shiti/
But remeber muscle spindle that is responsible for INITIATING stretach reflex send Ia fibre to DRG from where it synapse with Alpha motor neuron. if DRG is damage ur muscle is fine but u cant initiate strech reflex. areflexia
Imagine a simple reflex arc: you have an afferent neuron, some interneuron shenanigans, and an efferent neuron (aka LMN neuron).
If you damage the LMN, you will get hyporeflexia (due to damaged reflex arc) and fibrillations (because your LMN won't be able to effectively contract muscle on command). However, if you damage the afferent part of the arc, you will still get a damaged reflex arc (hyporeflexia), but your motor neuron will still be able to do its stimulating effectively, so your muscles won't show weak contractions when stimulated by a higher pathway. Kinda confusing but I hope I made it a tad simpler!
Very helpful image, thanks bro