nbme q - azaaza

[ArchivalUser]

35 year old woman comes to the physician because of intermittent tingling and numbness of her feet during the past 6 months. She has a 30 year h/o of typer 1 DM. sensation of joint postion is decreased in the toes and ankels, and vibration sense is decreased in the feet. There are decreased ankel jerks bilaterally. pathologic changes of which occur?
a. dorsal columns of the spinal cord.
b. large diameter axons of the distal portions of perpheral nerves
c.motoneruons of the lumbosacral spinal cord
d.spinocerebellar tracts of the spinal cord
e.spinothalamic tract neurons of the dorsal horn.

[ArchivalUser]

aaa

[ArchivalUser]

can we explain the decreased ankel jerks bilaterally by dorsal columns lesions?

[ArchivalUser]

true... decreased jerks - are they sign of LMN damage? might be B

[ArchivalUser]

bb

[ArchivalUser]

wrong ... c ... its motoneurons. those smaller fibers are for motor activity and help in alpha motor neuron and with vibration and touch. large fibers are more pain and temperature and not having to do with motor. ITS C

[ArchivalUser]

i think the answer is B.
because in the given options,the only option which explains both the signs is due to the damage of the large diameter peripheral nerves.
the women has the h/o type 1 DM.so there is every possibility that the peripheral nerves are affected because of the osmotic damage to the nerves.
lesion to motor neurons cant explain the loss of jt position and the loss of vibration sense and likewise lesion in dorsal columns cant explain diminished reflexes,