Why is there absence of DTR reflex in Tabes dorsalis?

[drmedstudent]

should it be absence of PERCEPTION of DTR reflex? cuz thats what dorsal column tract does. any why is there Argyll Robertson pupils?

Also, any1 understand y u get hammar toes, hypertrophic cardiomyopathy, pes cavus, dysarthria, nystagmus in Friedreich's ataxia? judging from the lesion in dorsal column, spinocerebellar, larteral corticospinal tracts i understand y u get staggering gait and frequent falls but not the rest? (FA 2010 pg408)

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[docnotsopc]

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[mmmcdowe]

What are reflexes? They are loops of sensory nerves (I alpha) that go to the dorsal horns, synapse with alpha motor neurons, and cause the contraction. Severe tabes dorsalis causes extension through the dorsal horns sufficient enough to whack these neurons.

 

[Zuhal]

Old school bump (to show I know how to search haha)

Why is there an absence of DTR in Tabes Dorsalis causes degeneration of Dorsal column (ie proprioception, touch )

Any ideas? Thanks

there's also a problem with their proprioceptive sensation which predisposes them to recurrent trauma.
Frederich's ataxia is a spinocerebellar tract problem, hence the ataxia etc. some books say that they might have a problem with vitamin E absorption/functioning.