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Now, let's talk about diabetic polyneuropathy.
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Diabetic polyneuropathy is a distal, symmetric
polyneuropathy associated with diabetes.
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And it's one of the more common causes of peripheral
neuropathic pain.
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What's happening with diabetes?
Well, it causes a length-dependent sensorimotor
polyneuropathy.
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Longstanding diabetes results in an increased circulation of
glycosylated proteins.
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Those proteins lodge and gum up areas of small vascular
beds,
and one of those is the vasa nervorum, the vascular bed
surrounding the nerves.
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That long-term damage leads to demyelination of sensory and
motor nerves and it is a distal dying back.
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The longest nerves tend to be affected the most and the
earliest.
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So we see symptoms arising initially in the feet, working
their way up the leg
and ascending in a stocking glove distribution.
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When symptoms begin to be apparent in the knees,
we often see patients describe symptoms now arising in the
hands.
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The large and small fibers are affected by diabetes,
and so, we see large fiber symptoms, problems with vibration
and proprioception
as well as small fiber symptoms, problems with neuropathic
pain, paresthesias, and numbness.
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Neuropathic pain is common in diabetic polyneuropathy.
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It's seen in around 35% of diabetic patients.
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Patients will describe tingling, burning, sharp, shooting
sensation,
lancinating sensations, all descriptions of neuropathic
pain.
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Mechanisms include oxidative damage and stress as a result
of that glycosylated protein
and dysfunction of small vascular beds around the nerve,
as well as microvascular changes in the vascular bed around
the nerve.
01:51
How do we treat neuropathic pain in diabetes?
Well, some of the approved medications include duloxetine
and pregabalin
and can be quite effective in many patients.
02:01
There are also a number of off label, not approved,
but off label medications, tricyclic antidepressants are not
uncommonly used,
gabapentin, venlafaxine, and sometimes, topical agents
when pain is localized to a specific region of the body.