Polyneuropathy, axonal and demyelinating neuropathies (mechanism of disease)

This is a flowchart on polyneuropathy, covering axonal neuropathy and demyelinating neuropathy, including the etiology, pathophysiology, and manifestations of these conditions.

ADDITIONAL TAGS:
Hypothyroidism
Variable progression, with
periods of recovery, stabilization, exacerbations, slow decline, etc.
Progression: slow decline over years, affecting longer axons (lower extremities) first.
Distal muscle wasting: feet, lower legs, hands (if severe)
Damage to multiple peripheral nerve fibers, mainly involving:
Axon loss → ↓ signal
amplitude (axonal neuropathy)
Risk factors / SDOH
Cell / tissue damage
Nutrition / diet
Polyneuropathy
Medicine / iatrogenic
Infectious / microbial
Biochem / metabolic
Immunology / inflammation
Signs / symptoms
Tests / imaging / labs
Environmental / toxin
Genetic / hereditary
Flow physiology
Pathophysiology
Etiology
Manifestations
Alcohol use disorder
Impaired interaction between Schwann cells and axons →
↓ conduction velocity, ↑ latency (demyelinating neuropathy)
Generalized muscle weakness: distal proximal
Distal sensory loss (abnormal vibration and proprioception pain or temperature)
Diffusely ↓ or absent reflexes
Distal sensory loss (all senses: pain, temperature, proprioception, vibration)
↓ or absent distal reflexes (usually begins in the ankles)
Atrophy of muscles
+/- neuropathic pain, paresthesias, and motor weakness
Burning-foot syndrome: burning pain, tingling, pins-and-needles sensation, or formication (feels like insects crawling on/under skin)
Sensory ataxia
Malnutrition (↓ thiamine)
Cytotoxic effects
Alcoholic polyneuropathy
Diabetes mellitus
Chronic hyperglycemia
Glycation of axon proteins
HIV
Leprosy
Borreliosis
Chemotherapy-induced peripheral neuropathy (cisplatin, doxorubicin)
Drug-induced (suramin, amiodarone)
Diphtheria → diphtheria toxin
Charcot-Marie-Tooth disease (aka Hereditary motor sensory neuropathy)
Scoliosis
Foot deformities (high arches, hammer toes)
Krabbe disease, adrenoleukodystrophy, metachromatic leukodystrophy
Other inflammatory: vasculitis; connective tissue disorders
Other viruses: CMV, VZV, herpes zoster, measles, mumps, rubella, flu
Uremic polyneuropathy
Heavy metals (lead, arsenic, thallium)
Guillain-Barré: cross reactive Ab (molecular mimicry against Schwann cells)
GI or resp infxn
Motor sensory in early dz

[abdullahalshighri]

just wow this channel is a true gem, I was so lost with what polyneuropathy actually entailed but with the mechanism of disease flowchart you made it understandable. I have a neurology oral exam in a week so this is just what i need thanks a lot.

[DrJ]

Thank you for taking time to make this awesome flowchart! Very helpful😊❤

[MsAMAZINGMOM]

Thanks, a nice quick comprehensive breakdown of polyneuropathy. I "might" have Axonal neuropathy, as CIDP has apparantly been ruled out, so now testing for Axonal. Runner's dystonia was also a possible diagnosis but none of the treatments helped, just horrible side-effects.

[db]

Great summary, thanks. But from what I've read leprosy causes both axonal and demyelinating neuropathy since it also infects Schwann cells, .

[kc]

Thanks for the informative flow chart.

[noellerilleau]

I didn't realize that hypothyroidism and borrelia ( both of which I've had ) caused axonal disease. And I have a pretty good idea that none of my doctors over the years knew that either.

[UncleArthur-ifkw]

Interesting video. I have axonal really bad, but it's unknown as to the cause. I don't drink, never did drugs & to my knowledge, don't have the diseases listed in this video. I am in bad shape, though. Severe pain along with numbness at the same time in my legs down to my feet & muscle wasting throughout my body. I'm even getting trouble breathing now at times & it's difficult even taking a shower. I am taking gabpentin & I take 325 to 650mg Tylenol each day.

[noellerilleau]

And I wonder if chickenpox could cause it too ( got that at age 35 )

[dappersapper]

You missed CIDP/AIDP. It’s a demyelinating neuropathy.