peripheral neuropathy

aetiology

idiopathic
metabolic
- diabetes mellitus
- amyloidosis
- acute intermittent porphyria (AIP)
- chronic renal failure
- dysproteinaemia
vitamin deficiency
- B12 deficiency (subacute combined degeneration)
  - dietary
  - gastric causes of lack of intrinsic factor production impairing GIT absorption
  - chronic abuse of nitrous oxide nangs
- B complex deficiency - alcoholism, Beri Beri
- pellagra
vitamin excess:
- pyridoxine (B6)
  - it seems that higher vitamin B6 levels (eg >=100mg/day supplements), may lead to the development of a predominantly, if not exclusively, sensory neuropathy of the axonal type however, data is inclonclusive due to small sample sizes. Some advisory bodies are recommending max daily intake of 50mg/day - average dietary intake is 5mg/day ¹⁾ However TGA Australia anecdotal reports of a number of patients developing issues with under 50mg/d ²⁾ It appears the mechanism of pyridoxine induced peripheral neuropathy is necrosis of the dorsal root ganglion and is duration and dose dependent. ³⁾
infection
- diphtheria
- leprosy
- tetanus
- botulism
drugs and chemicals
- isoniazid, nitrofurantoin, vincristine
- heavy metals (lead poisoning, mercury poisoning)
- organic chemicals
miscellaneous
- collagen disorders
- malignancy
- sarcoidosis
- Guillain-Barre (ascending motor weakness prominent)
- hereditary causes

¹⁾

²⁾

³⁾