Practice Rational Testing

Investigation of peripheral neuropathy

BMJ 2010; 341 doi: http://dx.doi.org/10.1136/bmj.c6100 (Published 05 November 2010) Cite this as: BMJ 2010;341:c6100
  1. Richard Hughes, visiting professor of neurology
  1. 1National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK
  1. Correspondence to: rhughes11{at}btinternet.com

The investigation of the cause of symmetrical polyneuropathy should be guided by careful history taking and examination

Learning points

  • Diabetes, alcohol misuse, and HIV infection are the most common causes of distal symmetrical sensory neuropathy

  • Also consider vitamin B-12 deficiency, uraemia, paraproteinaemia, and hypothyroidism

  • If the cause and management are obvious, as in diabetes or alcohol misuse, specialist referral may be avoided. Red flags for referral to a neurologist are uncertain cause, severe symptoms, rapid progression, and weakness

  • Chronic idiopathic axonal polyneuropathy is a diagnosis of exclusion, with uncertain prevalence (10-40% of hospital series of chronic axonal polyneuropathy) and possible association with impaired glucose tolerance or metabolic syndrome

A 65 year old woman presented with gradual onset of burning pain and loss of feeling in her toes spreading up to her ankles over three months. She had no family history of similar illness and no known other disease. She drank only the occasional glass of wine, and had not been exposed to any drugs or known toxins. Examination was normal except that she had a body mass index of 32, absent ankle reflexes; absent flexor plantar responses; and reduced pinprick, light touch, and vibration sensation in her toes.

What is the next investigation?

The clinical picture points to a diagnosis of a distal symmetrical polyneuropathy of large myelinated nerve fibres (causing numbness, impaired light touch and vibration sensation, and loss of ankle reflexes) and small myelinated and unmyelinated …

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