title: Corneal confocal microscopy: a novel means to detect nerve fibre damage in idiopathic small fibre neuropathy.
abstract: Patients with idiopathic small fibre neuropathy (ISFN) have been shown to have significant intraepidermal nerve fibre loss and an increased prevalence of impaired glucose tolerance (IGT). It has been suggested that the dysglycemia of IGT and additional metabolic risk factors may contribute to small nerve fibre damage in these patients. Twenty-five patients with ISFN and 12 aged-matched control subjects underwent a detailed evaluation of neuropathic symptoms, neurological deficits (Neuropathy deficit score (NDS); Nerve Conduction Studies (NCS); Quantitative Sensory Testing (QST) and Corneal Confocal Microscopy (CCM)) to quantify small nerve fibre pathology. Eight (32%) patients had IGT. Whilst all patients with ISFN had significant neuropathic symptoms, NDS, NCS and QST except for warm thresholds were normal. Corneal sensitivity was reduced and CCM demonstrated a significant reduction in corneal nerve fibre density (NFD) (P<0.0001), nerve branch density (NBD) (P<0.0001), nerve fibre length (NFL) (P<0.0001) and an increase in nerve fibre tortuosity (NFT) (P<0.0001). However these parameters did not differ between ISFN patients with and without IGT, nor did they correlate with BMI, lipids and blood pressure. Corneal confocal microscopy provides a sensitive non-invasive means to detect small nerve fibre damage in patients with ISFN and metabolic abnormalities do not relate to nerve damage.
authors.affiliation: Division of Cardiovascular Medicine, Central Manchester Foundation Trust and University of Manchester, Manchester, M13 9NT, UK.
authors.forename: Mitra
authors.initials: M
authors.lastname: Tavakoli
authors.forename: Andrew
authors.initials: A
authors.lastname: Marshall
authors.forename: Robert
authors.initials: R
authors.lastname: Pitceathly
authors.forename: Hassan
authors.initials: H
authors.lastname: Fadavi
authors.forename: David
authors.initials: D
authors.lastname: Gow
authors.forename: Mark E
authors.initials: ME
authors.lastname: Roberts
authors.forename: Nathan
authors.initials: N
authors.lastname: Efron
authors.forename: Andrew Jm
authors.initials: AJ
authors.lastname: Boulton
authors.forename: Rayaz A
authors.initials: RA
authors.lastname: Malik
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D003315:Cornea / Q000294:innervation* / Q000473:pathology*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D005951:Glucose Tolerance Test / Q000379:methods; D006801:Humans; D006930:Hyperalgesia / Q000503:physiopathology; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods*; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009460:Neurologic Examination / Q000379:methods; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis*; D012684:Sensory Thresholds / Q000502:physiology; D014953:Wrist / Q000294:innervation