Neuropathological alterations in diabetic truncal neuropathy: evaluation by skin biopsy
- aInstitute of Neurology, University of Ferrara, Italy, bDepartment of Neurology, cDepartment of Epidemiology, dDepartment of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
- Dr David R Cornblath, Pathology 627, 600 North Wolfe Street, Baltimore, MD 21287–6965, USA. Telephone 001 410 955 2229; fax 001 410 502 6737.
- Received 23 February 1998
- Revised 19 May 1998
- Accepted 1 June 1998
Abstract
OBJECTIVES To describe the neuropathological features in skin biopsies from patients with diabetic truncal neuropathy.
METHODS Three patients with diabetic truncal neuropathy underwent skin biopsies from both symptomatic and asymptomatic regions of the chest and trunk. After local anaesthesia, biopsies were performed using a 3 mm diameter punch device (Acupunch). Intraepidermal nerve fibres (IENFs), the most distal processes of small myelinated and unmyelinated nerve fibres, were identified after staining with PGP 9.5 as previously described.
RESULTS Diabetes was diagnosed at the time of the neurological presentation in two, and one was a known diabetic patient. All three had associated sensory-motor polyneuropathy. In all, skin biopsies showed a marked reduction of both epidermal and dermal nerve fibres in the symptomatic dermatomes, compared with skin from asymptomatic truncal areas. In one patient, a follow up skin biopsy when symptoms had improved showed a return of IENFs.
CONCLUSIONS In diabetic truncal neuropathy, skin biopsies from symptomatic regions show a loss of IENFs. After clinical recovery, there is a return of the IENF population, suggesting that improvement occurs by nerve regeneration. These findings suggest that sensory nerve fibre injury in diabetic truncal neuropathy is distal to or within the sensory ganglia. Skin biopsy provides a possible tool for understanding the pathophysiology of the disease.
