Early involvement of the spinal cord in diabetic peripheral neuropathy.
OBJECTIVE
The pathogenesis of diabetic peripheral neuropathy (DPN) is poorly understood. We have recently reported a significant reduction in spinal cord cross-sectional area at the stage of clinically detectable DPN. In this study, we investigated whether spinal cord atrophy occurs in early (subclinical) DPN.


METHODS
Eighty-one male type 1 diabetic subjects, 24 nondiabetic control subjects, and 8 subjects with hereditary sensory motor neuropathy (HSMN) type 1A underwent detailed clinical and neurophysiological assessments. Diabetic subjects were subsequently divided into three groups based on neuropathy severity (19 with no DPN, 23 with subclinical DPN, and 39 with clinically detectable DPN). All subjects underwent magnetic resonance imaging of the cervical spine and cord area measurements at disc level C2/C3.


RESULTS
Mean corrected spinal cord area index (SCAI) (corrected for age, height, and weight) was 67.5 mm [95% CI 64.1-70.9] in diabetic subjects without DPN. Those with subclinical (62.4 mm [59.5-65.3]) and clinically detectable DPN (57.2 mm [54.9-59.6]) had lower mean SCAIs compared with subjects with no DPN (P = 0.03 and P < 0.001, respectively). No significant difference was found between diabetic subjects without DPN and nondiabetic control subjects (69.2 mm [66.3-72.0], P = 0.47). Mean SCAIs in subjects with HSMN type 1A (71.07 mm [65.3-76.9]) were not significantly different from those for nondiabetic control subjects and diabetic subjects without DPN. Among diabetic subjects, SCAI was significantly related to sural sensory conduction velocities and the Neuropathy Composite and Symptom Scores.


CONCLUSIONS
Spinal cord involvement occurs early in DPN. There is also a significant relation between reduction in SCAI and neurophysiological assessments of DPN.
Selvarajah
Dinesh
D
Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield S10 2JF, U.K.
Wilkinson
Iain D
ID
Emery
Celia J
CJ
Harris
Nigel D
ND
Shaw
Pamela J
PJ
Witte
Daniel R
DR
Griffiths
Paul D
PD
Tesfaye
Solomon
S
D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D006442:Glycated Hemoglobin / Q000032:analysis; D006339:Heart Rate; D009477:Hereditary Sensory and Autonomic Neuropathies / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010523:Peripheral Nervous System Diseases / Q000503:physiopathology*; D010543:Peroneal Nerve / Q000098:blood supply; D012016:Reference Values; D013116:Spinal Cord / Q000503:physiopathology*
D006442:Glycated Hemoglobin