角膜共焦显微镜对于痛性糖尿病神经病变早期诊断的价值

Early diagnosis of painful diabetic neuropathy by corneal confocal microscopy

目的 通过角膜共焦显微镜观察痛性糖尿病神经病变患者的角膜神经改变,评价其对于痛性糖尿病神经病变的早期诊断价值.方法 来自2011年9月至2012年2月北京大学第三医院内分泌科、神经内科住院糖尿病神经病患者45例,包括痛性糖尿病神经病患者20例,非痛性糖尿病神经病患者25例,以及年龄性别匹配的健康对照组50名.采用角膜共焦显微镜观察记录并量化分析角膜上皮下神经纤维形态,同时进行疼痛视觉模拟评分（VAS）,接触性热痛诱发电位（CHEP）,腓肠神经传导速度等检查.结果 t检验显示与非痛性糖尿病神经病患者相比,痛性糖尿病病变组角膜神经纤维长度（NFL）、神经纤维密度（NFD）、神经分支密度（NBD）均显著减少,神经曲折度（NFT）进一步增加（13 ±4比11 ±3、62±24比47±19、32±13比22 ±8、2.8±0.9比3.2±0.8）,差异有统计学意义（t=40.43、27.27、42.21、194.39,P=0.039、0.011、0.017、0.006）.Pearson相关分析显示VAS评分与NFT,NFD,NBD相关（r=0.782,-0.376、-0.504,均P＜0.001）.结论 角膜共焦显微镜作为一种无创新型敏感的检测手段,对于痛性糖尿病神经病的早期诊断有重要价值.

Objective To explore the early diagnosis of painful diabetic neuropathy by observing the alterations in corneal innervation with corneal confocal microscopy.Methods Fifty aged-matched control subjects,45 diabetic neuropathy including 20 subjects with type 2 diabetes and painful neuropathy （PDN） and 25 subjects with type 2 diabetes and painless neuropathy （PLN） underwent detailed evaluations of their neuropathic symptoms.The examinations of visual analogue scale （VAS）,contact heat evoked potential （CHEP） and corneal confocal microscopy （CCM） were employed to quantify small nerve fiber pathology and their degree of pain.We evaluated the use of a novel in vivo technique CCM in assessing painful neuropathy compared to CHEP.Results The results of CHEP and CCM were significantly different in the diabetic groups compared to controls.T test indicated patients with PDN had significant reductions in corneal nerve fiber length （NFL）,nerve branch density （NBD）,nerve fiber density （NFD） and increased corneal nerve fiber tortuosity （NFT） （13 ±4 vs 11 ±3,62 ±24 vs 47 ± 19,32 ± 13 vs 22 ±8,2.8 ±0.9 vs 3.2 ±0.8; t=40.43,27.27,42.21,194.39,P=0.039,0.011,0.017,0.006）,（t=40.43,27.27,42.21,194.39,P =0.039,0.011,0.017,0.006）.Pearson＇s correlation analysis showed pain severity correlated significantly with cornea nerves damage.VAS correlated significantly with NFL,NBD,NFD and NFT （r =0.782,-0.376,-0.504,all P ＜ 0.001）.Conclusion CCM provides a sensitive and noninvasive modality of detecting small nerve fiber damage in patients with PFN.And these abnormalities may be a sensitive predictor for the presence of pain in diabetic neuropathy patients.