Corneal confocal microscopy detects severe small fiber neuropathy in diabetic patients with Charcot neuroarthropathy

• Published in: Journal of diabetes investigation 2018-09, Vol.9 (5), p.1167-1172
• Main Authors: Khan, Adnan, Petropoulos, Ioannis N, Ponirakis, Georgios, Menzies, Robert A, Chidiac, Omar, Pasquier, Jennifer, Abi Khalil, Charbel, Talal, Talal K, Malik, Rayaz A
• Format: Article
• Language: English
• Subjects: Aged; Charcot neuroarthropathy; Conductance; Confocal microscopy; Cornea; Cornea - pathology; Corneal confocal microscopy; Corneal nerves; Diabetes; Diabetes mellitus; Diabetes mellitus (non-insulin dependent); Diabetic Neuropathies - diagnosis; Diabetic Neuropathies - epidemiology; Diabetic neuropathy; Feet; Female; Humans; Male; Microscopy; Microscopy, Confocal - methods; Microscopy, Confocal - standards; Middle Aged; Original; Perception; Severity of Illness Index; Small Fiber Neuropathy - diagnosis; Small Fiber Neuropathy - epidemiology
• ISSN: 2040-1116; 2040-1124
• DOI: 10.1111/jdi.12806

Aims/Introduction The aim of the present study was to identify the extent of small fiber neuropathy in diabetic patients with Charcot neuroarthropathy (CN). Materials and Methods A total of 20 patients with CN were compared with 20 age‐ and diabetes duration‐matched patients with type 2 diabetes and 20 age‐matched control participants. All patients underwent corneal confocal microscopy with quantification of corneal nerve morphology and assessment for vibration perception threshold, and a subset of patients with CN underwent assessment of sudomotor function and neuropathic pain. Results In patients with CN compared with type 2 diabetes patients and control participants, there was a significant reduction in corneal nerve fiber density (14.94 ± 8.23 vs 23.86 ± 7.71, P = 0.004 vs 34.84 ± 9.13, P < 0.001), corneal nerve branch density (18.61 ± 16.7 vs 41.62 ± 22.67, P = 0.032 vs 76.47 ± 38.44, P < 0.001) and corneal nerve fiber length (8.40 ± 4.83 vs 14.87 ± 4.76, P = 0.001 vs 21.24 ± 6.48, P < 0.001), electrochemical skin conductance on the feet (20.57 ± 13.99 vs 61.50 ± 22.26, P < 0.001 vs 76.23 ± 12.01, P < 0.001) and hands (30.86 ± 18.10 vs 61.13 ± 19.14, P = 0.001 vs 68.31 ± 11.96, P < 0.001), and a significant increase in the vibration perception threshold in the feet (38.46 ± 15.10 vs 14.15 ± 10.25, P < 0.001 vs 7.75 ± 4.01, P < 0.001). Conclusions Patients with diabetes and CN have severe large and particularly small fiber neuropathy. Severe small and large fibre neuropathy and sudomotor dysfunction occur in diabetic patients with Charcot neuroarthropathy. Small, as opposed to large fibre neuropathy, may be important in the presentation and progression of Charcot neuroarthropathy.