Abstract

Objective: Sympathetic denervation and hyperaemia are implicated in the pathogenesis of Charcot neuro-arthropathy (CN) but also features of diabetic peripheral neuropathy (DPN). Differences in these physiological parameters were sought by determining C-fibre function (LDI flare) and maximum microvascular hyperaemia (MMH) in 13 subjects with diabetic CN (DCN), 10 diabetic neuropaths (DPN) and 10 healthy controls (HC). Additionally, unaffected limbs of the 9 DCN with unilateral charcot (UCN) were studied to determine whether any observed differences precede CN.

Results: The LDIflare was reduced in DPN (1.41 ± 0.51, cm²±SD) and DCN groups (1.42 ± 0.37) compared to HC (5.24 ± 1.33), p<0.0001. MMH was higher in DCN (432 ± 88 PU±SD) than DPN (262 ± 71), p=0.001, though lower than HC (564 ± 112) p < 0.01.

Conclusion: C-fibre function is equally impaired in neuropathic patients with and without CN, however a higher MMH distinguishes those with CN. Unaffected and affected limbs of those with unilateral CN have the same neuro-vascular abnormalities suggesting these precede rather than result from CN.