DELAYED RECOVERY OF NERVE-CONDUCTION AND VIBRATORY SENSIBILITY AFTER ISCHEMIC BLOCK IN PATIENTS WITH DIABETES-MELLITUS

Objectives - To determine if the recovery of nerve function after isch aemic block is impaired in patients with diabetes mellitus relative to healthy controls. Methods - Median nerve impulse conduction and vibra tory thresholds in the same innervation territory were studied in pati ents with diabetes mellitus (n = 16) and age matched controls (n = 10) during and after 30 minutes of cuffing of the forearm. Results - Cuff ing caused a 50% reduction of the compound nerve action potential (CNA P) after 21.9 (SEM 1.6) minutes in patients with diabetes mellitus and after 10.6 (0.7) minutes in controls. After release of the cuff the h alf Life for CNAP recovery was 5.13 (0.45) minutes in patients with di abetes mellitus and <1 minute in controls. At seven minutes after rele ase of the cuff CNAP was fully restored in the controls whereas in pat ients with diabetes mellitus CNAP had only reached 75.1 (4.1)% of its original amplitude. After onset of ischaemia it took 14.6 (1.9) minute s in patients with diabetes mellitus before the vibratory threshold wa s doubled, whereas this took 5.8 (0.8) minutes in controls. After rele ase of the cuff half time for recovery of vibratory threshold was 8.8 (1.0) minutes in patients with diabetes mellitus and 2.6 (0.3) minutes in controls. Ten minutes after the cuff was released the threshold wa s still raised (2.0 (0.3)-fold) in the diabetes mellitus group, wherea s it was normalised in controls. Among patients with diabetes mellitus the impaired recovery correlated with older age, higher HbA1c, and si gns of neuropathy, but not with blood glucose. Conclusion - After isch aemia there is a delayed recovery of nerve conduction and the vibrator y sensibility in patients with diabetes mellitus. Impaired recovery af ter ischaemic insults may contribute to the high frequency of entrapme nt neuropathy in patients with diabetes mellitus.