EARLY COMPLICATIONS IN TYPE-1 DIABETES - CENTRAL-NERVOUS-SYSTEM ALTERATIONS PRECEDE KIDNEY ABNORMALITIES

Abnormalities of the central nervous system (CNS), as discerned by neu roelectrophysiological studies, and an impaired, charge-related, diffe rential filtration of protein at kidney level as evaluated by selectiv e protein clearance, have recently been shown in diabetes of short dur ation and without any apparent complication. In order to explore the t ime of appearance and possible correlations, CNS and kidney abnormalit ies have been evaluated in parallel both in shortterm and long-standin g type 1 diabetic subjects. Two groups of patients were studied: Group 1 (no. 15), with no previously known clinical sign of complications a nd less than 5 years from diagnosis; Group 2 (no. 15) with more than 1 0 years of disease and with or without clinical signs of diabetic comp lications. Twenty age and sex comparable normal subjects were included in the study (Group 3). Short-latency multimodal evoked potentials (v isual-VEP, brainstem auditory-BAEP, median and tibial somatosensory m- and t-SEP) and charge and/or size selective protein clearances (album in, anionic immunoglobulins, neutral/cationic immunoglobulins) were ev aluated. In Group 1, 27% of patients showed neurophysiological abnorma lities (P < 0.05 vs. Group 3) while one showed proteinuria. In Group 2 , 60% of patients showed electrophysiological changes (P < 0.0001 vs. Group 3) while 67% showed abnormal charge or size selective proteinuri a (P < 0.0001 vs. controls) with a significant association between the abnormalities of CNS and of charge selective proteinuria (P < 0.05). Thus, CNS abnormalities may be detected even in patients with diabetes of short duration and are later associated with subclinical kidney ab normalities. These findings stress the value of the multimodal evoked potential evaluation as a sensitive and early diagnostic approach to t he study of diabetic complications.