Background: Very few reports focus on the relationship between hypoglicaemia and transient loss of consciousness.
Objectives: The aim of this work is to determine whether diabetic patients with transient loss of consciousness have blood glycaemia lower than that of individuals in the control group, and to identify the clinical elements that characterize the kind of transient loss of consciousness.
Methods: Consecutive patients with diabetes and observed for transient loss of consciousness were studied. The inclusion criteria were as follows: that at the syncope a reliable witness was present and determination of glycaemia at arrival to hospital without pharmacological or food interference. The length of syncope, muscle tone, postcritical mental status and autonomic symptoms were assessed using a dedicated protocol.
Results: The study included 40 patients. They had characteristics that were different from those of the controls: they had lower glycaemia at hospital recovery (4.4 vs. 6.2 mmol/l), longer transient loss of consciousness (19 vs. 6 min), lower occurrence of muscle tone loss (8 vs. 25 patients) and higher occurrence of mental impairment after the episode (26 vs. 13 patients). The associated autonomic symptoms were not significant (20 vs. 27 patients).
Conclusion: There was an association between episodes of transient loss of consciousness and low levels of glycaemia in diabetic patients on treatment. They had specific characteristics: they maintained muscle tone and showed postcritical mental impairment. These findings have diagnostic and therapeutic implications.