Hyperglycaemia and neurological injury

Purpose of review Clinical and experimental data suggest that hypergylcaemia lowers the ischaemic neuronal threshold and worsens outcome in the presence of neurological injury from stroke and subarachnoid haemorrhage. This review aims to appraise the trauma, evidence for tight glycaemic control in patients with neurological injury. Recent findings Hyperglycaemia can adversely affect outcome in critically ill patients. Intensive insulin therapy with tight glycaemic control has been advocated for improving outcome in these patients. However, the extent to which intensive insulin therapy and tight control of blood glucose improve outcome after ischaemic neurological insults remains unclear. The benefit of such treatment regimes may be negated by the increased frequency of hypoglycaemic episodes, which may aggravate neurological injury. Although it seems sensible to control hyperglycaemia in patients with neurological injury, the treatment must account for potential hypoglycaemic episodes. Summary Clinical and experimental data suggest that hyperglycaemia lowers the ischaemic neuronal threshold in the presence of neurological injury. Tight glycaemic control may result in hypoglycaemia, which in itself can be detrimental. Therefore, it seems sensible that we should accept slightly less tight blood glucose control than in the critically ill patient without neurological injury.