Pathophysiology of central nervous system complications in diabetes mellitus.

It is now generally accepted that diabetes can alter central nervous system (CNS) function. Even in the absence of overt cerebrovascular accidents or repeated hypoglycemic reactions, uncontrolled hyperglycemia is associated with cognitive changes. These changes are documented both in patients with diabetes as well as in animal models of experimental diabetes. The cognitive impairment can be ameliorated with optimization of blood glucose control. The potential causes of CNS dysfunction in diabetes can be broadly categorized as either vascular causes including changes in the blood-brain barrier and metabolic changes. The latter causes include repeated hypoglycemic episodes, hyperglycemia, hyperosmolality, acidosis, ketosis, neuroendocrine or neurochemical changes. The other contributory causes of CNS dysfunction in diabetes include the presence of hypertension, uremia, peripheral and autonomic neuropathy and multiple drug use.