Fainting, also known as syncope, is an unexpected and temporary loss of consciousness resulting from inadequate blood flow to the brain. Fainting is a symptom of an underlying cause or condition, not a disease in itself. It may be due to a minor, serious or unknown condition.

In people with diabetes, causes of fainting can include hypoglycemia (low glucose levels), severe hyperglycemia, nerve damage or heart conditions. All patients, especially those with diabetes, should inform their physician of any episodes of fainting or near-fainting as soon as possible after the event.

Various diagnostic tests can help determine the cause of fainting. These tests include glucose tests, a tilt table test, an echocardiogram, a Holter monitor, event monitor, cardiac catheterization and an electrophysiologic study. In addition, a CAT scan or an MRI may be used to evaluate possible neurologic causes.

Treatment for fainting depends on the underlying cause. When the cause is hypoglycemia or hyperglycemia, treatment will involve maintaining glucose levels within the recommended range.