Updated

This past Thursday, Attorney General Mukasey was delivering an impassioned speech when (as news videos show) he began to hesitate, his words slowed, he shook slightly, his head went down and he crumpled to the ground. He reportedly lost consciousness, but was awake a few moments later. This is known as a syncopal episode, which is a transient blackout usually accompanied by falling, and followed by a prompt recovery.

The most common cause of syncope by far is a faint caused by a slowing of the heart rate and insufficient blood flow to the back of the brain. This is also known as a vasovagal episode and is often brought on by stress or feeling hot, which appears to be what happened to Mukasey. 20-50% of adults experience at least one blackout in their lives, and the percentage increases to 75% over the age of 70. Mukasey is 67.

He was brought to the hospital, and in fact 6 % of all hospital admissions are due to syncope. He was observed and monitored overnight, and tests (including stress test, CT and MRI of the brain) were all negative, confirming that this was likely a faint and not a stroke or heart arrhythmia. TIA or transient ischemic attack, (warning signs of a stroke that lead to an actual stroke 1/3 of the time), seemed more and more unlikely.

I think there are three important lessons in Mukasey's sudden blackout. A man in good health, who exercises regularly, he returned to work the following day_

1) We in the media are sometimes too quick to jump to the worst possible conclusions. As soon as Mukasey blacked out, early news reports were speculating stroke, when in fact the most likely explanation was a faint.

2) Expert medical training is important to distinguish between benign and more concerning symptoms. A good neurologist takes a comprehensive history and conducts a comprehensive exam before ordering tests. A good neurologist could tell that Mukasey's symptoms - despite appearing scary were likely benign.

3) At the same time, it is important that if you do black out, that you seek medical attention right away. A disturbing number of patients ignore a faint and refuse a workup. But a thorough syncopal work-up, such as the one Mukasey had, can sometimes show that a blackout is not due to a simple faint.

Dr. Marc Siegel is an internist and associate professor of medicine at the NYU School of Medicine. He is a FOX News Medical Contributor and writes a health column for LA Times, where he examines TV and movies for medical accuracy. Dr. Siegel is the author of "False Alarm: the Truth About the Epidemic of Fear" and "Bird Flu: Everything You Need to Know About the Next Pandemic". Read more at www.doctorsiegel.com