Symptoms that are difficult to diagnose; whether additional medical tests are really necessary to make a diagnosis; five things a patient can do to help a doctor make a diagnosis.

Sudden cardiac arrest can happen when there is an electrical problem in the heart. If quick action isn't taken, a person can die in minutes. Fortunately when things suddenly went very wrong for Bob Schmit, his girlfriend was there to save his life.

Post-traumatic stress disorder, or PTSD, is a debilitating mental disorder that can occur after a terrifying event. It was first brought to attention by returning war veterans, many of whom had been wounded in battle. Zachary Bell, former U.S. Marine, shares his story of horror in Afghanistan and his battle to regain his mental health after serving our country.