After Hollywood icon Diane Keaton died from bacterial pneumonia, doctors are raising awareness about the symptoms of the infection and how it can turn fatal in a matter of days. "Working as a pulmonologist, I've treated lots of patients with pneumonia," Dr. Emma Lin, a board-certified pulmonologist and sleep medicine specialist who did not treat Keaton, exclusively told Us Weekly. "What I've realized is that awareness and timing for action can save lives. People often overlook signs such as cough or tiredness, assuming it's the simple 'cold.