Three year old Caydence Carnley was a little under the weather.
"We thought it was just a little cold you know, nothing out of the ordinary, little cough," her parents told Channel 3's Kathryn Daniel.
That was on a Thursday. By Saturday....
"Her cough seemed to get a little more persistent, gave her a cough suppressant."
Things took a major turn on Sunday evening.
"Her chest was going up and down very rapidly like she was gasping for breath."
Her parents rushed her to the emergency room. Caydence's temperature spiked to 104, her lips were blue.
Chris and Tiffany Carnley thought the pre-schooler had the flu -- turns out what had started as a runny nose had morphed into full blown pneumonia.
"The virus spreads into your lungs and you get viral pneumonia or your immune system is not functioning correctly and you get a bacteria that kind of comes in then and takes advantage of the defenses being down, per se."
Caydence was admitted with what Sacred Heart pediatric critical care doctor Jason Foland suspects was bacterial pneumonia, a fast spreading, very dangerous form of infection.
"Breathing so hard her ribs were showing and her stomach was getting sucked in. Getting worse and worse and worse."
"She had a reasonably rapid deterioration. Through the night and into the morning, she was requiring more oxygen."
Chris said Caydence was struggling so hard to breathe, there was worry her little heart would fail. She was whisked to the to the pediatric intensive care unit where she spent two days under an oxygen mask.
Foland said pneumonia is sneaky, but there are some signs to watch for.
"So the temperature goes up and doesn't come down with simple medications like Tylenol or Motrin."
And the symptom that tipped off the Carnleys.
"The child's breathing becomes not just a little bit fast and a little bit noisy, but now actually begins to look labored."
Foland said watch for children who completely lose their appetite, quit drinking fluids and act lethargic.
Caydence slowly improved and within a week was back to normal. Foland said she's not at an increased risk for future bouts of pneumonia, a fact that greatly relieves her parents.
"That was probably the most terrifying experience. That you know, I went through as a father," Chris Carnley said.