Kelly Clarkson waited a week to get her appendix out. Here’s why that’s a bad idea.

The pop star Kelly Clarkson showed no hint of discomfort Wednesday night as she belted out the lyrics to her newest hit song, “Broken and Beautiful,” while hosting the Billboard Music Awards in Las Vegas.

“I know I’m Superwoman, I know I’m strong," Clarkson sand as she swayed on stage.

But shortly after the performance, Clarkson broke down offstage from the belly pain she had reportedly been suffering from all week. She flew back to Los Angeles and had surgery for appendicitis.

#TheShowMustGoOn, she posted in a tweet after her surgery.

While Clarkson “nailed the surgery” and is now “feeling awesome” as she recovers, any holdup in seeking help for severe belly pain could lead to dire outcomes, experts warn.

And, jumping on a plane with any medical concern — especially when there are quality hospitals and doctors available where you are — is never a good idea, said Rick Pescatore, director of clinical research in the department of emergency medicine at Crozer-Keystone Health System.

A delay in diagnosing appendicitis can have severe and significant consequences, said Pescatore. “I have seen it progress so incredibly rapidly and become really life-threatening,” he said.

The appendix is a tube of tissue, normally around 3 or 4 inches long, that extends from the large intestine.

What the tissue is there for is not certain. But leave an inflamed appendix untreated for too long and it can rupture, potentially leading to sepsis and septic shock, which can be fatal. Other problems include having to remove more of the intestine if infection has spread, and developing adhesions, bands of scar-like tissue that can result in bowel obstructions and lead to further surgeries, Pescatore said.

But, catch it early enough and removal is a relatively straightforward and common procedure, he said.

About 8.6 percent of men and 6.7 percent of women in the United States will develop appendicitis at some point, according to the American Family Physician clinical evidence handbook.

“It is one of the first things you think about when someone comes in with belly pain,” Pescatore said.

At age 37, Clarkson was not a typical patient, he said. Appendicitis tends to happen at a younger age and peaks at about age 20. Another peak in appendicitis occurs around age 65, he said.

Gastroenteritis, gallbladder issues, pregnancy, or something else specific to a patient’s medical history may come to mind first in a woman of Clarkson’s age with belly pain, but appendicitis is always on the list, Pescatore said.

While surgery is still the standard of care, there have been studies using antibiotics as a non-operative treatment for acute appendicitis, he said.

“If you have pain that doesn’t make sense to you, you need to see a doctor,” Pescatore said. “We see this again and again, where patients delay presenting for medical care when they know in their heart of hearts they should."

Symptoms of classic appendicitis include (though not all are always present):