You’re probably not constantly on the lookout for signs of a kidney infection. But getting a urinary tract infection (UTI) can open you up to also getting an infection in one or both kidneys, which means this is an illness that should be on your radar. Yep, it’s an unfortunate truth: A urinary tract infection can lead to a kidney infection, which is medically known as pyelonephritis and can be incredibly serious. So if you’re experiencing symptoms of a UTI and thinking, Eh, I can wait a few more days to get those antibiotics, think again. Here’s what you need to know about the signs of a kidney infection, underlying causes, why it’s so important to get treatment as soon as you can, and more.
What Is a Kidney Infection?
Kidney infections are technically a type of UTI, since kidneys are part of your upper urinary tract, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). These infections are typically caused by bacteria called Escherichia coli (E. coli) that is usually found in the large intestine, but it can wreak havoc when it finds itself in the urinary tract.
Kidney infections are “one of the most common urologic conditions that we see in general urology practice,” Fara Bellows, M.D., a urologist at The Ohio State University Wexner Medical Center, tells SELF. Still, kidney infections are no joke.
“This is a serious organ infection, and people need to take care of it,” urologist David Kaufman, M.D., of New York’s Central Park Urology, tells SELF. “Bladder infections are really uncomfortable, but kidney infections can be deadly.”
Kidney Infection Causes
Kidney infections start out in the bladder as a lower urinary tract infection, says Dr. Bellows. (Hence why UTIs are sometimes called bladder infections.) If the bacteria aren’t eradicated and instead move higher up, you can wind up with a kidney infection.
How do this bacteria get to your bladder in the first place, you ask? Well, usually the bacteria move from the anus (remember, E. coli is common in the GI tract) to the urethra, the small tube that carries urine out of your body—and the entrance to the urinary tract, according to the Mayo Clinic. From there, the bacteria can move into the bladder, then into the kidneys through the ureters, which are the tubes that connect the bladder to the kidneys.
Bacteria can more easily make its move from the anus to the urethra if you do things like wipe back to front instead of front to back. More rarely, you can get a kidney infection if bacteria enters your blood during surgery and gets to your kidneys, the NIDDK says. We’ll discuss more risk factors for kidney infection in a bit.
Signs of a Kidney Infection
So, what does a kidney infection feel like? According to the NIDDK, the most common kidney infections symptoms are:
Frequent and painful urination
Pain in your back, side, or groin
But depending on a person’s age, they may not experience all of these kidney infection symptoms. Children younger than 2 may only experience high fever as a sign of kidney infections, the NIDDK says, and people older than 65 might only present with cognitive issues, like confusion, hallucinations, and disorganized speech.
When to See a Doctor
If you have signs of a kidney infection, you should see a doctor right away. Again, a kidney infection is serious—it can sometimes lead to a dangerous and life-threatening health condition called sepsis, the NIDDK says. (Signs of sepsis include fever, chills, a fast breathing and heart rate, rash, and confusion, according to the U.S. National Library of Medicine.) Even if your infection doesn’t progress to that, a kidney infection can become chronic, i.e. long-lasting, and can cause permanent damage to your kidneys, the NIDDK says. Dr. Kaufman recommends heading to your local urgent care facility or emergency room if you have signs of a kidney infection.
How Is a Kidney Infection Diagnosed?
Your doctor will ask about your symptoms, do a physical exam, and will likely want to run some diagnostic tests. Those include a urinalysis, to check your pee under a microscope for bacteria and white blood cells, which your body makes to fight infection, and a urine culture to help find out what kind of bacteria is causing the infection, the NIDDK says. Your doctor may even take a blood sample to check for bacteria or other organisms in your blood, the Mayo Clinic says.