What Is a Kidney Infection?

If you have symptoms of a UTI or bladder infection (also known as cystitis), such as pain with urination, smelly urine, low back pain, or discolored urine, it’s important to seek medical treatment to prevent the infection from spreading to your kidneys.

• Fever and chills
• Pain in the lower back or sides
• Nausea and vomiting
• Abdominal or pelvic pain
• Cloudy or smelly urine
• Dark or bloody urine

The infection is thought to occur from bacteria that travel from your gastrointestinal tract to your skin surface, through your urethra to your bladder, then through the tubes (known as ureters) that connect your bladder and kidneys.

Normally, urine flushes any potentially harmful bacteria out of your ureters before they can cause an infection. But sometimes this process is hindered by:

• Structural abnormalities in your ureters or kidneys
• Kidney stones
• Enlarged prostate (benign prostatic hyperplasia)
• Urine backflow (reflux) from your bladder to your kidneys

Kidney infections that spread from your bloodstream tend to develop after surgery or as a consequence of another infection elsewhere in the body. For example, if an artificial joint or heart valve becomes infected, the kidneys can become secondarily infected.

The following factors can increase your risk of developing a kidney infection:

• Being female: In the female anatomy, the urethral opening (where urine exits the body) is close to the vagina and anus, which makes it easy for bacteria from these orifices to enter the urethra. In the male anatomy, the urethral opening is further away from the anus. Female urethras are also shorter than male urethras, which makes it easier for bacteria to travel to the bladder and cause an infection.

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• Being sexually active: Sexual intercourse can make it easier for bacteria in your genital area or anus to enter your urethra, especially for women. Using condoms with spermicidal coating also increases a woman’s risk of developing a UTI.

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• Being pregnant: When you’re pregnant, your enlarged uterus can press against and squeeze your ureters, reducing the flow of urine from your kidneys to your bladder. This reduced urine flow can make it easier for bacteria in your bladder to migrate to your kidneys.

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• Having impaired urine flow: The flow of urine throughout your urinary tract is an important barrier against infection. This flow can be slowed by a narrowed urethra, enlarged prostate, or kidney stone.

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• Having a weakened immune system: Your immune system can be weakened by health conditions such as diabetes, HIV, and cancer, or by certain drugs.

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• Wearing a catheter: Long-term use of a urinary catheter to drain urine from the bladder, such as during a surgical procedure or hospital stay, raises the risk of developing a UTI.

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• Having nerve damage: If you have a spinal cord injury or nerve damage around your bladder, you may not notice when you develop a bladder infection, which can allow it to progress to your kidneys more easily.

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• Having urine reflux problems: A medical condition called vesicoureteral reflux results in small amounts of urine flowing backward from your bladder into your kidneys, potentially carrying bacteria with it.

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  Vesicoureteral reflux is most likely to be diagnosed during childhood.
• Having trouble emptying your bladder: If your bladder doesn’t empty fully, known as urinary retention, the remaining urine can contribute to developing an infection.

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A kidney infection is usually diagnosed based on an assessment of your symptoms, a physical exam, and urine test results that indicate bacteria in your urinary tract.

Kidney infections are treated with antibiotics, either oral or intravenous (IV), depending on the severity of your infection and its symptoms.

Medication Options for Kidney Infection

Drugs typically taken by mouth for kidney infection include:

• Amoxicillin-clavulanate (Augmentin)
• Cephalexin (Keflex)
• Ciprofloxacin (Cipro)
• Levofloxacin (Levaquin)
• Trimethoprim-sulfamethoxazole (Bactrim, Septra)

If additional therapies are needed, you may be given the following drugs via IV in your doctor’s office:

• Ceftriaxone (Rocephin)
• Ciprofloxacin (Cipro IV)
• Gentamicin (Garamycin)

Complementary and Integrative Therapies

There aren’t any effective complementary or integrative methods or therapies for curing a kidney infection.

• Drink lots of water throughout the day.
• Urinate when you feel the urge to do so; don’t wait.
• After using the toilet, wipe from front to back so you don’t spread bacteria from your anus to your urethra.
• Urinate after having sex.
• Don’t use unnecessary cleansing or deodorizing products in the genital area.
• Steer clear of birth control methods that can raise the risk of a UTI.

If you do develop a UTI, get it treated as soon as possible. See your primary healthcare provider for treatment, or visit an urgent care facility for diagnosis and a prescription for antibiotics.

A kidney infection usually starts out as a UTI that affects the bladder. There’s no rule for how long it takes for a UTI to spread from your bladder to your kidneys.

If it isn’t treated promptly, a kidney infection can lead to a number of potentially serious complications.

• Prior kidney disease
• A history of kidney infections
• A structural abnormality in your urinary tract

• High blood pressure: Your blood pressure can rise to unhealthy levels as your immune system tries to fight your infection.
• Kidney failure: If it’s serious enough, an infection can stop your kidneys from effectively removing waste products from your blood.
• Scarring: If you develop scars in your kidneys from an infection, your kidneys may not be able to function properly, potentially leading to chronic kidney disease.
• Blood infection: One of the main jobs of your kidneys is to filter waste products out of your blood. A kidney infection can spread to your entire bloodstream in this process. A bloodstream infection can, in turn, lead to sepsis, which is a severe inflammatory reaction to bacteria. Sepsis can be life-threatening.
• Renal or perinephric abscess: If the infection in your kidney isn’t treated promptly, the bacteria may create an abscess, or pocket of pus, inside or next to your kidney.
• Pregnancy complications: A kidney infection during pregnancy raises the risk of low birth weight in your baby.

“Treatment for kidney infections has largely stayed the same over the last several years,” says Amin S. Herati, MD, an assistant professor of urology at Johns Hopkins Medicine in Baltimore. “[But] there are some new therapies in the pipeline that are very exciting,” he says.

While many diseases affect different populations in the United States at different rates, there isn’t much information available on the relative risk of kidney infection among different racial and ethnic groups.

• Urinary tract infection: Most UTIs affect the lower urinary tract, which includes the urethra and bladder. Bacteria can migrate from the bladder to the kidneys, causing infection there.
• Benign prostatic hyperplasia: Having an enlarged prostate can reduce the flow of urine, making a person more likely to develop a UTI or kidney infection.
• Sepsis: One of the most serious potential complications of a kidney infection, sepsis is an extreme immune system response to infection, resulting in widespread inflammation and sometimes vital organ failure and death.

• Potentially starting as a urinary tract infection, a kidney infection occurs when bacteria travel up your urinary tract.
• Symptoms of kidney infection include fever, back pain, and nausea. Prompt treatment is required to prevent serious complications, such as kidney damage or sepsis.
• Kidney infections are treated with oral or IV antibiotics, depending on the severity of the infection and its symptoms.
• It’s important to see a doctor if you suspect you have a UTI, in order to catch an infection early and stop it from spreading to your kidneys.