- How to Prevent
What Is a Kidney Infection?
A kidney infection (pyelonephritis) is a type of urinary tract infection that affects the kidneys. Bacteria and viruses usually first infect the bladder and then move up into the kidneys. Kidney infections may occur in one or both kidneys, are less common than bladder infections, and they occur more frequently in women than men.
What Are the Symptoms of a Kidney Infection?
Symptoms of a kidney infection include:
- Pain in the flank (side of the lower back, where the kidney is located)
- Groin pain
- Burning or pain with urination
- Frequent urination
- Urinary urgency
- Bloody or cloudy urine
- Foul-smelling urine
- Pain above the pubic bone (near the bladder)
- In men, the infection can also involve the prostate, which might cause pain in the pelvis or perineum (the area between the anus and scrotum)
Adults older than 65 years who have a kidney infection may not have the above symptoms but may exhibit problems with thinking, such as:
- Jumbled speech
If you have any symptoms of a kidney infection see a doctor because delaying treatment can lead to serious complications such as sepsis.
What Causes a Kidney Infection?
Kidney infections are caused by bacteria and viruses. Often, these germs enter the body on the genital area and travel into the bladder through the urethra. From there, the germs travel up the ureter(s) into the kidney(s).
Risk factors for developing a kidney infection include:
- Frequent sex or a new sex partner
- A bladder or kidney infection in the past 12 months
- Use of spermicide for birth control or prevention of infection
- A condition that blocks or changes the flow of urine in the kidneys (e.g., kidney stones, ureteral reflux, enlarged prostate, narrowed urethra)
- Being female
- Having a close female relative (mother, sister, or daughter) with a history of urinary tract infections (UTIs)
- Vesicoureteral reflux (VUR), a condition in which urine can back up (reflux) into one or both kidneys
- Spinal cord injury
- Nerve damage around the bladder
- Urinary retention
Kidney Infection Diagnosed?
Kidney infections are usually diagnosed based upon symptoms, a physical examination, and urine testing.
Urine testing for kidney infections includes:
- Urinalysis, which checks for white blood cells in the urine that can be a sign of infection
- Urine culture, which uses a sample of urine to try and grow bacteria in a laboratory to identify the type of bacteria causing the UTI and determine which antibiotics would be effective against that bacteria
If kidney infections recur, additional testing may be recommended to check for abnormalities in the kidneys, ureter, bladder, or urethra, or for kidney stones. Tests may include:
What Is the Treatment for a Kidney Infection?
Kidney infections can lead to serious complications if untreated so it is important to see a doctor and not wait to see if the infection goes away on its own. Treatment for kidney infections depends on the severity of the infection and the patient’s overall health.
Treatment for kidney infections includes:
- If pain is mild and patients can eat and drink, oral antibiotics may be prescribed to take at home
- The choice of antibiotic depends upon the bacteria causing the infection and the severity of the infection
- Over-the-counter (OTC) pain medication
- Hospital treatment
- If a patient has a high fever, severe pain, or cannot keep down food/fluids, intravenous (IV) antibiotics and fluids will be given in a hospital
- Pregnant women with kidney infections are usually hospitalized
What Are Complications of a Kidney Infection?
Complications of kidney infections include:
- Sepsis, a life-threatening response to an infection
- Symptoms of sepsis include fever, chills, rapid breathing and heart rate, rash, and confusion
- A chronic kidney infection can cause permanent damage to the kidneys
How Do You Prevent a Kidney Infection?
People who have recurrent kidney infections and urinary tract infections (UTIs) may be able to prevent them in some cases:
- Increase fluid intake
- Urinate after intercourse
- It is believed this could help flush out germs that can enter the bladder. There is no evidence this prevents bladder infections but it is not harmful.
- Change birth control: avoid spermicides and diaphragms
- Vaginal estrogen may be recommended for women who have been through menopause
- Preventive antibiotics or antibiotics are taken following intercourse, as recommended by your doctor