Pyelonephritis is a bacterial infection of one or both of the kidneys. The kidneys are two bean-shaped organs in the lower back. Their main function is to remove waste from the body and to balance the water and electrolyte content of the blood by filtering the salt and water in the blood. The waste and water excreted by the kidneys combine to form urine.
Kidney infection may be caused by:
- A bladder infection that was not treated, or was inadequately treated (most common cause)
- Conditions that slow the flow of urine from the bladder, such as an enlarged prostate or kidney stones
- Examination/manipulation of the bladder and urethra using a cystoscope
- Surgery of the urinary tract
- Use of a catheter to drain urine from the bladder
A risk factor is something that increases your chance of getting a disease or condition. Risk factors for a kidney infection include:
- Sex: female
- Sexual activity
- Birth defect of the urinary tract, including vesicoureteral reflux
- Blockage of the urinary tract, including:
- Enlarged prostate gland
- Kidney stones
- Catheter or stent placed in the urinary tract
- Polycystic kidneys
- Sickle cell anemia
- Previous kidney transplant
- Weakened immune system
- Pain in the abdomen, lower back, side, or groin
- Frequent urination
- Urgent urination that produces only a small amount of urine
- Sensation of a full bladder even after urination
- Burning pain with urination
- Fever and chills
- Nausea and vomiting
- Pus and blood in the urine
- Loss of appetite
Your doctor will ask about your symptoms and medical history, and perform a physical exam. A kidney infection is diagnosed with urine tests. You will provide a urine sample in a sterile container. The doctor may ask you to do a "clean catch." This requires that the genital area be cleansed before the specimen is given. A clean catch reduces the likelihood that the urine will be contaminated by bacteria that normally live on the skin.
Urine is examined for bacteria, white blood cells, blood, and other abnormal elements. A culture with sensitivities checks to see what kind of bacteria are growing and what kinds of antibiotics will kill them.
If the infection does not clear up promptly after treatment, or if you have had several kidney infections, you may have other tests to see if there is an anatomical abnormality of the kidney, ureters, and bladder. These tests may include:
- Kidney Ultrasound
- Abdominal CT scan
- Voiding Cystourethrography
Bacterial infections of the kidney are treated with antibiotics. It is very important to take the medication as directed and to finish it all even if the symptoms have stopped. Untreated or inadequately treated kidney infection can lead to chronic infection, scarring of the kidney, and permanent kidney damage. Your doctor will decide if you are well enough to stay home and take antibiotics by mouth. You may need to be in the hospital where you will receive antibiotics and fluids through an intravenous line.
Since pyelonephritis is frequently a complication of a bladder infection, it can best be prevented by preventing bladder infections.
- Drink plenty of fluids (about 8 to 10, 8-ounce glasses per day). Drinking cranberry juice may help prevent bladder infection.
- Practice good hygiene.
- Urinate when you need to. Don't wait.
- Take showers rather than baths.
- For women:
- Wipe from the front to the back after using the toilet to avoid fecal contamination of the urethra.
- Urinate before and after sexual intercourse. Drinking an extra glass of water after intercourse will help flush bacteria.
- Avoid genital deodorant sprays and douches.