An infection of one or both kidneys is called pyelonephritis. It usually happens when bacteria (or in rare cases, viruses, fungi, or other disease-causing organisms) get into the kidneys. The bacteria (or other disease-causing organisms) can enter the kidneys from the bladder. Or they can enter through blood traveling from other parts of the body to cause pyelonephritis. A kidney infection can become serious. It can cause severe illness, scarring of the kidneys, or kidney failure if not treated correctly.
Causes of kidney infection may include:
- Not keeping the genital area clean and dry, which promotes the growth of bacteria.
- Wearing tight pants or underwear, which allows moisture to build up in the genital area, helping bacteria grow.
- Holding urine for long periods of time.
- Fluid loss (dehydration).
- Kidney stones.
- A structural problem in the urinary tract.
- Frequent urinary tract infections.
Kidney infections can cause symptoms similar to bladder infections. The infection can cause one or more of these symptoms:
- Pain or a burning feeling when urinating
- Having to urinate more often than normal
- Blood in urine (pink or red)
- Belly pain or discomfort, often in the lower belly
- Pain in the side or back
- Pain above the pubic bone
- Fever or chills
- Vomiting
- Loss of appetite
For bacterial infections, treatment is oral antibiotics. Or in more severe cases, intramuscular or I.V. (intravenous) antibiotics may be used. These are started right away. Treatment helps prevent a more serious kidney infection.
Medicines
Medicines can help in the treatment of kidney infection:
- Take antibiotics until they are used up, even if you feel better. It's important to finish them to make sure the infection is gone.
- Unless another medicine was given, you can use over-the-counter medicines for pain, fever, or discomfort. If you have chronic liver or kidney disease, talk with your doctor before taking these medicines. Also tell your doctor if you've ever had a stomach ulcer or gastrointestinal bleeding, or if you are taking blood thinners.
Home care
These guidelines can help you care for yourself at home:
- Stay home from work or school. Rest in bed until your fever breaks and you are feeling better, or as advised by your doctor.
- Drink lots of fluid unless you must restrict fluids for other medical reasons. This will force the medicine into your urinary system and help flush the bacteria out of your body. Ask your doctor how much you should drink.
- Don't have sex until you have finished all of your medicine and your symptoms are gone.
- Don't have caffeine, alcohol, or spicy foods. These may irritate the kidneys and bladder.
- Wear loose-fitting clothes and cotton underwear.
Prevention
These self-care steps can help prevent future infections:
- Drink plenty of fluids to prevent dehydration and flush out the bladder. Do this unless you must restrict your fluids for other health reasons, or your doctor told you not to.
- Wash your hands with soap and clean, running water after using the bathroom.
- Clean your penis regularly. If you aren't circumcised, pull back the foreskin when cleaning.
- Urinate more often. Don't try to hold urine in for a long time.
- Don't wear tight-fitting pants or underwear.
- Improve your diet and prevent constipation. Eat more fresh fruit, vegetables, and fiber. Eat less junk and fatty foods. Constipation can increase your chance of getting a urinary tract infection. Talk with your doctor if you have trouble with bowel movements.
- Urinate right after sex to flush out the bladder.
- Don't practice high-risk sexual behaviors.
Follow-up care
Follow up with your doctor, or as advised. You may need more testing to make sure the infection is getting better. Close follow-up and more testing are very important. They can help your doctor find the cause and prevent future infections.
If a urine culture was done, you will be told if your treatment needs to be changed. If directed, you can call to find out the results.
If you had an X-ray, CT scan, or another diagnostic test, you will be told of any new findings that may affect your care.
Call 911
Call
- Have trouble breathing.
- Faint or lose consciousness.
- Have a fast or very slow heart rate.
- Feel weak or dizzy.
- Have trouble waking up or are confused.
When to get medical care
Contact your doctor right away if you:
- Have a fever of 100.4ºF (38ºC) or higher, or as advised by your doctor.
- Are not feeling better within 1 to 2 days after starting antibiotics.
- Have any symptom that continues after 3 days of treatment.
- Have increasing pain in the stomach, back, side, or groin area.
- Have repeated vomiting.
- Are not able to take prescribed medicine due to upset stomach (nausea) or another reason.
- Have bloody, dark-colored, or bad-smelling urine.
- Have trouble urinating or decreased urine output.
- Have no urine for 8 hours, no tears when crying, sunken eyes, or dry mouth.
- Have new symptoms or symptoms get worse.


