Learn about Kidney infection symptoms from Consumer Reports Health.

Kidney infection

What are the symptoms of a kidney infection?

Most people with kidney infections look and feel very sick. The symptoms usually come on suddenly over a few hours or a day.

The main symptoms are:

Source:
Ramakrishnan K, Scheid DC.
Diagnosis and management of acute pyelonephritis in adults.
American Family Physician. 2005; 71: 933-942.

Source:
Czaja CA, Hooton TM.
Update on acute uncomplicated urinary tract infection in women.
Postgraduate Medicine. 2006; 119: 39-45.

A fever
Chills and shivering
Pain and tenderness in your side, or in both sides
Feeling nauseated
Diarrhea
Back pain.

Your kidneys help to make urine and pass it out of your body. So a kidney infection may mean you often need to urinate. You may also get pain when you urinate or generally have pain in your pelvis.

Your urine may also look cloudy or be a different color. It may smell bad or just smell stronger than usual.

Source:
U.S. National Library of Medicine.
Medline Plus medical encylopedia: kidney infection (pyelonephritis).
July 2006. Available at http://www.nlm.nih.gov/medlineplus/ency/article/000522.htm (accessed on 20 October 2008).

Older people with kidney infections sometimes have different symptoms. These could be:

Source:
O'Donnell JA, Hofmann MT.
Urinary tract infections: how to manage nursing home patients with or without chronic catheterization.
Geriatrics. 2002; 57:45-56.

⁴

A fever without other symptoms
Pain in their side or back, along with a fever
Confusion and sluggishness
Loss of appetite.

Up to a third of older people with a kidney infection don't get a fever. About 2 in 10 have symptoms that mainly affect their intestines or their lungs.

Source:
Ramakrishnan K, Scheid DC.
Diagnosis and management of acute pyelonephritis in adults.
American Family Physician. 2005; 71: 933-942.

Some people with a kidney infection get very few symptoms or even none at all. This is known as a silent kidney infection.

Source:
Ramakrishnan K, Scheid DC.
Diagnosis and management of acute pyelonephritis in adults.
American Family Physician. 2005; 71: 933-942.

Infections in other parts of your body that deal with urine, such as your bladder or urethra, can also cause pain when you urinate or make you need to urinate more often. These parts of your body are called your lower urinary tract. It's possible to get a kidney infection and just have the symptoms of an infection in your lower urinary tract.

Some researchers think that up to 3 in 10 people who seem to have an infection in the lower part of their urinary tract actually have a silent kidney infection.

Source:
Ramakrishnan K, Scheid DC.
Diagnosis and management of acute pyelonephritis in adults.
American Family Physician. 2005; 71: 933-942.

Source:
Komaroff AL.
Acute dysuria in women.
New England Journal of Medicine. 1984; 310: 368-375.

⁵

Source:
Bergeron MG.
Treatment of pyelonephritis in adults.
Medical Clinics of North America. 1995; 79: 619-649.

⁶

You are more likely to have a silent kidney infection if you:

Source:
Ramakrishnan K, Scheid DC.
Diagnosis and management of acute pyelonephritis in adults.
American Family Physician. 2005; 71: 933-942.

Have

diabetes
Diabetes is a condition that causes too much sugar to circulate in your blood. It happens when your body stops making a hormone called insulin (type 1 diabetes) or when insulin stops working (type 2 diabetes).

diabetes
Are taking drugs that weaken your

immune system
The immune system is made up of the parts of the body that are devoted to fighting infection. The body is constantly being threatened by infections from things like bacteria, viruses and parasites. The immune system fights these infections in different ways. At the microscopic level, the immune system uses antibodies and white blood cells, which travel in the blood and target infectious agents, such as bacteria. These microscopic parts of the immune system either kill the infectious agent directly, or take it to other parts of the body, like the spleen, where it can be dealt with. The lymph nodes are another important part of the immune system. Within them, white blood cells filter through the foreign material that has entered the blood, to see if there are any infections. When you have a swollen gland during a cold, this is actually a lymph node that is reacting to the infection. Unfortunately, it is possible for the immune system to become confused and to use its destructive powers to target healthy parts of the body. Diseases that result from this type of situation are called autoimmune diseases.

immune system
Have had a kidney transplant
Are pregnant
Had urinary tract infections before you were 12
Have had three or more urinary tract infections in the last year.

The symptoms of a kidney infection can be similar to those of other illnesses. For example, pelvic inflammatory disease, an

inflammation
If your skin or some other part of your body becomes red, swollen, hot or sore, we say it is inflamed. It means that your body is trying to protect you from germs, from something in your body tissues that can hurt you (like a thorn or sliver), or from things that cause allergies (allergens). Inflammation is part of the way the body heals an infection or injury.

inflamed gall bladder, appendicitis and kidney stones can all cause similar symptoms.

Source:
Ramakrishnan K, Scheid DC.
Diagnosis and management of acute pyelonephritis in adults.
American Family Physician. 2005; 71: 933-942.

¹ To check if you really have a kidney infection, your doctor may ask you for a urine sample. Your urine can then be tested for signs of infection.

You will be asked to wash your genital area and collect a sample of urine halfway through urinating.

Source:
National Institute of Diabetic and Digestive and Kidney Diseases.
Urinary tract infection in adults.
December 2005. Available at http://kidney.niddk.nih.gov/kudiseases/pubs/utiadult (accessed on 20 October 2008).

⁷ This way of collecting urine helps stop

bacteria
Bacteria are tiny organisms. There are lots of different types. Some are harmful and can cause disease. But some bacteria live in your body without causing any harm.

bacteria from the skin around your genital area from getting into the sample and confusing the test results.

There are two parts to the urine test:

First, your urine is checked with a dipstick to look for pus.

Source:
Ramakrishnan K, Scheid DC.
Diagnosis and management of acute pyelonephritis in adults.
American Family Physician. 2005; 71: 933-942.

¹ Pus is a thick white or yellowish fluid that can form where you have an infection. It's made up of dead body tissue, bacteria and

white blood cells
White blood cells are the cells in your blood that help your body fight infections. The other cells in your blood, red blood cells, carry oxygen around your body.

white blood cells.
Next, any bacteria found in your urine are grown in a laboratory and tested to see which drug works best against them.

Source:
Ramakrishnan K, Scheid DC.
Diagnosis and management of acute pyelonephritis in adults.
American Family Physician. 2005; 71: 933-942.

¹

Source:
Horcajada JP, Smithson A.
Acute pyelonephritis in adults: an update.
Reviews in Medical Microbiology. 2003; 14: 119-127.

⁸

These may be the only tests that you need. If you have to be treated in the hospital, you'll probably also have a blood test to check whether the infection has spread to your bloodstream.

Source:
Ramakrishnan K, Scheid DC.
Diagnosis and management of acute pyelonephritis in adults.
American Family Physician. 2005; 71: 933-942.

Some people need further tests, such as an

X-ray
X-rays are pictures taken of the inside of your body. They are done by passing very small amounts of radiation through your body and onto film. X-rays can also be used as a treatment, such as in radiation therapy for cancer.

X-ray,

ultrasound
Ultrasound is a tool doctors use to create images of the inside of your body. The ultrasound machine sends out high-frequency sound waves, which are directed at an area of your body through a device such as a probe. The waves reflect off parts of your body to create a picture. Ultrasound is often used to see a developing baby inside a woman's womb.

ultrasound or

CT scan
A CT scan is a type of X-ray. It takes several detailed pictures of the inside of your body from different angles. CT stands for computed tomography. It's also called a CAT scan (computed axial tomography).

CT scan. Your doctor might want to check if you have a blockage or another problem with your bladder or the tubes that carry urine. You may need more tests if:

Source:
Horcajada JP, Smithson A.
Acute pyelonephritis in adults: an update.
Reviews in Medical Microbiology. 2003; 14: 119-127.

⁸

Your doctor isn't sure that you have a kidney infection
You're very sick or have a weakened immune system
You don't get better with

antibiotics
These medications are used to help your immune system fight infection. There are a number of different types of antibiotics that work in different ways to get rid of bacteria, parasites and other infectious agents. Antibiotics do not work against viruses.

antibiotics
Your doctor thinks the infection has led to another health problem (a complication, such as scarring or pus in your kidneys).

Sources for the information on this page:

Ramakrishnan K, Scheid DC.Diagnosis and management of acute pyelonephritis in adults.American Family Physician. 2005; 71: 933-942.

Czaja CA, Hooton TM.Update on acute uncomplicated urinary tract infection in women.Postgraduate Medicine. 2006; 119: 39-45.

U.S. National Library of Medicine.Medline Plus medical encylopedia: kidney infection (pyelonephritis).July 2006. Available at http://www.nlm.nih.gov/medlineplus/ency/article/000522.htm (accessed on 20 October 2008).

O'Donnell JA, Hofmann MT.Urinary tract infections: how to manage nursing home patients with or without chronic catheterization.Geriatrics. 2002; 57:45-56.

Komaroff AL.Acute dysuria in women.New England Journal of Medicine. 1984; 310: 368-375.

Bergeron MG.Treatment of pyelonephritis in adults.Medical Clinics of North America. 1995; 79: 619-649.

National Institute of Diabetic and Digestive and Kidney Diseases.Urinary tract infection in adults.December 2005. Available at http://kidney.niddk.nih.gov/kudiseases/pubs/utiadult (accessed on 20 October 2008).

Horcajada JP, Smithson A.Acute pyelonephritis in adults: an update.Reviews in Medical Microbiology. 2003; 14: 119-127.

This information was last updated on Jan 08, 2009

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