A kidney infection, also known as pyelonephritis, is a type of urinary tract infection (UTI) that affects one or both kidneys. It is usually caused by bacteria that have spread from the bladder or urethra to the kidneys.

Symptoms of a kidney infection may include:

1. Pain in the back, side, or groin
2. High fever
3. Chills and shaking
4. Nausea and vomiting
5. Cloudy or bloody urine
6. Frequent and urgent urination
7. Fatigue and weakness

If left untreated, a kidney infection can cause serious complications, such as permanent kidney damage or sepsis, which is a life-threatening condition.

Treatment for a kidney infection typically involves antibiotics to kill the bacteria causing the infection. It is important to complete the full course of antibiotics as prescribed, even if you start feeling better before the medication is finished. Pain relievers may also be recommended to help relieve any discomfort.

In some cases, hospitalization may be necessary for intravenous antibiotics and fluids, especially for severe infections or for individuals with other health complications. Additionally, it is important to stay well-hydrated and to avoid caffeine and alcohol while recovering from a kidney infection.

If you suspect you have a kidney infection, it is important to seek medical attention promptly to prevent complications.

Bacteria that enter your urinary tract through the tube that carries urine from your body (urethra) can multiply and travel to your kidneys. This is the most common cause of kidney infections.

Bacteria from an infection elsewhere in your body also can spread through your bloodstream to your kidneys. Although it's unusual to develop a kidney infection, it can happen — for instance, if you have an artificial joint or heart valve that becomes infected.

Rarely, kidney infection results after kidney surgery.

Reduce your risk of kidney infection by taking steps to prevent urinary tract infections. Women, in particular, may reduce their risk of urinary tract infections if they:

• Drink fluids, especially water. Fluids can help remove bacteria from your body when you urinate.
• Urinate as soon as you need to. Avoid delaying urination when you feel the urge to urinate.
• Empty the bladder after intercourse. Urinating as soon as possible after intercourse helps clear bacteria from the urethra, reducing your risk of infection.
• Wipe carefully. Wiping from front to back after urinating and after a bowel movement helps prevent bacteria from spreading to the urethra.
• Avoid using feminine products in the genital area. Using products such as deodorant sprays in your genital area or douches can be irritating.

Antibiotics for kidney infections

Antibiotics are the first line of treatment for kidney infections. Which drugs you use and for how long depend on your health and the bacteria found in your urine tests.

Usually, the signs and symptoms of a kidney infection begin to clear up within a few days of treatment. But you might need to continue antibiotics for a week or longer. Take the entire course of antibiotics recommended by your doctor even after you feel better.

Your doctor might recommend a repeat urine culture to ensure the infection has cleared. If the infection is still present, you'll need to take another course of antibiotics.

Hospitalization for severe kidney infections

If your kidney infection is severe, your doctor might admit you to the hospital. Treatment might include antibiotics and fluids that you receive through a vein in your arm (intravenously). How long you'll stay in the hospital depends on the severity of your condition.

Treatment for recurrent kidney infections

An underlying medical problem such as a misshapen urinary tract can cause you to get repeated kidney infections. In that case, you might be referred to a kidney specialist (nephrologist) or urinary surgeon (urologist) for an evaluation. You might need surgery to repair a structural abnormality.