A kidney infection is a type of urinary tract infection (UTI). A kidney infection may begin in the tube that carries urine from the body (urethra) or in the bladder. The infection can travel to one or both kidneys. A kidney infection is also called pyelonephritis.

A kidney infection needs prompt medical treatment. If not treated properly, an infection can cause lasting damage to the kidneys. Or the bacteria can spread to the bloodstream and cause a dangerous infection.

Causes: Bacteria that enter the urinary tract through the urethra can multiply and travel to your kidneys. This is the most common cause of kidney infections.Bacteria from an infection in another part of the body also can spread through the bloodstream to the kidneys. In rare cases, an artificial joint or heart valve that becomes infected can cause a kidney infection.Rarely, a kidney infection happens after kidney surgery.

Symptoms

Symptoms of a kidney infection might include:

Fever

Chills

A burning feeling or pain when urinating

Having to urinate often

A strong, lasting urge to urinate

Back, side or groin pain

Nausea and vomiting

Pus or blood in the urine

Urine that smells bad or is cloudy

Belly pain

Risk factors :

Factors that increase the risk of a kidney infection include:

Being female. The urethra is shorter in women than in men. That makes it easier for bacteria to travel from outside the body to the bladder. The urethra being close to the vagina and anus also makes it easier for bacteria to enter the bladder.Once in the bladder, an infection can spread to the kidneys.

Pregnant women are at even higher risk of a kidney infection.Having a urinary tract blockage.

Anything that slows the flow of urine or makes it harder to fully empty the bladder can raise the risk of a kidney infection. This includes a kidney stone, a narrowed urethra or an enlarged prostate gland.

Having a weakened immune system. Medical conditions such as diabetes and HIV can weaken the immune system. Certain medicines also can lower immunity. These include drugs taken after an organ transplant that help prevent rejection.

Having damage to nerves around the bladder. Nerve or spinal cord damage can block the feeling of a bladder infection. That can make it hard to know when an infection travels to a kidney.

Using a urinary catheter. Urinary catheters are tubes used to drain urine from the bladder. Catheters are sometimes used after a surgical procedure or diagnostic test. They’re also used in people who are confined to a bed.Having a condition that causes urine to flow the wrong way.

In vesicoureteral reflux, small amounts of urine flow from the bladder back into the tubes that connect the bladder and kidneys. People with this condition are at higher risk of kidney infections when they’re kids and when they become adults.

Complications

If left untreated, a kidney infection can lead to potentially serious complications, such as:Kidney scarring. This can lead to chronic kidney disease, high blood pressure and kidney failure.Blood poisoning. The kidneys filter waste from blood and return the filtered blood to the rest of the body. A kidney infection can cause bacteria to spread through the bloodstream.Pregnancy complications. A kidney infection that occurs during pregnancy can increase the risk of having a baby with a low birth weight.

Prevention

Reduce your risk of kidney infection by taking steps to prevent urinary tract infections. Women in particular may lower the risk of urinary tract infections if they

Drink fluids, especially water.

Fluids can help remove bacteria from the body when you urinate.

Urinate as soon as you need to. Don’t delay urinating when you feel the urge.Empty the bladder after sexual intercourse. Urinating as soon as possible after sex helps clear bacteria from the urethra. This lowers the risk of infection.

Wipe carefully.

Wipe from front to back after urinating and after a bowel movement. This helps prevent bacteria from spreading to the urethra.

Avoid using products in the genital area. Deodorant sprays in the genital area or douches can be irritating.

Many people with chronic kidney disease (CKD) will not have symptoms because it does not usually cause problems until it reaches an advanced stage.

Early stages of CKD

Kidney disease does not tend to cause symptoms when it’s at an early stage.This is because the body is usually able to cope with a significant reduction in kidney function.

Kidney disease is often only diagnosed at this stage if a routine test for another condition, such as a blood or urine test, detects a possible problem.If it’s found at an early stage, medicine and regular tests to monitor it may help stop it becoming more advanced.

Later stages of CKD number of symptoms can develop if kidney disease is not found early or it gets worse despite treatment.

Symptoms can include:

weight loss and poor appetite

swollen ankles, feet or hands – as a result of water retention (oedema)

shortness of breath tiredness

blood in your pee (urine)an increased need to pee – particularly at night difficultysleeping (insomnia)

itchy skin

muscle cramps feeling sick

headaches

erectile dysfunction in men.

This stage of CKD is known as kidney failure, end-stage renal disease or established renal failure. It may eventually require treatment with dialysis or a kidney transplant.check for blood or protein in your urineAlongside your eGFR, urine tests can help give a more accurate picture of how well your kidneys are working.

Other tests

Sometimes other tests are also used to assess the level of damage to your kidneys.

These may include:an ultrasound scan, MRI scan or CT scan – to see what the kidneys look like and check whether there are any blockages a kidney biopsy – a small sample of kidney tissue is removed using a needle and the cells are examined under a microscope for signs of damage.