15456 Kidney Infection Pyelonephritis

Overview

A kidney infection is a type of urinary tract infection. It starts when bacteria get into the tube that carries urine from the bladder out of the body and travel up to one or both kidneys. It causes pain, fever, and feeling generally unwell. It is more serious than a bladder infection and needs prompt medical treatment.

Kidney infections are less common than bladder infections, but they do affect many people each year. In the UK, around 1 to 2 in every 1,000 people get one each year.

Anyone can get a kidney infection, but they are more common in women, especially between the ages of 15 and 50. Men, children, and older adults can also get them, sometimes for different reasons.

Symptoms

Common symptoms

• Pain in the side or lower back, often on one side
• High temperature (fever) with chills and shivering
• Needing to pee more often than usual
• Pain or a burning feeling when passing urine
• Cloudy, dark, or smelly urine
• Blood in the urine
• Feeling sick or being sick
• Feeling very tired and generally unwell

Symptoms in children

• Fever
• Vomiting
• Poor feeding or loss of appetite
• Tummy pain
• Wetting the bed after being dry
• Irritability and being generally unwell

Symptoms in older adults

• Confusion or feeling muddled
• A high or low body temperature
• A change in behaviour or mobility
• Loss of appetite
• Urinary symptoms that may be less obvious than in younger people

Causes

Main causes

• Bacteria, usually Escherichia coli (E. coli), that live in the bowel and enter the urinary tract.
• Bacteria travelling up from the bladder into the kidneys.
• Rarely, bacteria reaching the kidneys through the bloodstream.

Risk factors

• Being female, because the urethra is shorter
• A urinary tract blockage, such as a kidney stone or enlarged prostate
• Having a urinary catheter
• A weakened immune system
• A condition called vesicoureteral reflux, where urine flows backwards from the bladder to the kidneys
• Pregnancy
• Not drinking enough fluids

When to see a doctor

See a doctor urgently if:

• If you have a high temperature, back pain, and pain when peeing
• If you are pregnant, have diabetes, or have a weakened immune system and have any symptoms of a kidney infection
• If you are being sick and cannot keep fluids down
• If you see blood in your urine

Book a routine appointment if:

• If you have had symptoms for more than 24 hours
• If you have had several urinary tract infections in the past
• If you are concerned about any symptoms

Diagnosis

A doctor will ask about your symptoms, check your temperature, and press gently on your back to see if your kidneys are tender. They will usually ask for a urine sample to test.

Tests that may be done

• A urine dipstick test – a plastic strip with chemicals that change colour if bacteria or white blood cells are present
• A urine sample sent to a laboratory to identify the exact bacteria (urine culture)
• A blood test to check for signs of infection
• An ultrasound, CT scan, or special X-ray if you have frequent infections or a higher risk of complications

What to expect at your appointment

If the doctor suspects a kidney infection, they may start treatment right away, even before test results are back. If you are very unwell or at higher risk, they may send you to hospital for further tests and treatment.

Treatment

A kidney infection is treated with antibiotics. Depending on how unwell you are, you may be treated at home with tablets, or you may need to go to hospital for antibiotics through a drip. It is very important to finish the whole course of antibiotics, even when you start to feel better.

Self-care at home

• Drink plenty of water and other clear fluids to help flush out the bacteria
• Rest until you feel better
• Take over-the-counter pain relief for pain and fever, following the instructions on the packet or advice from your pharmacist
• Use a hot water bottle or heating pad on your stomach or back for comfort
• Avoid caffeine and alcohol until you have recovered

Medical treatments

Your doctor will prescribe antibiotics. You will usually need to take them for 7 to 14 days. If you are admitted to hospital, you may be given antibiotics and fluids through a drip, as well as medicine to help with nausea or fever. Always take your medicines exactly as prescribed and finish the full course, even if you feel better.

When is surgery considered?

Surgery is rarely needed for a kidney infection. However, if there is a kidney stone blocking urine flow, an abscess (a pocket of pus) in the kidney, or another structural problem, you may need a procedure to drain the pus or remove the blockage.

Living with this condition

Take it easy while your body fights the infection. Rest, drink plenty of fluids, and take your medicines as prescribed. If you are not feeling better within two days, contact your doctor.

Lifestyle tips

• Try not to hold in your pee – go when you first feel the need
• Empty your bladder fully when you go to the toilet
• Drink plenty of fluids throughout the day
• Wear loose, cotton underwear
• Keep yourself clean and dry

Diet and exercise

Eat a balanced diet with plenty of fruit, vegetables, and whole grains. Cranberry juice may help prevent urinary tract infections, but it cannot treat a kidney infection. Stay well hydrated, and avoid intense exercise until you feel better.

Mental health and emotional wellbeing

Being ill with a kidney infection can be exhausting and worrying. It is normal to feel low or anxious while you recover. Give yourself time to heal, and talk to people you trust. If you feel very anxious or low, speak to your healthcare provider.

Prevention

Not all kidney infections can be prevented, but many bladder infections that lead to them can be. Drink plenty of fluids, go to the toilet as soon as you feel the need, and wipe from front to back after using the toilet. Drinking extra water after exercise or sex can also help.

Vaccines

There is currently no vaccine to prevent kidney infections.

Screening programmes

There is no routine screening for kidney infections. If you have had several infections, or if you are pregnant, your doctor may recommend regular urine tests.

Complications

If left untreated

• Permanent kidney damage or scarring
• An infection in the bloodstream (sepsis), which is life-threatening
• A kidney abscess, which is a collection of pus inside the kidney
• In rare cases, kidney failure

Long-term outlook

With prompt and proper treatment, almost everyone with a kidney infection makes a full recovery without any lasting damage. Most people begin to feel better within a few days of starting antibiotics. The outlook is very good if you get medical help early.

Find support

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.