A kidney infection, or pyelonephritis, is a painful condition resulting from bacteria travelling from the bladder to one or both kidneys. This condition is more serious than cystitis, a common condition affecting the bladder that makes urinating painful.
With immediate and effective treatment, a kidney infection will not be life-threatening but will cause illness. If a kidney infection remains untreated, it can worsen, causing permanent kidney damage.
The symptoms of a kidney infection often occur within a few hours. It may cause fever, sickness, shivers, and pain in the side or back.
Kidney infection symptoms tend to develop quickly within a few hours or days. These common symptoms include:
Other symptoms may also occur if you have urethritis (urethral infection) or cystitis. These additional symptoms include:
Children who experience a kidney infection may also have the following additional symptoms.
A kidney infection occurs when bacteria enter and infect the kidneys. The bacteria, known as E. coli, live in the bowel.
The bacteria pass through the urethral opening and move upwards through the urinary tract. It first infects the bladder then the kidneys. The bacteria can enter the urinary tract by spreading from the anus to the urethra. It may occur when you wipe your bottom after using the toilet, and the contaminated toilet paper touches your genitals, and also during sex.
A kidney infection can also occur if fungi or bacteria infect the skin, and this infection spreads through the bloodstream to the kidneys, but this rarely occurs. However, a kidney infection usually affects only people with a weakened immune system.
Children and women are at a higher risk of developing a kidney infection, including other urinary tract infections (UTIs) like cystitis.
The urethra is closer to the anus in women than men, making it easier for bacteria from the anus to enter the urethra. Another reason for the increased risk of a kidney infection in women than men is the shorter female urethra than the male urethra, which runs through the penis, making it easier for bacteria to reach the bladder and enter the kidneys.
Anyone can have a kidney infection, but bladder infections are more common in women than men, so more women get kidney infections.
The urethra in females is shorter than in men and closer to their anus and vagina, meaning easier access for viruses and bacteria into the woman’s urethra. When bacteria enter the urethra, it can travel easily into the bladder and spread to the kidneys.
Pregnant women have a higher risk of bladder infections due to hormonal changes and the baby putting pressure on the mother’s bladder and urethra, which slows urine flow.
Any urinary tract problem that prevents urine from flowing as it should can increase the risk of a kidney infection. These include:
You are likely to get a kidney infection if you have:
You need to consult your doctor about your medical history and symptoms to know if you have a kidney infection. The doctor will likely assess your general health by measuring your blood pressure and taking your temperature.
A urine test can determine the presence of a urinary tract infection (UTI). This test involves taking a small urine sample and checking if it contains bacteria. Your provider will give you a container and tell you how to collect the urine.
You can do this at the GP surgery or home. If you collect your urine sample at home, ensure you label the container, seal it in a plastic bag and store it in your fridge. You should submit it at the surgery within four hours.
A urine test cannot diagnose if your infection is in your kidney or another part of your urinary tract, like your bladder. You will need a positive urine test and certain symptoms like pain in your side or fever for your GP to diagnose a kidney infection.
Your healthcare provider may refer you to a hospital for further testing if:
Children with recurrent UTIs may also need further testing at the hospital. In these cases, scans can check for signs of urinary tract problems. These scans may include:
Kidney infections usually start as urinary tract infections (UTIs), affecting the bladder. There is no specific time for UTI to spread from the bladder to the kidneys. A kidney infection can’t resolve on its own.
Untreated kidney infection can lead to a severe infection, potentially causing sepsis or a chronic, recurrent infection.
You may feel better within 2 – 3 days of taking antibiotics. However, ensure you continue taking your medication and complete your treatment course.
Treatment for mild infections can take 7 – 14 days, with symptoms taking a week or longer to resolve with treatment.
A complicated or severe kidney infection may take longer to treat, depending on the extent of the infection and the complications it causes.
Most cases of kidney infections are treatable and cause no complications, but some people develop further health issues. Complications from a kidney infection rarely occur but are more likely to occur in:
Some complications of kidney infections include:
A kidney abscess rarely occurs. It is a serious complication of a kidney infection where pus accumulates in the kidney tissue. People with diabetes are more at risk of developing a kidney abscess. Kidney abscess symptoms are similar to a kidney infection. They include:
A kidney abscess is a potentially serious issue because bacteria in the abscess can spread to other body parts, such as the lungs or bloodstream, and is potentially fatal.
Small abscesses are treatable with antibiotics administered through a drip. Surgery may be necessary for larger abscesses. The procedure will involve draining the pus from the abscess using a needle inserted into the kidney.
Blood poisoning, also known as sepsis, is another rare complication but potentially life-threatening. It occurs when bacteria spread from the kidneys into the bloodstream. When bacteria enter your blood, the infection can easily spread to any body part, including your major organs.
The symptoms of blood poisoning from a kidney infection may include:
Blood poisoning requires immediate medical attention, involving hospital intensive care (ICU) admission and administering antibiotics to fight the infection.
If you take certain diabetes medications like angiotensin-converting enzyme (ACE) inhibitors or metformin, you may need to stop them temporarily until you recover. These medications can cause kidney damage during a blood poisoning episode.
Severe infection, known as emphysematous pyelonephritis, is also rare but potentially fatal. In EPN, the kidney tissues get destroyed rapidly, and the bacteria that causes the infection release a toxic gas that accumulates in the kidneys.
The exact cause of EPN is still unclear, but most people who experience it have diabetes. Treatment often involves emergency surgery to remove some parts or all of the affected kidney. You can live an active and full life with only one kidney.
In rare cases, the kidney infection may result in severe kidney damage that causes kidney failure. Kidney failure is potentially life-threatening but can be treated with a kidney transplant or dialysis.
A kidney infection may also cause complications such as premature birth, labour, or high blood pressure (hypertension).
Most cases of kidney infections are treatable at home with a course of antibiotics and painkillers. Ensure you visit your GP if you experience persistent tummy, genital or lower back pain, fever or any changes in your urination pattern.
Children with kidney infection or urinary tract infection (UTI) symptoms, including cystitis, need to see a GP.
If you are getting treatment at home, your provider will prescribe a course of antibiotic capsules or tablets that lasts 7 – 14 days.
Most people, excluding pregnant women, take co-amociclave or ciprofloxacin. Other antibiotics are also effective.
The common side effects of ciprofloxacin include diarrhoea and feeling sick. Co-amoxiclav can make contraceptive patches and pills less effective, so another form of contraception may be necessary during this treatment.
Doctors usually prescribe a 14-day course of antibiotics known as cephalexin for pregnant women.
You will likely start feeling better after treatment starts and should feel completely fine after about two weeks. If your symptoms don’t improve after 24 hours of treatment, contact your doctor.
Painkillers like paracetamol can relieve your pain symptoms and a high temperature. However, avoid taking non-steroidal anti-inflammatory (NSAIDs) such as ibuprofen to relieve pain from a kidney infection. These medications increase the risk of kidney problems.
Avoid remaining on the toilet seat for too long when you go to the loo if you have a kidney infection. Ensure you drink lots of fluids to prevent dehydration and flush out the bacteria from your kidney. Drink enough fluid so you can frequently pass pale-coloured urine.
Resting is also important. A kidney infection is usually physically draining, even if you are usually strong and healthy. It may take about two weeks to be healthy enough to resume work.
Your doctor may refer you to a hospital if you have any underlying urinary tract problem that increases your risk for kidney infections.
Men with kidney infections usually need further investigation because the condition rarely occurs in men. Only women who have had two or more kidney infections get a referral to the hospital. Most children with kidney infections undergo treatment in the hospital.
Treatment in the hospital may be necessary if:
If you are admitted to the hospital for a kidney infection, you may likely get a drip to supply fluids to help prevent dehydration. The drip may also contain antibiotics. You will have regular urine and blood tests to monitor your health and the effectiveness of the antibiotics.
Most people respond well to the treatment; if there are no complications, they can leave the hospital within 3 – 7 days. The treatment will switch to capsules or tablets after your drips with antibiotics are stopped.
There are no effective complementary or alternative therapies or methods to cure a kidney infection. However, some ways are available to increase your comfort during antibiotic treatment. This includes placing a heating pad on your back, side or abdomen to ease pain in the affected areas.
Drinking plenty of liquid can help flush out the bacteria that cause the infection from your system, and resting is also important to help you recover.
The best way to prevent kidney infections is to keep your urethra and bladder free from the infection-causing bacteria.
The following self-help tips can help you achieve this.
Drinking lots of fluids, particularly water, will help flush bacteria from your urinary tract and bladder. You can also prevent urinary tract infections (UTIs) by taking cranberry extracts or drinking cranberry juice.
However, avoid taking cranberry extracts or juice if you take warfarin, a medicine for preventing blood clots. Cranberry juice can make warfarin more potent, increasing the risk of excessive bleeding.
The following will help prevent bacteria from entering your urinary tract.
Constipation may increase the risk of a urinary tract infection, so treating it as soon as possible is important. The recommended constipation treatments include:
Visit your doctor if your symptoms do not improve after 14 days, but after seven days for children.
If you keep getting UTI more than three times a year, avoid using diaphragms or spermicide-coated condoms, as spermicide can cause bacteria production.
Opt for lubricated condoms without spermicide because unlubricated condoms may irritate the urethra, increasing the risk of infection.
Visit your doctor if you have persistent genital, tummy or lower back pain and a fever or if you notice changes in your usual urination pattern.
Most kidney infections need immediate treatment with antibiotics to prevent the infection from spreading to the bloodstream or damaging the kidneys. Painkillers may also be necessary to alleviate any pain.
You should feel better after your course of antibiotics, which usually lasts two weeks. In rare cases, the kidney infection may result in further problems, such as kidney abscess or blood poisoning (sepsis).
If you have symptoms of a kidney infection, visit our private GP London to see a general practitioner for your condition.
You can contact us at 020 7499 1991 to book an appointment with our doctor or for more information on kidney infections, including ways to prevent this infection.
What will happen if I do not treat a kidney infection?
Untreated kidney infections can damage the kidneys and cause long-term health issues. In rare cases, kidney infections can cause kidney disease, kidney failure or high blood pressure. If the kidney infection enters the bloodstream, it may result in a serious problem known as sepsis.
Can the kidney infection-causing bacteria become resistant to antibiotics?
Yes, it can. The bacteria can become resistant to only some antibiotics. You will have both blood and urine cultures before starting medications. With these tests, your healthcare provider can know the medicine that will be most effective for you.
How can I prevent kidney infections?
Women should wipe from front to back after using the toilet. This will prevent bacteria from moving into the urethra opening. Urinating after having sex may also help remove bacteria in the urethra. Some contraceptives, excluding spermicidal foam or diaphragms, may help.
What if I am pregnant?
UTIs during pregnancy are dangerous to both the baby and the mother. The infection requires immediate treatment, and safe medicines are available for pregnant women to treat UTIs.