Kidney Infection: Symptoms, Causes, Risks, Complications, Diagnosis, Treatment and Prevention

Illustration of normal kidney and inflammation kidney


Do you wonder why your body forms the urine? These are composed of waste products that need to be excreted from the body. The kidneys are two bean-shaped organs that extract waste from the blood, form urine, and balance body fluids.

When the kidneys malfunction due to various conditions, this may lead to kidney failure, a serious condition that means the kidneys have stopped working well enough for you to survive without dialysis or a kidney transplant.

There are two kidneys, each is about the size of a fist and is located on either side of the spine. In each kidney, there are millions of small units called nephron and each nephron contains a filtering unit to cleanse the blood from waste products.

Many diseases can affect the kidneys and their functions, and one of the most common is a kidney infection. Also dubbed as pyelonephritis, kidney infection is a type of urinary tract infection (UTI) and travels up to the kidneys.

If the infection is treated with antibiotics immediately, the kidney infection does not cause any harm. However, if it’s not treated, it could lead to permanent kidney damage.


The symptoms of pyelonephritis often appear within just a few hours. Most patients become shivery, sick, feverish and have pain on the back or side of the trunk (flank pain).

The common signs and symptoms of kidney infection usually develop quickly, and these include:

  • Pain on the back or the side
  • Pain around the genitals
  • High fever
  • Chills or shivering
  • Fatigue
  • Anorexia or loss of appetite
  • Feeling sick
  • Diarrhea
  • Abdominal pain
  • Frequent urination
  • Strong and persistent urge to urinate
  • Burning sensation or pain when urinating
  • Nausea and vomiting
  • Urine that’s cloudy, or foul-smelling
  • Pus or blood in the urine


Bacterial that enter the urinary tract through the tube that carries urine can proliferate and travel to the kidneys. Despite the fact that the urinary system is designed to keep pathogens like bacteria out, they can still infect the urinary tract, particularly Escherichia coli, which is normally found in the intestines.

The bacteria can infect the urinary tract through the urethra and these bacteria can travel into the bladder, and eventually, into the kidneys. You are more likely to develop a kidney infection if you have past bladder infections or has a structural problem in the urinary system.

4Risk Factors

Bacterial infection is the most common cause of pyelonephritis. The risk factors for a kidney infection, include:

Poor toilet hygiene – Some individuals, particularly women, use tissue paper to clean the anus. Do not use the tissue to clean other parts of the genitals because it might cause an infection.

Anatomy of women – Women are more susceptible to bladder infections because their urethra is shorter, making it easier for bacteria to enter the bladder faster.

Urinary catheter – Some patients are connected to a tube or catheter to drain out urine, like those who underwent a surgical operation. Having a catheter increases the risk of having urinary tract infection (UTI) and eventually, kidney infection.

Kidney stones – Some people who have kidney stones are at a heightened risk of developing kidney infection. The stone may irritate the lining of the kidneys, causing infection.

Sexually active females – If the sexual interaction irritates the urethra, there is an increased risk that bacteria will enter the urinary tract and eventually, the kidneys.

Urinary blockage – When there is a disruption in the flow of urine or the ability to empty the bladder, it could lead to a kidney infection because it may irritate the lining of the ureter and bladder, which could also lead to kidney infection.

Weakened immune system – People who are suffering from medical conditions that impair the immune system are at a greater risk of developing kidney infection.
The conditions that can weaken the immune system include human immunodeficiency virus (HIV) infection, acquired immunodeficiency syndrome (AIDS) and diabetes.

Bladder nerve damage – Nerve or spinal cord damage that is connected to the bladder may block the sensations of an infection. This makes the condition progress to a kidney infection.


If the condition is left untreated, it could lead to serious complications, including:

Kidney scarring – The kidneys can have scars that can affect its function. Scarring can lead to chronic kidney disease, kidney failure, and high blood pressure.

Pregnancy complications – Women who have kidney infection during pregnancy may have an increased risk of giving birth to babies with low birth weight.

Blood poisoning or septicemia – The kidneys are responsible for the filtering out of waste products from the blood. If you have a kidney infection, the bacteria can spread to the rest of the body through the bloodstream.

Emphysematous pyelonephritis (EPN) – This is a rare but potentially life-threatening complication. EPN is considered a severe and serious infection wherein the tissues in the kidneys become destroyed. The bacteria causing the infection would release a toxic gas that can build up in the kidney, leading to fever, abdominal pain, confusion, nausea, and vomiting.

Kidney abscesses – Pus builds up in the kidney as a result of the infection. This condition happens when the pus accumulates in the tissues of the kidneys. The common signs and symptoms include weight loss, abdominal pain, and blood in the urine.


The doctor needs to take a complete medical history of the patient and conduct a thorough physical assessment. To diagnose the condition, the doctor will conduct series of tests and will base it on the symptoms reported.

The patient may be asked to provide a urine sample to be sent to the laboratory for testing. The urine will be tested for the presence of bacterial, pus or blood to signal an ongoing infection. The doctor can take a blood sample for culture, too. This is to determine which organism is in the urine. This can also help determine which drug can be used as treatment.

Further tests can also be requested such as an ultrasound, CT scan or an isotope scan.



Antibiotics – Patients with UTI or kidney infections need to have an antibiotic therapy to be treated effectively. If you’re being treated at home, you will be prescribed a course of oral antibiotics between 7 and 14 days.

Usually, ciprofloxacin or co-amoxiclav is recommended, unless pregnant or breastfeeding. Antibiotics are usually the first line of drugs for kidney infections. The symptoms of the infection start to clear up within a few days of treatment. However, it is important to continue with the course until it’s finished.

Pain relievers – For pain, the doctor may prescribe painkillers like paracetamol. This can also address fever. However, other painkillers like NSAIDs such as ibuprofen are not recommended because they may aggravate the kidney problem.

Severe infection treatment – Usually, for severe kidney infections, the patient may be needed to be hospitalized. The treatment in the hospital may require IV fluids, antibiotics, and other treatment options.

Recurrent kidney infections – For people with a misshapen urinary tract, they may suffer from recurrent and frequent kidney infections. In this case, the patient is usually referred to a kidney specialist or urologist for further tests and evaluation. Sometimes, surgical procedures are needed to repair the structural or anatomical abnormality.

Lifestyle management                  

  • Apply warm compress on the abdomen, side and back to ease and relieve pain
  • Stay hydrated by drinking lots of fluids. This will help flush out the bacteria from the urinary tract.
  • Avoid bladder irritants like alcohol or caffeine because these can worsen the feeling or urge to urinate.
  • Eat a wide variety of fruits and vegetables, particularly those rich in vitamin C. Aside from boosting the immune system, vitamin C fastens the repair of tissues that have been inflamed.
  • Take the medicines as directed and as explained. Do not stop taking medicine when your symptoms have improved. Always finish the course of antibiotic therapy to prevent the occurrence of antibiotic resistance, which can cause harder-to-treat infections in the future. Antibiotic-resistant bacteria are very difficult to manage and may cause serious complications.


Kidney infection can be prevented. Here are some things that can help prevent having a kidney infection that could potentially damage the kidneys.

  • Reduce the risk of kidney infection by drinking plenty of water. Fluids, particularly water, can effectively remove the bacteria from the body when you urinate.
  • Urinate as soon as you need to or whenever you have the urge. Do not delay urination and don’t wait.
  • Empty the bladder after sexual intercourse. You should urinate as soon as possible after intercourse to clear the bacteria from the urethra, decreasing the risk of infection. Also, wash the genitals before intercourse.
  • Wipe carefully after urinating. For women, wiping from the front to back after urinating is important. Never wipe from the anus to the urethra. This helps prevent bacteria from entering the urethra.
  • Do not use feminine products to wash the genital area. These products may irritate the genital area and may increase the risk of UTI.
  • Eat plenty of fiber so the stools come out easily and do not irritate the skin.