Kidney infection: Symptoms, Causes, Diagnosis, Treatment, Complications and Prevention

Updated: June 16, 2022

Kidney infection, also known as renal infection or pyelonephritis, is a common type of urinary tract infection. Bacteria often infect the bladder or the urethra and spreads to one of the kidneys. Women are most commonly affected by kidney infection then men. Pregnant mothers, children under 2 years of age, and individuals aged over 60 years are at higher risk of developing kidney infection.
Diarrhea, nausea, and back pain are the most common symptoms of kidney infections. Sometimes, a bladder infection may occur at the same time as a kidney infection. Oral antibiotics can successfully treat kidney infections in most of the cases.

Symptoms of Kidney infection:

Kidney infection normally develops quite fast, in a day or a few hours. Symptoms of a kidney infection include:

• diarrhea
• nausea
• vomiting
• uncontrollable shivering
• back pain
• pain in the groin
• pain in the side
• often symptoms are worse when the patient urinates

If there is also a corresponding bladder infection, the individual may experience:

• bloody urine
• cloudy urine
• frequent urination
• pain or difficulty while urinating, often described as a burning or stinging sensation
• foul-smelling urine
• inability to urinate fully
• pain in the lower abdomen

Causes of Kidney infection:

When bacteria enters the urethra and reproduces in the bladder, it trigger an infection. The infection then spreads to the kidneys. The urinary tract consists of the kidneys, ureters, bladder and urethra. We have two kidneys, one on either side of the abdomen. The main function of kidney is to filter out the toxic material from our body. Urine passes from the kidneys to the bladder through tubes called ureters. Each kidney has one ureter connecting it to the bladder.
The bladder is a hollow organ in the lower abdomen that stores urine. Urethra is a tube that carries urine from the bladder to outside the body. In males, the urethra travels down the middle of the penis to an opening at the end. In females, the urethra runs from the bladder to just above the vaginal opening. The urethra in females is shorter than in males.
Below explained are the number of ways by which the bacteria can achieve this:

Toilet hygiene:

After going to the toilet and using toilet paper to clean the anus, there may be contact with the genitals, resulting in an infection. The infection then can work its way up to the kidneys. The infection could also enter via the anus. Bacteria then occupy the colon and eventually cause a kidney infection.

Female physiology:

As the urethra of a women is shorter, making it easier for infections to reach parts of the urinary tract more quickly, women are more vulnerable to bladder infections than men which can ultimately lead to kidney infections.

Urinary catheter:

A urinary catheter is a tube that is inserted into the bladder through the urethra to drain out urine. This is used in many medical condition for a patient. Having a urinary catheter raises the risk of developing a urinary tract infection (UTI) resulting in kidney infection.

Kidney stones:

Individuals with kidney stones have a higher risk of developing kidney infection. Kidney stones are the result of a buildup of dissolved minerals on the inner lining of the kidneys.

Enlarged prostate:

Males with an enlarged prostate have a higher risk of developing kidney infections.

Sexually active females:

If sexual intercourse irritates the urethra there may be a higher risk of bacteria getting inside the urinary tract and eventually reaching the kidneys.

Weakened immune systems:

Patients with weakened immune systems may have a bacterial or fungal infection on their skin, which eventually gets into the bloodstream and attacks the kidneys.

Diagnosis of Kidney infection in CKD:

The first step is to check the heart rate, blood pressure, temperature, and respiratory rate to have an idea of general state of health of the patient. Any signs of dehydration will then be checked by the doctor.
A physical examination  will be done, particularly on the mid and lower back to see presence of any sensitivity, pain, or tenderness. A pelvic examination is done to verify whether there is any pelvic inflammatory disease (PID), in case of women patient. A pregnancy test may be recommended if the female is of childbearing age. A urine test can detects an infection that will help the doctor reach a diagnosis. However, can determine the presence of a UTI but not its location.

Treatment of Kidney infection in CKD:

The treatment option will depend on the severity of symptoms and general state of health of the patient. Prescribed oral antibiotics can be taken for treatment at home. The patient should start to feel better after a few days. It is important for the patient to complete the course of antibiotics to avoid further complications. If the course is not completed, it could lead to antibiotic resistance.
Consuming plenty of fluids will help prevent fever and dehydration. However, the recommendation of fluid intake may vary, depending on the type of infection. An analgesic may also prescribed by the doctor if there is any pain.
Fluids may be administered with a drip if the individual is treated in hospital and suffers from dehydration. Subsequent urine and blood tests will ensure the effectiveness of the treatment. The following factors are more likely to lead to treatment being administered in hospital for kidney infection:

• diabetes
• serious difficulties urinating
• sickle cell anemia
• a blockage in the kidneys
• a history of kidney infection
• HIV
• cancer and chemotherapy or radiotherapy
• being pregnant
• severe pain
• severe vomiting
• being aged 60 years or older

Complications of Kidney infection in CKD:

If the patient is healthy and serious complications are highly unlikely. This can be called as uncomplicated kidney infection. But in case of complicated kidney infection, the patient is more likely to suffer complications, because of a pre-existing illness or condition.
Left untreated a kidney infection can lead to serious complications, including:

Emphysematous pyelonephritis (EPN):

EPN is a severe infection in which kidney tissues are destroyed rapidly. The bacteria that cause the infection release a toxic gas that accumulates inside the kidney, causing fever, nausea, abdominal pain, vomiting, and confusion. This is a very rare, potentially fatal complication.

Kidney abscesses:

In this condition pus accumulates in kidney tissues in abscesses. Blood in urine, weight loss, and abdominal pain are the most common symptoms. Sometimes surgery is needed to drain out the pus.

Sepsis:

It leads to bacteria spreading from the kidneys into the bloodstream, resulting in infections in any part of the body, including major organs. It is a medical emergency and patients are usually placed in an intensive care unit (ICU). This is also a rare but possibly life-threatening complication.
As a kidney infection can develop quickly and lead to serious complications, visit your doctor immediately if you experience the below symptoms:

• persistent pain
• a high temperature
• a change in urination patterns
• blood in the urine

Prevention of Kidney infection in CKD:

• Drink plenty of fluids
• Urinate whenever there is an urge. Don't wait or hold the urine.
• Urinate after sexual intercourse. Wash the genitals before and after intercourse.
• After passing stools, wipe the anus from front to back. This lessens the risk of spreading bacteria to the genitals
• Eat plenty of fiber so that stools come out easily and do not irritate or cause skin lesions. Constipation increases the risk of developing a kidney infection.