What to know about kidney infections
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 a kidney infection, as are pregnant mothers, children under 2 years of age, and individuals aged over 60 years.
Kidney infections affect an estimated 3 to 4 men in every 10,000 and 15 to 17 in every 10,000 women.
This article will explain the symptoms of a kidney infection and how it is diagnosed, prevented, and treated.
What Causes a Kidney Infection?
A kidney infection is caused by bacteria entering the urethra and reproducing in the bladder, triggering an infection. The infection then spreads to the kidneys. There are a number of ways in 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 getting through and working its way up to the kidneys. The infection could also enter via the anus. Bacteria occupy the colon and eventually cause a kidney infection.
- Female physiology: Women are more vulnerable to bladder infections and ultimately kidney infections than men, because their urethra is shorter, making it easier for infections to reach parts of the urinary tract more quickly.
- Urinary catheter: A urinary catheter is a tube that is inserted into the bladder through the urethra to drain out urine. Having a urinary catheter raises the risk of developing a urinary tract infection (UTI). This includes 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: Some 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.
Who Gets Them?
Anyone can. But just as women get more bladder infections than men, they also get more kidney infections.
A woman’s urethra is shorter than a man’s, and it’s closer to the vagina and anus, where bacteria live. That means it’s easier for bacteria to get into a woman’s urethra, and once they do, it’s a shorter trip to the bladder. From there, they can spread to the kidneys.
Pregnant women are even more likely to get bladder infections because the baby can put pressure on the woman’s ureters and slow the flow of urine.
What are the symptoms of kidney infections?
Symptoms of a kidney infection usually appear two days after infection. Your symptoms may vary, depending on your age. Common symptoms include:
- pain in your abdomen, back, groin, or side
- nausea or vomiting
- frequent urination or the feeling that you have to urinate
- burning or pain while urinating
- pus or blood in your urine
- bad-smelling or cloudy urine
Children under 2 years old with a kidney infection may have only a high fever. People over 65 may only have problems like mental confusion and jumbled speech.
If the infection is not treated promptly, symptoms could worsen, leading to sepsis. This can be life-threatening. Symptoms of sepsis include:
- rapid breathing and heart rate
Risk factors of Kidney Infection
Anyone can get a kidney infection, but here are some factors that make it more likely:
- Urinary tract infections (UTIs). About 1 out of 30 UTIs lead to a kidney infection.
- Being female. Women are more at risk than men for kidney infections because the urethra is shorter than it is in men. This makes it easier for bacteria to reach the urinary tract. Also, the urethra in women is closer to the vagina and anus, which allows bacteria to spread more easily to the urinary tract.
- Pregnancy. The urinary tract shifts in pregnancy and may make it easier for bacteria to get to the kidneys.
- Weakened immune system. This includes people with diabetes, HIV or AIDS, and those taking drugs that suppress the immune system.
- Damage to the spinal cord or nerve damage to the bladder. This could keep you from noticing the signs of a UTI that might lead to a kidney infection.
- Problems emptying your bladder completely. This is called urinary retention. It can also occur in people with spina bifida or multiple sclerosis.
- Use of a catheter to drain your urine.
- Urine backup. This is when your urine backs up to one or both of your kidneys, instead of the normal one-way outflow. It’s called vesicoureteral reflux, and it occurs most commonly in children.
- Problems with the shape of your urinary tract.
- Examination of the bladder with an instrument called a cystoscope.
What is the urinary tract?
The urinary tract consists of:
- The kidneys: The majority of humans have two kidneys, one on either side of the abdomen. Kidneys clear poisonous substances from the blood.
- The ureters: Urine passes from the kidneys to the bladder through tubes called ureters. Each kidney has one ureter connecting it to the bladder.
- The bladder: This is a hollow organ in the lower abdomen that stores urine.
- The urethra: 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.
Treatment of Kidney Infection
Kidney infection can either be treated at home or in a hospital; this will depend on several factors, including the severity of symptoms and the patient’s general state of health.
Treatment at home consists of taking prescribed oral antibiotics. The patient should start to feel better after a few days.
It is essential that the individual finishes treatment and complies with their doctor’s instructions.
Consuming plenty of fluids will help prevent fever and dehydration. Fluid intake recommendations may vary, depending on the type of infection.
The doctor may also prescribe an analgesic if there is any pain.
If the individual is treated in a hospital and suffers from dehydration, fluids may be administered with a drip. Most cases of hospitalization do not last more than 3-7 days.
Subsequent urine and blood tests will tell the doctor how effective treatment has been.
The following factors are more likely to lead to treatment being administered in hospital for kidney infection:
- serious difficulties urinating
- cancer and chemotherapy or radiotherapy
- sickle cell anemia
- a history of kidney infection
- a blockage in the kidneys
- being pregnant
- severe pain
- severe vomiting
- being aged 60 years or older
Diagnosis of Kidney Infection
A doctor will usually check the patient’s heart rate, blood pressure, temperature, and respiratory rate to check their general state of health. The doctor will also check for signs of dehydration.
A physical exam will be carried out, with particular emphasis on the mid and lower back to see whether there is any sensitivity, pain, or tenderness.
If the patient is a young woman, the doctor may carry out a pelvic exam to verify whether there is any pelvic inflammatory disease (PID). If the female is of childbearing age, a pregnancy test may be recommended.
A urine test can determine the presence of a UTI but not its location. However, a urine test that detects an infection will help the doctor reach a diagnosis.
Complications of Kidney Infection
There are two types of kidney infection:
- Uncomplicated kidney infection: The patient is healthy and serious complications are highly unlikely.
- Complicated kidney infection: The patient is more likely to suffer complications, perhaps because of a pre-existing illness or condition.
If a kidney infection is not treated promptly, there is a risk of serious complications, including:
- Emphysematous pyelonephritis (EPN): This is a very rare, potentially fatal complication. EPN is a severe infection in which kidney tissues are destroyed rapidly. The bacteria that cause the infection to release a toxic gas that accumulates inside the kidney, causing fever, nausea, abdominal pain, vomiting, and confusion.
- Kidney abscesses: pus accumulates in kidney tissues in abscesses. Symptoms include blood in urine, weight loss, and abdominal pain. Sometimes surgery is needed to drain out the pus.
- Blood poisoning, or sepsis: Also a rare but possibly life-threatening complication, sepsis 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).
Prevention of Kidney Infection
Often, a kidney infection is the result of a pre-existing infection in the urinary tract. The best way to prevent a kidney infection from developing is by not having bacteria in the urethra or bladder.
- Hydration: Drink plenty of fluids.
- Urination: Urinate whenever there is an urge. Don’t wait.
- Sexual intercourse: Urinate after sexual intercourse. Wash the genitals before and after intercourse.
- Toilet hygiene: After passing stools, wipe the anus from front to back. This lessens the risk of spreading bacteria to the genitals.
- Fiber: 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.
Frequently Asked Questions about Kidney Infection
How much urine does the average adult pass each day?
An average adult passes about 6 cups of urine daily. This amount varies depending on how much you eat and drink and how active you are. During the night, your body produces about half the volume of urine that is produced during the day.
What is the most common cause of a urinary tract infection (UTI)?
The most common cause of a urinary tract infection (UTI) is the bacterium Escherichia coli (E. coli</i>), which is typically found in the colon.
In women, sexual intercourse can cause these bacteria to be introduced into the urinary tract and lead to a bladder infection (cystitis). Other bacteria including Chlamydia, Mycoplasma, and Gonorrhea, as well as the herpes virus, can cause infections of the urethra (urethritis).
What is a common UTI risk factor in adults?
Risk factors for UTIs in adults include:
- Enlarged prostate in men
- Catheters placed in the urethra and bladder
- Spinal cord injury or another nerve injury around the bladder
- Sexual intercourse, including anal intercourse
- Condom use
- Not drinking enough fluids
- Kidney or urinary stones
What are the signs and symptoms of a UTI in adults?
Urinary tract infections are infections that involve the bladder (most common) or the kidneys. Symptoms of a bladder infection include:
- Pain or burning when urinating
- Frequent urge to urinate
- Sudden urge to urinate
- Blood in the urine
Symptoms of a kidney infection are the same as those for a bladder infection, as well as:
- Back pain
- Nausea or vomiting
How many people in the U.S. visit the doctor each year to be treated for a UTI?
Each year, about 8.1 million people see a doctor about a urinary tract infection.
Women tend to be more prone to UTIs than men, for two reasons: their urethra is shorter, allowing easier access for bacteria to get into the bladder, and a woman’s urethral opening is close to the anus and vagina which are sources of bacteria.
To prevent urinary tract infections, some doctors recommend that people drink which liquid?
Cranberry juice has long been touted as a home remedy of choice to prevent urinary tract infections.
The active ingredient in cranberries, A-type proanthocyanidins (PACs), has been shown to block bacteria from adhering to the wall of the bladder. However, it takes an extremely large concentration of cranberry to accomplish this, a concentration not found in typical juices we drink. Further, any concentration of these PACs is long gone by the time it reaches the bladder. Drinking cranberry juice may help hydrate you, which can help wash bacteria from your body, but water can accomplish the same thing. Drinking cranberry juice won’t hurt, but it probably won’t help either.
On average, what percentage of pregnant women develops UTIs?
About 1.5% of women in the U.S. develop a urinary tract infection during pregnancy.
It is believed hormonal changes combined with the increased weight of a growing uterus blocking urine from passing out of the bladder contributes to a greater incidence of UTIs in pregnancy. UTIs in pregnant women involve the kidneys more often than the bladder.
Which antibiotics are used in the treatment of uncomplicated UTIs?
The treatment of choice for urinary tract infections is antibiotics.
Most courses last three to seven days, though if you have a kidney infection you may need to take antibiotics for up to two weeks. The most commonly used medications for treating UTIs include:
- trimethoprim/sulfamethoxazole (Bactrim, Septra, Cotrim)
- nitrofurantoin (Macrodantin, Furadantin)
- fosfomycin (Monurol)
- ciprofloxacin (Cipro)
- levofloxacin (Levaquin)
- cephalexin (Keflex)
- trimethoprim (Trimpex)
- amoxicillin (Amoxil, Trimox, Wymox)
- ampicillin (Omnipen, Polycillin, Principen, Totacillin)
In some cases, medications to numb the bladder such as phenazopyridine (Pyridium) may be prescribed if the UTI is especially painful.
How can women prevent urinary tract infections?
Women can take steps to prevent urinary tract infections.
- Urinate when you feel you need to
- Always wipe from front to back after using the bathroom to prevent spreading bacteria from the anus or vagina into the urethra
- Do not use douches or feminine hygiene sprays, which can irritate the urethra
- Take showers rather than sitting in baths
- Wear cotton underwear and avoid tight-fitting garments
- Drink more water
- Empty the bladder after sexual activity
- Do not use spermicides
- Use tampons instead of pads during menstrual periods
A pregnant woman who develops a UTI needs prompt treatment. True or False?
True. A pregnant woman who develops a UTI must get prompt treatment to prevent a kidney infection. A kidney infection during pregnancy can cause high blood pressure, early labor, premature delivery, and low birth weight.
What causes UTIs in men?
Urinary stones or an enlarged prostate can obstruct the flow of urine and cause a urinary tract infection in men. Catheters placed in the urethra or bladder can introduce bacteria into the urinary tract and cause a UTI.
Drinking water may provide some relief from UTI pain. True or False?
True. Urinary tract infections can be painful. Some home remedies that may provide pain relief include using a heating pad and drinking plenty of water to help flush the urinary tract and rid it of bacteria.
What percentage of women who have a UTI will have another?
In general, about 20%-30% of women that develop a UTI will develop a second UTI. Urinary tract infections are more common in women than in men; up to 20% of women will experience at least one UTI in their lifetime. About 20% percent of women will have a second UTI, and up to 30 percent of those women will have a third. Of those women who have a third UTI, about 80% of them will have recurrent UTIs.
What is the urinary system?
The main organs of the urinary system include two kidneys, two ureters, the bladder, and the urethra. Excess liquid and waste in the blood pass through the kidneys and form urine. Salts and other substances in the Waste and extra fluids in the body are filtered by the kidneys and passed on through tubes called ureters into the bladder.
The bladder holds urine until it is full, and then signals are sent to your brain that it is time to urinate, and urine passes out of the body through a tube called the urethra.
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