A kidney infection is an acute disease that usually results from bacteria entering the urethra and migrating to one or both kidneys. Doctors refer to the condition as pyelonephritis, and the severity of an infection can range from mild and barely noticeable to potentially life-threatening. A person who experiences burning sensations while urinating and frequent, sharp lower back pains should visit his or her doctor immediately to be screened for a kidney infection. When the problem is discovered early, it can usually be cured with a course of antibiotics.
A person can acquire a urinary tract infection in many ways. Poor hygiene can result in fecal bacteria entering the urethra, especially in women. Sexually transmitted diseases, unsterilized gynecological tools, acute injuries to the genitals, and autoimmune disorders can also lead to urethral and kidney infections. Rarely, a kidney stone or other blockage in the urinary tract can irritate the lining of a kidney, increasing the risk of a bacterial infection.
Symptoms of a kidney infection can vary, based on the progression of the disease and the type of bacteria involved. Most cases result in urinary problems, such as burning sensations and frequent urges. Occasionally, blood can be present in the urine. A person may also experience fever, nausea, and vomiting as an infection worsens. Some individuals suffer from sharp pains in their abdomens, groins, or lower backs. Without treatment, a kidney infection can cause permanent scarring of organ tissue that can eventually result in kidney failure.
A primary care physician can usually diagnose a kidney infection by evaluating a patient's symptoms and collecting blood and urine samples for laboratory analysis. If the doctor is unsure of the underlying cause, he or she may refer the patient to a nephrologist for further diagnostic testing. A specialist can review laboratory findings to identify particular bacteria and take an x-ray to check for tissue damage. After making a diagnosis, the doctor can determine the best treatment option.
Urine, similar to other fluids in the body, is normally sterile without significant bacterial infection. Therefore, the presence of bacteria in the urine is considered abnormal and may lead to urinary tract infection. Typically, bacteria gain access to the urinary system from outside through the urethra (the drainage tube for urine from the bladder). The bacteria may then ascend in the urinary system and cause kidney infections. Kidney infection (upper UTI) is typically more severe than lower UTI because bacteria may infect the blood stream (bacteremia) from the kidneys.
Bacteria may travel from the rectum or the vagina towards the urethra to gain entry into the urinary system. Other bacteria may enter from the skin. Women are more susceptible to urinary tract infections due to the shorter length of urethra.
There are many factors that may increase the chances for infection of kidney and urinary tract.
Sexual intercourse (in women) may increase the risk of urinary tract infection because of possible introduction of the bacteria around the urethra into the urinary system.
Pregnancy may also increase the incidence of UTI and kidney infection in women, in fact, 2% to 8% of pregnant women may have urinary infections during their pregnancy. This may occur because of slower transit of urine in the ureters during pregnancy from the pressure applied by the uterus.
Urinary catheters (Foley catheters) also increase the risk of developing urinary and kidney infections. These catheters are used in settings where an individual may not be able to urinate due to paralysis, severe illness, bed bound state, incontinence of urine (inability to hold their urine), or bladder dysfunction. Urinary catheters simply provide a physical vehicle for the bacteria from outside to be directly transported into the bladder and the urinary system.
Kidney stones and other structural abnormalities of the urinary system may also cause kidney infection. Impaired draining and blockage of urine may cause bacteria to ascend to the kidney without being washed back down with the urine. Any obstruction to the flow of urine can serve as a focus of infection that can spread to other parts of the urinary tract.
In children, risk factors for kidney infection include female gender, uncircumcised male, structural abnormalities of the urinary tract, and Caucasian race (four times higher than African American).
Some of the common symptoms of kidney infection include:
fever,
nausea,
vomiting,
abdominal pain,
shivering,
shaking - chills,
painful urination (dysuria),
flank and low and mid-back pain (dull kidney pain), and
general malaise.
Signs of kidney infection on exam may include:
fever,
tenderness on the flanks (costo-vertebral angle tenderness, referring to tenderness upon tapping gently on the mid back on the sides), and
clinical evidence of infection in the urinalysis (analysis of urine).
In elderly patients and those with weak immune systems, kidney infection may be more severe with confusion, rapid heart rate, low blood pressure, and dehydration.
Once you've been diagnosed with a kidney infection, your GP will discuss your treatment with you.
Most people can be treated at home by taking a course of antibiotics and possibly painkillers too.
If you're being treated at home, you will be prescribed a seven-day course of antibiotic tablets or capsules.
For most people, apart from pregnant women, antibiotics called ciprofloxacin or Co-amoxiclav are usually recommended.
A 14-day course of an antibiotic called cefalexin is recommended for pregnant women.
Contact your GP for advice if your symptoms fail to improve within 24 hours after starting to take antibiotics.
Taking a painkiller, such as paracetamol, should help to relieve symptoms of pain and a high temperature.
It's also important to drink plenty of fluids because this will help prevent you becoming dehydrated, and it will help to flush out the bacteria from your kidneys. Aim to drink enough so that you're frequently passing pale coloured urine.
If you have a kidney infection, try not to ‘hover’ over the toilet seat when you go to the loo, because it can result in your bladder not being fully emptied.
Make sure that you get plenty of rest. A kidney infection can be physically draining, even if you're normally healthy and strong. It may take up to two weeks before you're fit enough to return to work.
In some instances, you'll need to be treated in hospital rather than at home. Hospital treatment may be needed if:
you're severely dehydrated
you're unable to swallow or keep down any fluids or medications
you have additional symptoms that suggest you may have blood poisoning, such as a rapid heartbeat and losing consciousness
you're pregnant and you also have a high temperature
you're particularly frail and your general health is poor
your symptoms fail to improve within 24 hours of starting treatment with antibiotics
you have a weakened immune system
you have a foreign body inside your urinary tract, such as a kidney stone or a urinary catheter
you have diabetes
you're over 65 years old
you have an underlying condition that affects the way your kidneys work, such as polycystic kidney disease or chronic kidney disease
If you're admitted to hospital with a kidney infection, you'll probably be attached to a drip so that you can be given fluids to help keep you hydrated. Antibiotics can also be given through the drip.
You'll have regular blood and urine tests to monitor your health and monitor how effectively the antibiotics are fighting off the infection.
Most people respond well to treatment. As long as there are no complications, they're usually well enough to leave hospital within three to seven days.