Most people have two kidneys and they are found at the back of the abdomen, level with the bottom rib on either side of the body. The main job of the kidneys, is to clean the blood, removing waste material that is produced by the body and any water that is not needed. These waste products are turned into urine. From the kidneys, the urine moves down a tube called the ureter into the bladder. When you go to the toilet, the urine is passed out of the body by contractions of the bladder through a single tube called the urethra.
This urinary system (kidneys, ureters, bladder and urethra) can get infected. Infection of the kidneys is called pyelonephritis. One or both kidneys can be infected The symptoms you may feel if you have a kidney infection include back pain, side pain and loin pain. You may have a desire to pass urine frequently and urgently. You may experience pain or burning when you do pass urine. You may feel sick and you may also have a temperature.
Pyelonephritis is caused by bacteria, most often from the bowel, entering the urinary system from the outside, up the urethra, into the bladder and then up one or both ureters to the kidneys. Prostatism and kidney stones can also cause infection as they prevent efficient flow of urine from the bladder.
The infection occurs more frequently in women than in men simply because the opening of the urethra in women is closer to the anus and the bacteria from the bowel.
For some children and adults kidney damage is caused by a condition called reflux nephropathy. This is a combination of two problems that make infection more likely to occur.
Firstly, there are little valves at the ends of the two ureters where they join the bladder. These are supposed to prevent urine that has drained from the kidneys being allowed back up the ureters to the kidneys. These valves do not always work properly. When the bladder contracts to push the urine out of the body through the urethra, they allow some urine to escape up into the kidneys again.
Secondly, the bladder may not empty properly each time the child goes to the toilet. With the stale urine that has not emptied out going up, into to the kidneys, the chances of infection are increased causing pyelonephritis.
For others the damage is caused by infections of the kidney in childhood that went unnoticed at the time. The body may not fight off the infection entirely and it can remain, without causing any symptoms that you would be aware of, for a number of years. However, its presence causes scarring of the kidney which distorts and destroys parts of the kidney. For most children, teenagers and women the infection does not progress and it is eradicated by the body. The damage done does not affect the ability of the kidneys to do their job. But, in a few people, the continuous destruction of the kidney leads to chronic renal failure which will require treatment.
There are two parts to the treatment. Firstly, the Doctor finds out exactly which bacteria is causing the infection in order to kill it and stop further damage. Secondly, the Doctor finds out how the infection happened in order to reduce the risk of another occurring and to assess how much damage has been caused.
In order to discover the type of bacteria the patient is asked to give a specimen of urine. This is sent to the laboratory which identifies the bacteria allowing the Doctor to prescribe the right antibiotic.
Once treatment has started the Doctor will want the patient to have a couple of tests to find out why the infection happened and any damage that may have occurred. Usually, the patient is sent for an ultrasound scan or an x-ray of the kidneys. Ultrasound is a painless procedure that uses sound waves to build up a picture of your kidneys. The x-ray involves injecting a special dye into a vein in the arm. The body naturally removes the dye from the blood through the kidneys into the urine. The dye shows up the structure of the kidney when an x-ray is taken as this is happening.
Untreated infection can sometimes stop on its own but, if it persists, it may lead to scarring and damage of the kidneys. Damaged kidneys can cause other conditions, for example, high blood pressure which can be the result of kidney disease. For some, chronic renal failure may be the result, requiring frequent medical attention in adult life.