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Kidney Infection

Kidney Infection Is a Serious Condition

Kidney infection

Kidney infection is the invasion of one or both kidneys by Pathogens, which cause injury to the affected area(s).  It is an infection that occurs within the kidneys, medically known as pyelonephritis (PI-low-nef-ri-tis).

An infection can occur almost anywhere in the urinary tract. An Infection of the urinary tract is referred to as urinary tract infection.  If an infection occurs in the bladder, it is generally referred to as a bladder infection, medically known as cystitis (cis-TIE-tis).


The focus of this article, however, is primarily on kidney infection (or infection that occurs within the kidneys themselves).

Pathogens are toxins, organisms (such as bacteria, viruses and fungi) and other agents that cause disease. Primarily, however, infection of the kidneys is caused by bacteria.

How Do Kidneys Become Infected?

Bacteria are the main cause...  While there are other causes  of kidney infection, bacteria are the predominant cause.  These particular bacteria live in the colon and are called the Escherichia coli (E. coli) bacteria.  


How do these bacteria, which normally live in the colon, find their way to the kidneys?

There are two (2) main ways in which bacteria can enter the kidneys:

  1. The first is through blood that has been infected by bacteria. As the kidneys filter blood, removing excess water, salt and other nitrogenous wastes (such as uric acid and urea), bacteria present in the infected blood can get into the kidneys.  If the bacteria remain long enough in the kidneys, they can infect them and cause inflammation and kidney damage.

  2. The second way by which bacteria usually enter the kidneys is through 


​infected urine that is either stagnated (mainly due to blockage within the urinary tract), or urine that flows in the wrong direction (from the bladder to the kidneys - as is the case with kidney reflux disease).

If the E. coli bacteria get into the urethra it can find its way into the kidneys. Some common ways in which bacteria can get into the urethra are through sexual intercourse, wiping from back to front (especially females), waiting too long to urinate (causes urine stagnation), and external objects such as diaphragms (for birth control). Women, in particular, are susceptible to infections via these channels.

If these bacteria remain long enough in the urethra and are allowed to multiply, they can move up into the bladder then into the ureters and eventually into the kidneys. This is especially likely to happen if urine flows backward, in the wrong direction.

How Can You Know if You Have Kidney Infection?

Kidney infection symptoms

The symptoms of kidney infection are usually very noticeable and can be rather severe.   In some cases, the onset of symptoms can be quite sudden (acute), especially if infection is caused by bacteria in the blood.

When infection begins in other areas of the urinary tract (excluding the kidneys) the initial symptoms may be mild and, in some cases, hardly noticeable.

It is important, however, not to ignore early warning signs of urinary tract infection (UTI).  Recognition of these early warning signs is important since it can help to expedite the diagnosis and treatment of UTI, before the infection spreads to the kidneys.


Kidney infection is a serious kidney condition and requires prompt treatment in order to minimize damage to the kidneys.  If the condition is allowed to persist, kidney damage can be severe leading to kidney impairment and, eventually, kidney failure.​

Early symptoms may include some (or all) of the following:

  • The urge to urinate frequently.  (This may also result in urinary incontinence);

  • Passing only small amounts of urine, despite the frequent urge to urinate;

  • Pain or burning in the bladder or urethra during urination;

  • Uncomfortable pressure or pain around the pubic area;

  • Cloudy or milky-looking urine.

When the kidneys become infected, the symptoms are much more severe and, in addition to the symptoms listed above, may also include the following:

  • Fever;

  • Severe pain in the lower back or sides (below the ribs);

  • Vomiting and nausea;

  • Headaches;

  • Feeling tired and weak.


Remember, effective, early treatment is essential to avoid or minimize kidney damage.  So pay attention to any early symptoms of UTI.  If you suspect that you may have a kidney infection or a urinary tract infection, visit your doctor without delay.

How Is Kidney Infection Treated?

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