Definition
Urinary tract infection in the narrower sense refers to what is commonly known as cystitis. The technical term for this is cystitis. However, urinary tract infections can actually – as the name suggests – affect the entire urinary tract system.
A distinction is therefore made between upper and lower urinary tract infections. While cystitis and urethritis are called lower urinary tract infections, upper urinary tract infections include involvement of the ureters and/or kidneys (inflammation of the renal pelvis). The inflammation of the bladder is a very common clinical picture that occurs more frequently in women.
Inflammation of the renal pelvis can result from an untreated inflammation of the bladder. Urosepsis also arises from an untreated cystitis and is potentially life-threatening. Nevertheless, cystitis does not always have to be treated with medication.
Causes
A urinary tract infection is caused by an infection. An infection in turn is caused by a colonization of the body or a part of the body with bacteria. In all types of urinary tract infections, including cystitis, bacteria that rise up the urethra into the bladder are the most common trigger of infection.
An upper urinary tract infection can develop from an untreated lower urinary tract infection. The bacteria continue to rise from the bladder into the urinary tract and thus reach the ureter (urethra) or even the kidneys. While a simple cystitis is often a harmless clinical picture, the upper urinary tract infection can lead to an inflammation of the renal pelvis which is accompanied by severe general symptoms.
A urinary tract infection can also develop into a so-called urosepsis. In sepsis, the bacteria enter the bloodstream and this leads to a kind of infection of the whole body. Sepsis is a life-threatening clinical picture that requires urgent treatment.
There are risk factors that favour the occurrence of a urinary tract infection. These include malformations of the urinary tract system, which are most common in small boys, enlargement of the prostate (prostate hyperplasia), which is common in older men, urinary stones, poor intimate hygiene, urinary catheters, diabetes mellitus and the female sex. The fact that the female sex is considered a risk factor for the development of a urinary tract infection is due to the fact that a woman’s urethra is significantly shorter than that of a man.
This makes it much easier for bacteria from outside to enter the bladder. Cold, or cold feet, can also promote cystitis. Escherichia coli (abbreviated E. Coli) is a gram negative bacterium.
It is mainly found in the intestinal flora, i.e. in the gastrointestinal tract. In healthy patients who live at home, the most common cause of a urinary tract infection caused by E. coli is incorrect intimate hygiene. In this case, bacteria from the anal area can move forward into the urinary tract and then ascend into the bladder.
This usually happens much more frequently in women than in men because the urethra of women is much shorter. E. coli is the most common cause of urinary tract infections acquired in the home (outpatient acquired urinary tract infections). In about 70% of these outpatient urinary tract infections, E. coli is the detected bacterium.
Bacteria from the group of enterobacteria are more rarely found. For example Klebsiellen or Proteus species. Staphylococci and enterococci also occur.
Urinary tract infections acquired during a stay in a care facility (e.g. hospital) are called nosocomial urinary tract infections. Here the most common pathogens are Klebsiellen, Proteus and Pseudomonas aeruginosa. However, E. coli is also frequently found.
There are germs that are transmitted during sexual contact and can cause a lower urinary tract infection. These include above all Neisseria gonnorhoeae, the cause of gonorrhoea (gonorrhea), and Chlamydia trachomatis. A urinary catheter is a thin, flexible tube that is pushed from the outside through the urethra into the bladder.
The purpose of the catheter is to drain the urine from the bladder to the outside. This can be useful, for example, in patients with neurological disorders that affect urination, in old incontinent patients or during surgery with subsequent immobility. Even if the urinary catheter is placed under sterile conditions, it is a potential source of infection.Bacteria from the outside can rise through the tube in the urethra and into the bladder, causing an inflammation.
Urinary catheters should therefore only be left in place for as long as absolutely necessary. The longer the catheter is in place, the higher the risk of infection. An alternative for patients who permanently need a bladder catheter is the so-called suprapubic urinary catheter.
It is not inserted into the bladder through the urethra but through an incision above the pubic bone. The risk of infection is lower with this type of catheter. In addition, a daily sufficient hygiene of lying bladder catheters and the intimate region of the patient should be carried out to minimize the risk of infection.
Bladder catheters are the most common cause of urinary tract infections in hospitals (nosocomial urinary tract infections). Even if such a urinary tract infection sounds like a rather banal disease at first, it should not be underestimated. Such an infection can develop into life-threatening urosepsis, especially in patients with serious pre-existing conditions or a weakened immune system.
