In 1808 Philip Syng referred to cystitis as "an inflammatory condition of the bladder with an ulcer producing the same symptoms as a bladder stone".
Joseph Parrish referred to urinary tract infection in 1836 as: "A painful tic of the urinary bladder" and Skene in 1887 as "An inflammation that has destroyed the mucous membrane partly or wholly and extended to the muscular parietes" (Bschleipfer 2018).
A urinary tract infection (UTI) is the presence of infectious agents in the urinary tract, which may present with or without symptoms (Herold 2020).
In the case of UTI, one differentiates between:
In the literature, however, the terms "complicated" and "uncomplicated" are not treated consistently (Schmelz 2014).
Up to the age of 50, UTI occurs almost exclusively in women. Approximately 60 % of all women suffer from a symptomatic UTI at least once in their lifetime. UTI is the most common nosocomial infection and is the most common cause of incapacity in women (Herold 2020). Among adult women, between 20%-30% develop acute cystitis ≥ 1 time per year (Schmelz 2014). The following peaks of illness are found in UTI:
1. in infancy and early childhood
2. during the honeymoon (so-called honeymoon cystitis)
3. during pregnancy
4. in the postpartum period: in women, the prevalence increases with age (Herold 2020). In men, HWIs occur only from about the age of 50 and are predominantly obstructive due to prostate disease (Kuhlmann 2015).
5. Z. n. kidney transplantation: UTI is the most common bacterial infection in patients with Z. n. kidney transplantation with 45% - 72% (Guberina 2016) (Keller 2010). In the 1st year after transplantation - especially in the first 3 - 6 months - HWIs occur frequently (Kuhlmann 2015).
Asymptomatic bacteriuria in women is found in:
Among sexually active women between 20 - 45 years of age, symptomatic cystitis develops later in about 8%. In women without pre-existing asymptomatic bacteriuria, the prevalence of cystitis is only 1% (Manski 2019). Untreated asymptomatic bacteriuria in pregnant women leads to acute pyelonephritis in up to 30% (Herold 2020). Patients with indwelling catheters also frequently have asymptomatic bacteriuria, which also remains asymptomatic in the further course (Manski 2019).
In women, causal anatomical conditions play a major role such as:
In men, there is some protection against cystitis due to:
In approx. 50 % of HWIs bacteria are found as cause:
Uncomplicated UTI: Uncomplicated UTI is caused by E. coli in up to 80% of cases (Herold 2020).
Complicated UTI: In complicated UTI, enterococci are present in 30%, E. coli and staphylococci in 20% each, Pseudomonas aeruginosa in 10%, and Proteus mirabilis, Klebsiella, and other germs in < 5% each (Herold 2020).
UTI in patients after kidney transplantation: Gram-negative pathogens and enterococci are predominant (Kuhlmann 2015).
Nosocomial UTI: In the case of nosocomial UTI, mixed infections with problem germs such as:
In patients with permanent catheters, 50 % have a UTI after only 1 week, and almost 100 % after 1 month. These are predominantly mixed infections. Candida is found in the urine of approx. 20 %, but there are mostly no symptoms.
Risk factors for a urinary tract infection are:
All other factors such as pre- or post-coital urination, use of tampons, warm baths, showering behaviour, frequency of micturition, type of underwear, etc. have not yet been proven in studies (Kuhlmann 2015).
At the beginning of the inflammation, hyperemia, edema and infiltration of the bladder wall occur in the urinary bladder due to neutrophilic granulocytes. In the further course, the mucosa is replaced by an easily injured granulation tissue. Occasionally, shallow ulcers filled with exudate develop there. The inflammation usually affects only the mucosa and submucosa. All layers of the muscularis are rarely affected.
Without treatment, hemorrhages and necroses of the bladder wall occur in the late stage of the disease (Manski 2019).
UTI can present clinically in completely different ways:
Asymptomatic bacteriuria: This is usually an incidental finding. In this case - despite normal urine sediment and absence of symptoms - bacteriuria is detectable. There are no symptoms (Herold 2020).
Symptomatic U TI: In symptomatic UTI, a distinction is made between an uncomplicated and a complicated form and between different degrees of severity.
- Uncomplicated U TI: In this case, predisposing factors are usually absent and a monoinfection is present (for more details, see "Etiopathogenesis" above).
- Complicated U TI: In complicated UTI, predisposing risk factors are present and a mixed culture is present (for more details, see "Etiopathogenesis" above).
One differentiates between 3 degrees of severity:
The cardinal symptoms in symptomatic UTI are (Mader 2019): dysuria, pollakiuria.
Acute cystitis: Acute cystitis usually starts suddenly. The cardinal symptoms are:
The following symptoms may also occur:
In renal transplant patients, UTI can be completely asymptomatic (Konik 2020).
The diagnosis depends on various factors and includes in V. a.:
Asymptomatic bacteriuria. In this case, screening should be done only in pregnant women.
Symptomatic UTI (except in healthy non-pregnant pre-menopausal women): Urine culture.
Complicated UTIs in men: urinalysis, sonography, prostate exam
Recurrent U TIs (Herold 2020): urine culture, one-time sonography
Acute cystitis: According to the S3 guideline of the DGU, no further diagnosis is necessary in the following cases (Manski 2019):
(for more details see below "Imaging" and "Laboratory")
ACSS- questionnaire: In 2015, Alidjanov et al. presented the ACSS- questionnaire (Acute Cystitis Symptom Score) to validate uncomplicated acute cystitisin women.
Sonography: On sonography of the urinary bladder and kidneys, there may be any evidence of (Manski 2019):
Urogram: In case of recurrent cystitis that showed abnormalities on sonography (such as urinary retention, urinary bladder diverticulum, infectious stones, ureterocele, etc.), it is recommended to perform a urogram (Manski 2019).
Cystoscopy: Cystoscopy should be performed exclusively in the infection-free interval (Manski 2019). Routinely, according to the S3- guideline , it is not recommended in women without other relevant concomitant diseases, even in the case of recurrent urinary tract infections, but it is recommended above a certain age (not further defined) and in the case of complications such as microhematuria, detection of pathogens other than E. coli, etc.
Contrast-enhanced CT: If sonography reveals an unclear finding, CT is recommended. This can detect:
MRI: MRI is indicated in patients with contrast allergy or to iodine-containing contrast agents (Herold 2020).
Micturition cystourethrography (MCU): Retrograde micturition cystourethrography can provide morphologic and functional information about the lower urinary tract (Sigel 2013). Indications include:
Blood test: Blood tests are not usually necessary for uncomplicated UTI, but are necessary for suspected pyelonephritis. If sepsis is suspected, blood cultures should be obtained immediately. Symptomatic UTI of severity II or higher may cause renal function impairment (see "Clinical picture" above for details), which can be detected by laboratory tests (Herold 2020).
Urine test strip: A positive test strip increases the likelihood of cystitis. However, since both sensitivity and specificity are insufficient, the test strip is not recommended for the diagnosis of cystitis according to the S3- guideline (Wagenlehner 2017).
Urine sediment: Nowadays, automated sediment analysis (with particle counter) is increasingly used (Wagenlehner 2017). This can be used to detect bacteriuria, micro- or macrohematuria, pyuria, and positive nitrite in the presence of high bacterial counts (Manski 2019).
1. bacteriuria: urine should be obtained before starting antibiotics.
The prerequisites for correct collection are spreading of the labia, careful cleaning of the meatus urethrae or glans penis. Subsequently, midstream urine can be obtained. Prerequisites for the correct interpretation of the findings are rapid transport by cold chain, the use of special media or immediate processing.
As a general rule, urine should not be collected from catheter bags for further examination (Herold 2020).
1a. Midstream urine: According to Kass, one speaks of a significant bacteriuria if a bacterial count of ≥ 105 / ml urine is found in the midstream urine after appropriate processing. Lower bacterial counts indicate contamination.
An exception is made for patients with typical symptoms of a UTI who have been treated. Here, bacterial counts ≤103 to 104 / ml urine are also considered pathological (Herold 2020).
1b. Bladder puncture urine: In urine obtained by bladder puncture, any detection of germs is considered pathological.
In cases of recurrent HWIs with evidence of enterococci or a mixed infection in midstream urine, bladder puncture is recommended because contamination is often present (Herold 2020)
For any significant bacteriuria (definition see above 1a. and 1b.), a germ differentiation with antibiogram should be created (Herold 2020).
Leukocyturia: leukocyturia is an indication of pyelonephritis: leukocyturia in otherwise sterile urine (so-called sterile leukocyturia) can be caused by:
Urine culture: Urine culture is recommended for:
For a urine culture, midstream urine is required (see "Urine sediment" above). Pathogen counts of > 105 germs / ml indicate cystitis. A bacterial count of 103 to 104 germs / ml is already relevant if clinical symptoms are present at the same time. It should be noted that forced diuresis can also result in falsely low bacterial counts. The detection of pathogens in a urine sample obtained by bladder puncture or disposable catheterization is always considered pathological. In permanent catheter users, a bacterial count of > 104 plus leukocyturia of > 100 / µg is considered a significant infection (Manski 2019).
Recurrent cystitis (Herold 2020).
Hematuria to macrohematuria (Kasper 2015).
Pyelonephritis due to ascension of pathogens. Occurs in < 5% of all patients with acute cystitis (Manski 2019 / Schmelz 2014)
paranephritic abscess (CT).
In pregnant women:
Asymptomatic detection of germs:
The following patients with asymptomatic detection of germs do not require screening or antibiotic treatment:
Treatment of asymptomatic bacteriuria is always required in:
Symptomatic germ detection. If the course is mild, it may be possible to wait with antibiotics (initially). The patient should be advised to
If there is no improvement under this, antibiotic treatment is required (Manski 2019).
Uncomplicated acute cystitis in women can be treated with short-term oral antibiotic therapy (1 - 3 days).
The S3- guideline primarily recommends agents that show a low resistance rate, do not play a role in severe infections, and are sensitive to the typical pathogen spectrum in women in Germany.
The 1st choice agents include:
In uncomplicated cystitis (see "Classification") should NOT be used as a 1st choice agent:
The 3rd choice agents (due to side effects) include:
(Complicated) acute cystitis in pregnant women: In pregnancy, even asymptomatic bacteriuria should be treated with antibiotics, otherwise the risk of complications (see above "Complications") increases. Antibiotics that can be used are:
(Complicated) cystitis in postmenopausal women: There are few studies that have investigated the efficacy of short-term therapy in postmenopausal women. The choice and efficacy of each antibiotic is similar to that of uncomplicated premenopausal UTI, but the duration of therapy should be extended if necessary.
(Complicated) acute cystitis in younger men: Since this occurs only very rarely, there are few meaningful comparative studies. In symptomatic cystitis, oral drug treatment with the following antibiotics is recommended - after obtaining a urine culture - (and adjusted if necessary after obtaining the antibiogram):
It remains open - according to the S3- guideline - whether a complete urological examination should be performed in uncomplicated cystitis in younger men. In any case, this is recommended in:
UTI in patients with kidney transplantation:
Asymptomatic bacteriuria: The question whether asymptomatic bacteriuria after kidney transplantation should be treated with antibiotics is controversial. Retrospective studies have shown that asymptomatic bacteriuria correlates with high rejection rates. Therefore, it is recommended to treat patients with antibiotics during the first 1-3 months. However, a recent prospective randomized study of 112 transplanted patients (Origüen 2016) failed to demonstrate a clear benefit.(Guberina 2016).
UTI: U TIs are more common in patients with renal transplantation, simply because of immunosuppression (Guberina 2016). Pyelonephritis can lead to a significant deterioration in graft function, which is only partially reversed even after successful treatment (Kuhlmann 2015). If a UTI occurs immediately after transplantation, initial parenteral antibiotics appropriate to resistance are required. Further treatment can be oral and should continue for at least 6 weeks (Keller 2010). Within the first 3 months after transplantation, 6 weeks of oral therapy is recommended according to the antibiogram. If an UTI occurs later than 6 months after transplantation, a 10-14 day treatment period is usually sufficient (Keller 2010). In the case of symptomatic UTI, the initiation of antibiotics is recommended from > 103 germs / ml. After the urine culture has been taken, the following antibiotics can be administered:
In mild cases e.g.:
For severe infections, e.g.:
For multidrug-resistant bacteria, e.g:
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"Essen algorithm for the calculated antibiotic treatment of urinary tract infections in kidney transplant patients".
The algorithm was first presented in 2011 for the calculated antibiotic treatment of kidney transplant patients. It considers gram-negative germs in addition to enterococci occurring in the early phase. It recommends the use of quinolones (gyrase inhibitors) in the first two months after transplantation and then cephalosporins from the third month onwards. Treatment should be started parenterally in cases of severe infection and continued orally (Becker 2011).
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UTI with Candida:
Treatment of asymptomatic candiduria is recommended only when
For susceptible Candida species, treatment should be with:
The spontaneous healing rate of an uncomplicated UTI is between 30 % - 50 % within one week (Herold 2020). In the case of a UTI treated with antibiotics, the following symptoms should appear after 24 hours:
The urine should be sterile again after 3 days. If this is not the case, there are probably complications (see above / Herold 2020).
The prognosis of HWI treated with antibiotics is good overall. In recurrent UTIs, the risk of transition to chronic pyelonephritis (CPN) is relatively low, provided there are no predisposing factors such as vesicoureteral reflux, obstruction, etc.
For the prevention of recurrent cystitis are recommended:
Recurrent urinary tract infections in postmenopausal women can be reduced by vaginal estrogen replacement therapy in the form of ointment, capsule or ring