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Urinary Tract Infection (Classification (Uncomplicated: normal urinary…
Urinary Tract Infection
- an infection in one or more parts of the urinary system that occurs as a result of microorganisms (bacterias, viruses, chlamydias, fungi) invasion and growing in the urinary tract.
- common in women
Pathogenesis
Impaired host defence
- Neutrophils activity is essential for bacterial killing.
- Urine osmolality and pH ( >800 mOsm/kg and low or high pH reduce bacterial survival)
- IgA production by uroepithelium
- Commensal organisms (lactobacilli, corynobacteria, streptococci) prevent pathogens growth
- Urine flow (wash out pathogens)
- Proteins of mucus covering uroepithelium : Tamm-Horsfall protein (prevent bacterial binding)
High virulence
- High virulence = High ability of pathogens to adhere to epithelial cells
- E. Coli with type 1 fibriae (FimH adhesin) associated with cystitis
- E. Coli with type P fimbriae (PaPg adhesin) - higher virulence, responsible for pyelonephritis
Risk/modulating factors
- Women, Pregnancy, Congenital abnormalities e.g. duplex kidney, sexual intercourse ( honeymoon cystitis).
- Stasis of urine e.g. due to poor bladder emptying, Foreign bodies eg catheters, stones
- Fistula between bladder & bowel
- Immunosuppression, Steroids, Malnutrition, Diabetes, Renal diseases
- Pathogen transfers to the urinary tract:
1.ascending transurethral route
2.via the bloodstream
3.via limphatics
4.by direct extension (e.g. from a vesicocolic fistula).
Classification
- Uncomplicated: normal urinary tracts
- Complicated: Abnormal urinary tracts
• obstruction or other structural factor (urolithiasis, malignancies, strictures, bladder diverticuli, renal cysts, enlarged prostatae)
• functional abnormality: neurogenic bladder, vesicoureteral reflux
• foreign bodies: catheter, nephrostomy tube
• other conditions: renal failure, diabetes, renal transplantation, hospital acquired infection, pregnancy (preterm).
- Isolated (90%):the first UTI and isolated from the previous UTI by at least 6 months
- Recurrent (relapse, reinfection): at least 2 UTI in 6 months, or 3 UTI in 1 year
RELAPSE – recurrence of bacteriuria with the same organism within 14 (7) days of completion of antibacterial treatment (implies failure to eradicate infection, the presence of sequestered
focus in kidney or in prostate) - 20%
REINFECTION – recurrence of bacteriuria with the same or different organism after this time (80%) the therapy has successfully eradicated the infection, there is no sequestered
focus, but uropathogens are reintroduced from the fecal reservoir).
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- Asymptomatic bacteriuria
- Urethritis
- Cyctitis
- Pyelonephritis
- Lower: urethritis, cystitis, prostatitis
- Upper: pyelonephritis, intrarenal and perinephric abscess
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Clinical manifestation
- a frequent urge to urinate
- a painful, burning feeling in the area of the bladder or urethra during urination (dysuria)
- despite the urge to urinate, only a small amount of urine is passed
- hematuria, fever, suprapubic pain
- high fever, chills, pain in the back or side below the ribs, nausea, or vomiting (kidney involvement – acute pyelonephritis)
Laboratory findings
- urine culture: (bacteriuria)* - fundamental marker !!!!
- special culture for Chlamydia trachomatis, Ureaplasma urealyticum i Mycoplasma hominis
- urine dipsticks (screening method):
postive test for leukocytes (leukocyte esterase,) ;
positive Griees nitrate reduction test (identifying Enerobacteriaceae infection)
- urinanalysis: pyuria: >10 wbc/high-power field, hematuria
- pH urine: alkaline ph with urea splitting bacteriae (urea converted to ammonia)
Bacteriuria
- SYMPTOMATIC WOMEN: >100 E. Coli/ml urine + pyuria
or >100 000 any pathogenic organism/ ml urine or
any growth of pathogenic organisms in urine by suprapubic aspiration
- SYMPTOMATIC MEN – > 1000 any pathogenic organism/ ml urine
- ASYMPTOMATIC PATIENT – > 100000 any pathogenic organism/ ml urine on two occasions
- Lesser numbers of CFUs, polimicrobial culture - probably refelects contamination
Urethral syndrome
- abacteriuric dysuria
- Postcoital bladder trauma, Tuberculosis
- Vaginitis, Atrophic urethritis in the elderly
- Chlamydia, Ureoplasma infection, Intersitial cystitis
- Others (cystes, obstruction)
Interstitial cystitis
- Affecting women over 40 years old
- It presents with frequency , dysuria, severe suprapubic pain.
- Urine cultures are sterile
- Cystoscopy shows inflammmatory changes with ulcerations od the bladder base
- Autoimmune pathomechanism is postulated
Management
- A high fluid intake is encouraged (2 l)
- Vitamin C to acidify the urine
- Antiseptics (natural-herbal, methanamine, Methylenum coeruleum )
Treatment
Single dose therapy (less effective)
3-7 days therapy
14 days therapy
Longer treatment course
Drug choice: drug concentration in urinary tract (excretion of active drug)
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radiological evaluations
- Uncomplicated UTI does not require any radiological evaluations
- Reccurent UTI, Males, Children, Acute pyelonephritis, Hematuria with negative culture or persists after treatment
- Ultrasound imaging, intravenous urography, CT, contrast-enhanced CT (to exclude obstruction, calculi).
Asymptomatic bacteriuria
- The presence of significant bacteriuria accompanied by the the absence of symptoms of urine tract infection
- treatment is generaly not needed
- pregnent women, renal transplant recipients, neutropenic patients, and patients udergoing urologic infections SHOULD BE TREATED
Pregnancy
- Asymptomatic bacteriuria may lead to:
acute pyelonephritis, premature labour, Pre-eclamptic toxaemia, Small or premature babies, Anaemia
- Urine culture must be performed
- The safe antibiotics: amoxicylin, nitrofurantoin, cephalosporins
Prostatitis
- The pathogenesis is related to reflux of infected urine from the urethra into the prostatic ducts.
- Symptoms: dysuria, obstructive voiding symptoms, fever, chills, pain in penis, testicles, and areabetween the scrotum and the rectum, painful ejaculation
- Prostate is tender and swollen.
- A three-part urinalysis is the standard diagnostic tool. Two urine specimens are collected andanalyzed, followed by prostate massage and a third urine sample that contains prostatic fluid.
- The duration of treatment should be at least 30 days.
