Genitourinary infection
Background
Definitions
- UTI = significant bacteriuria in presence of symptoms
- Described by location: urethritis, cystitis, or pyelonephritis
- Relapse
- Recurrence of symptoms w/in month despite tx
- Caused by same organism and represents treatment failure
- Recurrence of symptoms w/in month despite tx
- Reinfection
- Development of symptoms 1-6mo after tx
- Usually due to a different organism
- If pt has >3 recurrences in 1 yr consider tumor, calculi, DM
- Men <50 yr: symptoms of dysuria or urinary frequency usually due to STI
- Men >50 yr: incidence of UTI rises dramatically d/t prostatic obstruction
- Uncomplicated UTI:
- No structural or functional abnormalities w/in urinary tract or kidney
- No relevant comorbidities that place pt at risk for more serious adverse outcome
- Not associated with GU tract instrumentation
Risk factors for complicated UTI
- Male sex
- In young males dysuria is more commonly d/t STI
- Suspect underlying anatomic abnormality in men with culture-proven UTI
- Anatomic abnormality of urinary tract or external drainage system
- Indwelling urinary catheter, stent
- Nephrolithiasis, neurogenic bladder, polycystic renal disease, recent instrumentation
- Recurrent UTI (three or more per year)
- Advanced age in men (BPH, recent instrumentation, recent prostatic biopsy)
- Nursing home residency (w/ or w/o indwelling bladder catheter)
- Neonatal state
- Comorbidities (DM, sickle cell disease)
- Pregnancy
- Immunosuppression (AIDS, immunosuppressive drugs)
- Advanced neurologic disease (CVA w/ disability, spinal cord injuries)
- Known or suspected atypical pathogens (Non–E. coli infection)
- Known or suspected abx resistance (resistance to cipro predicts multidrug resistance)
Bacteriology
- Most common pathogen is E. coli
- Anaerobic organisms are rarely pathogenic (do not grow well in urine)
- Complicated UTIs more likely to be caused by pseudomonas or enterococcus
Diagnosis
Clinical Features
- UTI dx requires both bacteriuria and clinical symptoms
- Cystitis = Dysuria, hematuria, frequency, urgency, suprapubic pain, CVAT
- Pyelo = Cystitis sx AND fever/chills/nausea/vomiting
- CVAT alone may be referred pain from cystitis
- CVAT is only physical examination finding that increases likelihood of a UTI
- Urethritis
- In males more likely due to chlam/GC
- In females more likely due to chlam/GC if:
- Stuttering urination symptoms
- New sex partner or partner w/ urethritis
- Signs/symptoms cervicitis
- Sterile pyuria
- Complicated UTI
- Pts may not have classic symptoms; may only have weakness, fever, abd pain, AMS
Labs
UA
WBC count
- WBC >5 in pt w/ appropriate symptoms is diagnostic
- Lower degrees of pyuria may still be clinically significant in presence of UTI sx
- False negative may be due to: dilute urine, systemic leukopenia, obstruction
- WBC 1-2 w/ bacteriuria can be significant in men
- More likely represents urethritis or prostatitis from STI
- Lower degrees of pyuria may still be clinically significant in presence of UTI sx
Nitrite
- Very high specificity (>90%) in confirming diagnosis of UTI
- Low sensitivity (enterococcus, pseudomonas, acinetobacter are not detected)
Urine Culture
- Indicated for:
- Complicated UTI
- Pyelonephritis
- Pregnant women
- Children
- Adult males
- Relapse/reinfection
Blood Culture
- Not indicated
- Organisms in blood cx matched those in urine cx 97% of time
Imaging
- Consider if pyelonephritis and any of the following:
- History of renal stone
- Poor response to abx
- Male
- Elderly
- Diabetic
- Severely ill
Treatment
- Consider local resistance patterns (if >10-20% use a different agent)
- Avoid use of fluoroquinolones for uncomplicated cystitis if possible
- Consider longer course of tx for uncomplicated cystitis if:
- Symptoms >7d
- DM
- UTI in previous 4wk
- Men
- Age 65 yr
- Women who use spermicides or diaphragm
- Relapse
Women, uncomplicated cystitis
- Nonpregnant, few prior UTI episodes, symptoms <7d, no flank pain or fever
- Nitrofurantoin ER 100mg BID x 5d OR
- TMP-SMX DS (160/800mg) 1 tab BID x 3d OR
- Cephalexin 250mg QID x 5d OR
- Ciprofloxacin 250mg BID x3d
Women, complicated cystitis/pyelo
- Risks for complicated UTI or symptoms of pyelo
- Ciprofloxacin 500mg BID x10-14d OR
- Cefpodoxime 200 mg BID x10-14d
Women, uncomplicated cystitis AND urethritis
- CTX 250mg IM x1 AND azithromycin 1gm PO x1 AND nitrofurantoin ER 100mg BID x5d OR
- Levofloxacin 500mg QD x 14d (covers UTI pathogens, GC, and chlam)
- GC resistance to fluoroquinolones is increasing
Men, cystitis/pyelo
- Consider urethritis and prostatitis
- Ciprofloxacin 500mg BID x10-14d OR
- Cefpodoxime 200 mg BID x10-14d
Inpatient
- Ciprofloxacin 400mg IV q12hr OR
- Ceftriaxone 1gm IV QD OR
- Cefotaxime 1-2gm IV q8hr OR
- Gentamicin 3mg/kg/day divided q8hr +/- ampicillin 1–2 gm q4hr OR
- Piperacillin-tazobactam 3.375 gm IV q6hr OR
- Cefepime 2gm IV q8hr OR
- Imipenem 500mg IV q8hr
Disposition
Uncomplicated UTI
- Admit
- Unable to tolerate PO
- Discharge
- Consider phenazopyridine 100-200mg TID after meals x2d only (bladder analgesic)
Pyelonephritis
- Discharge
- Consider if young, otherwise healthy, tolerating PO
- Admission
- Consider if elderly, calculi, obstruction, recent hospitalization/instrumentation, DM
Complications
- Suspect in pts who have inadequate or atypical response to tx for presumed pyelo
- Acute bacterial nephritis
- CT shows ill-defined focal areas of decreased density
- Renal/Perinephric abscesses
- Sign/symptoms similar to pyelo (fever, CVAT, dysuria)
- Occurs in setting of ascending infection w/ obstructed pyelo
- Associated w/ DM and renal stones
- Also occurs due to bacteremia w/ hematogenous seeding (Staph)
- Emphysematous pyelonephritis
- Rare gas-forming infection nearly always occurring in pts w/ DM and obstruction
- Pts appear toxic and septic; nephrectomy may be required
- Rare gas-forming infection nearly always occurring in pts w/ DM and obstruction
Special Populations
AIDS
- TMP-SMX resistance is increased due to its use in PCP PNA prophylaxis
- Fluoroquinolones should be initial antibiotic of choice
- Most UTIs are caused by typical pathogens or common STI organisms
Pregnant Women
- Treat all cases of asymptomatic bacteriuria
See Also
Source
Tintinalli