Urinary Tract Infection

Urinary tract infections are common presentations to the family physician's office. It is important to delineate which UTIs are complicated, require further investigations, and management.

History

 * Cystitis: dysuria, urgency, frequency, suprapubic pain/tenderness, new onset confusion
 * Urethritis: similar symptoms to cystitis - urethral d/c may be present
 * Pyelonephritis: cystitis symptoms, + systemic manifestations - fever, rigors, change in mental status, flank pain, costovertebral tenderness, hematuria, pelvic discomfort, N/V
 * Renal abscess: pyelo symptoms that persist despite abx
 * Past medical history: prior history of UTI, catheter, renal anomalies, immunosupression, history of incontinence, spinal cord injury, neuromuscular disorders, diabetes, renal stones
 * Medications: recent abx use
 * Allergies
 * Social history - including sexual history as STIs can present with similar Sx
 * Review of systems: vaginal symptoms, BMs
 * In a child < 3 years old with fever but no apparent source - suspect UTI
 * In elderly patients/young patients with non-specific complaints e.g. abdominal pain, fever, delirium, irritability, urinary retention, incontinence always consider UTI as part of the differential

Risk factors

 * female, frequent sexual intercourse, catheter use, vesi-ureter reflux, posterior urethral valves, neurogenic bladder (e.g. spinal cord injury), diabetes mellitus, immunosuppresion, gyne prolapse, estrogen deficiency, benign prostate hyperplasia

Common pathogens
KEEPS Other:
 * 1) Klebsiella
 * 2) E.coli
 * 3) Enterococci
 * 4) Proteus, pseudomonas
 * 5) Staph saprophyticus
 * 1) Candida - common colonizer or urinary tract in hospitalized patients. Often does not require treatment
 * 2) Staph aureus - always do blood cultures as uncommon in absence of catheter/instrumentation --> consider hematogenous spread
 * 3) Urethritis: chlamydia, gonorrhea, trichomonas, HSV, ureaplasma, mycoplasma genitalium
 * 4) Coagulase -negative staphylococcus (other than staph saprophyticus) rarely cause UTIs and generally do not require treatment

Physical

 * Vitals
 * General
 * Abdominal exam - CVA tenderness, DRE (if thinking prostatitis)
 * +/- pelvic exam

Investigations

 * NOT suggestive of UTI: foul smelling, cloudy urine, change in color, + urine dip without symptoms of UTI, pyuria/bacteriuria without signs/symptoms of UTI
 * Urinalysis and microscopy can rule OUT a UTI. Not rule in. Leuks - inflammation, Nitrites - presence of certain bacteria (not necessarily an infection).
 * Nitrites can be falsely negative if frequent bladder emptying
 * Nitrates negative in gram positive bug
 * If uncomplicated risk of UTI--> do scoring system
 * 1 point for each - dysuria, leuks +, nitrites +
 * 0-1 point --> send for culture
 * 2-3 points--> start empiric therapy without waiting for culture
 * Investigations:
 * Blood pressure
 * Urinalysis
 * Urine culture - clean catch, not toilet trained: urethral catheterization (NO urine bags)
 * Sterile pyuria- can indicate urethritis, STI, nephritis, foreign body
 * Cr, EGFR (if required for abx dosing, assess for acute kidney injury)
 * Blood culture - complicated UTI or toxic appearing
 * Chlaymdia/gonorrhea testing (see STI) if high risk
 * Screen for asymptomatic bacteruia in all pregnant women and those undergoing urologic surgery
 * Renal ultrasound +/- Voiding cystourethrogram
 * Renal ultrasound: hydronephrosis, renal abscess, anatomic anomalies
 * Voiding cystourethrogram: reflux (grading system - need for UTI prophlaxis and referral)
 * First UTI in male
 * First UTI in female < 3 years old or second UTI in female >3 years old
 * Complicated pyelonephritis
 * Family history of renal anomalies/recurrent UTIs esp. with HTN or poor growth
 * Recurrent UTI
 * CT renal: if no improvement in symptoms in 72 hours and want to r/o abscess, r/o struvite stone

Recurrent

 * Two uncomplicated UTIs within 6 months OR 3+ urine cultures within 12 months

Reinfection

 * Occurs within 2 weeks of completing Abx (different organism)

Relapse

 * Occurs within 2 weeks of completing Abx (original organism)

Uncomplicated cystitis

 * cystitis in non-pregnant, non-immunocompromised host, without underlying structural/neurological d/o

Complicated cystitis

 * structural/functional abnormalieis of renal system: obstruction (stones), catheter, spinal cord injury, neurogenic bladder, polycystic kidney disease
 * UTI in men
 * Pregnancy
 * Diabetes mellitus, immunosuprresion
 * Neonate

Treatment

 * Treatment should only be considered if 1) signs and symptoms of UTI and 2) leuk esterase or WBC in urine +/- nitrates
 * Always consider local resistance patterns and patient's recent ABx use when prescribing
 * Aminoglycosides, cephalosporins, fluroquinolones and trimethoprim-sulfamethaxazole DO NOT COVER enterococcus
 * Ciprofloxacin and TMP-SMX do not reliably cover e.coli

Asymptomatic bacteriuria

 * NO treatment even in catheter patients
 * Exception: pregnant women, about to undergo urologic surgery

Non-neuropenia Adult Patients without systemic signs/symptoms (no catheter)

 * Order urine R+M, C+S
 * Antibiotic options (tailor to culture susceptability)
 * Amox/clavulin 500mg PO TID or 875 mg PO q12 hours
 * Cephalexin 500mg PO q6 hours
 * Nitrofurantoin (Macrobid) 100mg PO BID
 * TMP-SMX 1 DS tab PO q12 hours
 * Ciprofloaxin 500mg PO q12 hours (reserve for severe or pseudomonal coverage)
 * Fosfomycin 3 grams dissolved in 1/2 cup water Po x 1 dose
 * Duration of therapy:
 * Risk factors (male, neurogenic bladder, immunosuppressive therapy, GU structural abnormalitiy e.g. non-obsturcting stone) --> Male 7 days, Other: 5-7 days for fluroquinolone, TMP/SMX, nitrofurantoin or 7-10 days with beta-lactam. Note some patients may require longer treatment
 * No risk factors: 3 days (fluroquinolone or TMP/SMX), 5-7 days (nitrofurantoin), 7 days (beta-lactam)
 * Adjustments: require renal adjustments. Do not rx nitrofurantoin if CrCl <60ml/minute

Non-neutropenic Adult Patients with systemic signs/symptoms (no catheter)

 * Order blood cultures x 2, Urine R+M, C+S.
 * Antibiotic options
 * CiprofloxacinPO/IV q 12 hours
 * IV gentamycin 3mg/kg IV q 24 hours (tobra/amikacin) + ampicillin 1 gram IV q 6 hours
 * If CrCl < 40 ml/min or age >75 ceftraixone 1 gram IV q 24hours
 * If risk factors for pseudomonas: tobramycin 3mg/kg IV q24 hours or ceftazadine 1-2gram IV q8 hours or cipro
 * Duration of therapy:
 * Female: fluroquinolone (7 days), other (10-14 days)
 * Male: 10-14 days
 * Switch to PO: hemodynamicallys table, clinically improving, able to tolerate PO, functioning GI tract

Catheter related UTI

 * Symptoms of rigors, delirium, new CVA tenderness, fever (cannot rely on dysuria, urgency, frequency)
 * None of the above--> no investigations, no treatment, look for alternative etiology, remove catheter if possible
 * Yes--> remove/change catheter, send urine R+M, C+S
 * If mild-moderate: (use different abx class than that used in last 3 months)
 * amoxicillin/clavulanic acid
 * Trimethoprim/sulfamethoxazole
 * If severe (draw blood cultures)
 * PO/IV cipro
 * IV gentamycin + ampicillin
 * If CrCl 75: ceftriaxone 1 gram IV q 24
 * If suspect pseudomonas: tobramycin 3mg/kg IV q24 hours  or  ceftazadine 1-2gram IV q8 hours  or  cipro
 * Duration: 7 days if prompt response, 10 days if delayed
 * Tailor antibiotics to susceptability results. Switch from IV to PO when hemodynamically stable, improving clinically, able to tolerate PO, normal functioning GI tract

Asymptomatic Bacterirua in Pregnancy

 * Screen at first prenatal visit.
 * Amoxicillin 500mg PO TID x 3-7 days. Other options: nitrofurantoin, TMP/SMX as long as no contraindications.
 * Nitrofurantoin contraindicated in term pregnant woman (>36 weeks), labor, neonates due to risk of hemolytic anemia
 * TMP/SMX is contraindicated in first trimester- risk of folate deficiency/NTD, and during last 6 weeks of pregnancy due to risk of kernicterus
 * Perform follow-up culture and retreat if necessary

Acute Cystitis in Pregnancy

 * Do follow-up culture to ensure resolution
 * Cephalexin 500mg PO TID-QID x 7 days
 * Other options: amoxicillin x 7days, nitrofurantoin x 5 days, fosfomycin x 1 dose, TMP/SMX x 3 days as long as no contraindications

Pyelonephritis in Pregnancy

 * Ceftriaxone IV

Early Recurrence <1 month:

 * re-treat x 7-14 days. Repeat culture.
 * Options: TMP/SMX, nitrofurantoin

Prophylaxis

 * 2 or more episodes in 6 months or > 3 episodes/year
 * First line:
 * TMP/SMX 1 tab or 1/2DS tab qhs 3x weekly or post-coital
 * Trimethoprim 100mg PO qhs or post-coital
 * Nitrofurantoin 50mg or 100mg qhs or post-coital
 * Second line:
 * Cephalexin 125-250mg qhs or post-coital
 * Norfloxacin 200mg PO every other day or 3x per week or post-coital
 * Fosfomycin 3 grams dissolved in 1/2 cup cold water q 10days

Children
First line Second line Third line Inpatient: IV amp/gent or ceftriaxone/cefotaxime
 * TMP/SMX 5-10mg/kg/day divided q12 hours
 * Nitrofurantoin 5-7mg/kg/day divided q6hours (DO NOT USE IN < 1 month old)
 * Amoxicillin 40mg/kg/day divided q8 hours (high rate of resistance therefore need longer course)
 * Cephalexin 25-50mg/kg/day divided q6hours
 * Cefixime 8mg/kg/day divided q12-24 hours
 * Amox/clav 40mg/kg/day divided BID
 * <2 months 5-7 days of IV treatment then PO x total 10-14
 * PO cefixime
 * Fluroquinolones are contraindicated in children < 12 years of age

Prevention

 * Regular voiding patterns
 * Good hygiene practices
 * Remove catheter whenever it is contraindicated
 * Proper catheter maintenance practice (e.g. sterile insertion)

Complications

 * sepsis
 * pyelonephritis
 * impacted infected stones
 * acute kidney injury

Differential

 * See dysuria page
 * STIs, vaginitis, renal stones, interstitial cystitis, prostatitis

Resources
TOH guidelines for treatment of UTI

Anti-infective Guidelines for Community Acquired Infections 2013