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Urinary Tract Infections, Adult, Emergency Medicine

Basics

Description

- Colonization of urine with uropathogens and invasion of genitourinary (GU) tract - Defined as urinary symptoms with ≥102 to 105 CFU/mL of uropathogen and ≥10 WBC/mm3 - Lifetime risk of UTI in women is >50% - Uncomplicated cystitis: - Females aged 13 " 50 - Symptoms <2 " 3 days - Not pregnant - Afebrile (temperature <38 °C) - No flank pain - No costovertebral angle tenderness (CVAT) - Fewer than 4 UTIs in past year - No recent instrumentation or previous GU surgery - No functional/structural GU abnormality - Not immunocompromised - Neurologically intact

- Complicated pyelonephritis: - Renal parenchymal infection - Temperature >40 °C - Urosepsis with septic shock - Intractable nausea, vomiting - Diabetes, other immunosuppression - Pregnancy (especially latter half) - Concomitant obstruction or stone - Asymptomatic (occult)

- Risk factors: - Population: - Newborn, prepubertal girls, young boys - Sexually active young woman - Postmenopausal woman, elderly males

- Lower tract infection: Cystitis: - Dysuria, frequency, urgency, hesitancy - Suprapubic pain - Hematuria

- Antibiotics of choice: - Nitrofurantoin - TMP/SMX - Fluoroquinolones 2nd-line treatment in women: - Sulfonamide intolerance - All quinolones equally effective ( ¢ ¼95% susceptibility rates) but side effects vary - High frequency of antimicrobial resistance related to recent treatment - Live in areas with unknown or >20% resistance to TMP/SMX

- Treatment of upper tract disease " rule of 2s: - 2 L of IV crystalloid - 2 tablets of oxycodone/acetaminophen - 2 g of ceftriaxone or 2 mg/kg of gentamicin - If fever drops by 2 °C and patient can retain 2 glasses of water - Discharge with fluoroquinolone for 2 wk. - Follow up in 2 days.

- Treat asymptomatic bacteriuria in pregnancy with 4 " 7-day course of antibiotics: - Nitrofurantoin: - May cause birth defects if used in 1st trimester - Contraindicated in G6PD-deficiency

- Quinolones should be avoided: - CNS reactions - Blood dyscrasias - Effects on collagen formation

- Inability to comply with oral therapy - Toxic appearing, unstable vital signs - Pyelonephritis: - Intractable symptoms - Extremes of age - Immunosuppression - Urinary obstruction - Consider if coexisting urolithiasis - Significant comorbid disease - Outpatient treatment failure - Late in pregnancy

  • Colonization of urine with uropathogens and invasion of genitourinary (GU) tract
  • Defined as urinary symptoms with ≥102 to 105 CFU/mL of uropathogen and ≥10 WBC/mm3
  • Lifetime risk of UTI in women is >50%
  • Uncomplicated cystitis:Females aged 13 " 50Symptoms <2 " 3 daysNot pregnantAfebrile (temperature <38 °C)No flank painNo costovertebral angle tenderness (CVAT)Fewer than 4 UTIs in past yearNo recent instrumentation or previous GU surgeryNo functional/structural GU abnormalityNot immunocompromisedNeurologically intact
  • Complicated cystitis:Do not meet above criteriaMale genderPatients with anatomic, functional, or metabolic abnormalities of GU tractPostvoid residual urineCathetersResistant pathogensRecent antimicrobial use
  • Uncomplicated pyelonephritis:Renal parenchymal infectionDysuria, frequency, urgencyFever, chills, myalgias, nausea, vomitingFlank, back, or abdominal painCVA tendernessLeukocytosis (common)
  • Complicated pyelonephritis:Renal parenchymal infectionTemperature >40 °CUrosepsis with septic shockIntractable nausea, vomitingDiabetes, other immunosuppressionPregnancy (especially latter half)Concomitant obstruction or stoneAsymptomatic (occult)

Etiology

  • Mechanism:Organisms colonize periurethral area and subsequently infect the GU tract.
  • Risk factors:Population:Newborn, prepubertal girls, young boysSexually active young womanPostmenopausal woman, elderly malesBehavior:Sexual intercourse, spermicides, diaphragms
  • Elderly females/postmenopausal state
  • Less efficient bladder emptying, bladder prolapse, alteration of bladder defenses
  • Increased vaginal pH
  • Contamination due to urinary or fecal incontinence (Enterobacteriaceae)
  • Instrumentation:Elderly males due to prostatic hypertrophy and instrumentation
  • Organisms:Escherichia coli (80 " 85%)Staphylococcus saprophyticus (10%)Other (10%): Klebsiella, Proteus mirabilis, Enterobacter spp., Pseudomonas aeruginosa, group D streptococci

Diagnosis

Signs and Symptoms

  • Lower tract infection: Cystitis:Dysuria, frequency, urgency, hesitancySuprapubic painHematuria
  • Upper tract infection: Pyelonephritis:Symptoms of cystitis:Fever, chillsFlank pain and/or tendernessNausea, vomiting, anorexiaLeukocytosisUp to 50% of patients with cystitis may actually have pyelonephritis:Symptom duration >5 days, homelessness, and recent UTI are risk factors for upper tract infectionElderly or frail patients:Altered mental statusAnorexiaDecreased social interactionAbdominal painNocturia, incontinenceSyncope or dizziness

Essential Workup

  • Urinalysis (dipstick test, microscopy)
  • Females: Rule out pregnancy, urethritis, vaginitis, pelvic inflammatory disease (PID)
  • Males: Rule out urethritis, epididymitis, prostatitis; inquire about anal intercourse/HIV.
  • Urologic evaluation in young healthy males with 1st UTI is not routinely recommended.

Diagnosis Tests & Interpretation

Lab

  • Rapid Urine Screen:Dipstick (leukocyte esterase + nitrite) most effective when urine contains 105 CFU/mLLab specimen unnecessary if pyuria and bacteriuria confirmed by dipstickLeukocyte esterase: Positive likelihood ratio (LR+) ¢ ¼5, negative likelihood ratio (LR ¢ ) ¢ ¼0.3Nitrite: LR+ ¢ ¼30, LR ¢ ¢ ¼0.5
  • Urinalysis/microscopy:Obtain if rapid urine screen is unavailable or negative in patients with presumed UTI.10 WBC/mm3 in clean catch midstream urine indicates infection.Bacteria detected in unspun urine indicates >105 CFU/mL. (LR+ ¢ ¼20, LR ¢ ¢ ¼0.1)
  • Indications for urine culture:Complicated UTIsNegative rapid urine screen or microscopy in patients with presumed UTIPersistent signs and symptoms after 2 " 3 days of treatmentRecurrence (relapse vs. reinfection)Recently hospitalized patientsNosocomial infectionsPyelonephritis
  • Asymptomatic bacteriuria (including positive cultures) occurs in 20% of women >65 yr, 50% of women >80 yr and generally should not be treated.
  • Consider treating symptomatic geriatric patients for 5 " 10 days to decrease risk of recurrent or persistent bacteriuria.
  • Fluoroquinolones may cause CNS side effects.

Imaging

  • Indicated for complicated upper tract disease (see Pyelonephritis)
  • Helical CT, renal ultrasound, or IV pyelogram if concomitant stone or obstruction suspected

Diagnostic Procedures/Surgery

Patients with significant hematuria, recurrent UTI with same uropathogen, or symptoms of obstruction need urologic evaluation to identify structural or functional abnormality.

Differential Diagnosis

  • Appendicitis
  • Diverticulitis
  • Epididymitis
  • Nephrolithiasis
  • PID/cervicitis
  • Prostatitis
  • Pyelonephritis
  • Urethritis
  • Vulvovaginitis

Treatment

Initial Stabilization/Therapy

Urosepsis/septic shock:

  • Manage airway and resuscitate as indicated
  • IV crystalloid and vasopressors as needed
  • Early goal-directed therapy

Ed Treatment/Procedures

Stable Patients

  • For uncomplicated UTIs in women for most antibiotics, 3 days of therapy:More effective than single doseClinically as effective as 5 " 10-day course with fewer side effects
  • Resistance varies by place and changes over time:In North America, 40 " 50% of E. coli are resistant to ampicillin; 3 " 17% to fluoroquinolones and is increasing.Resistance to trimethoprim " sulfamethoxazole (TMP/SMX) is increasing (up to 30%).Nitrofurantoin: In some studies, nitrofurantoin resistance is less than for other more widely used antibiotics.Culture resistance may not correlate with clinical effect because urine antibiotic concentrations are much higher than those used in laboratory testing. However, symptom resolution may be delayed a few days in patients with resistant bacteria.
  • Antibiotics of choice:NitrofurantoinTMP/SMXFluoroquinolones 2nd-line treatment in women:Sulfonamide intoleranceAll quinolones equally effective ( ¢ ¼95% susceptibility rates) but side effects varyHigh frequency of antimicrobial resistance related to recent treatmentLive in areas with unknown or >20% resistance to TMP/SMXOral cephalosporins may be reasonable alternatives in specific circumstances:Require 7-day treatment regimensAmoxicillin " clavulanate not as effective as ciprofloxacin, probably due to failure to eradicate vaginal E. coliDiabetic women have increased risk of bacteriuria with Klebsiella spp.Treat dysuria with phenazopyridine.Treat pain with appropriate analgesics.
  • Cranberry juice or tablets/products:Prevents specific E. coli from adhering to uroepithelial cells but probably does not lower UTI recurrence rate in women with history of recurrent UTIsEvidence suggests ineffective for treatment
  • Treatment of upper tract disease " rule of 2s:2 L of IV crystalloid2 tablets of oxycodone/acetaminophen2 g of ceftriaxone or 2 mg/kg of gentamicinIf fever drops by 2 °C and patient can retain 2 glasses of waterDischarge with fluoroquinolone for 2 wk.Follow up in 2 days.
  • Treat asymptomatic bacteriuria in pregnancy with 4 " 7-day course of antibiotics:Nitrofurantoin:May cause birth defects if used in 1st trimesterContraindicated in G6PD-deficiencyAmoxicillin (not 1st-line treatment due to high rate of resistance)Fosfomycin (safe and effective)TMP/SMX:SMX should be avoided late in pregnancy as kernicterus can result.TMP should be avoided in 1st trimester (folic acid antagonist; possible birth defects).Quinolones should be avoided:CNS reactionsBlood dyscrasiasEffects on collagen formation

Medication

  • Amoxicillin: 500 or 875 mg PO q12h
  • Cefixime: 400 mg PO q24h
  • Cefpodoxime: 400 mg PO q12h
  • Ceftazidime: 1 " 2 g IV q8 " 12h
  • Ceftriaxone: 1 " 2 g IV/IM q24h
  • Cefuroxime: 250 " 500 mg PO q12h
  • Cephalexin: 250 " 500 mg PO q6h
  • Ciprofloxacin: 100 " 500 mg PO q12h
  • Doripenem: 500 mg IV q8h
  • Fosfomycin: 3 g single dose
  • Gentamicin: 2 mg/kg IV or IM q8h
  • Levofloxacin: 250 mg PO q24h
  • Nitrofurantoin macrocrystals 100 mg PO q12h
  • Norfloxacin: 400 mg PO q12
  • Ofloxacin: 200 mg PO q12h or 400 mg IV q12h
  • Phenazopyridine: 200 mg PO TID for 2 days:For symptomatic treatment of dysuriaMay turn urine and contact lenses orange
  • TMP/SMX: 160 mg/800 mg PO q12h or 10 mg/kg/d IV div. q6 " 8 " 12h

Follow-Up

Disposition

Admission Criteria

  • Inability to comply with oral therapy
  • Toxic appearing, unstable vital signs
  • Pyelonephritis:Intractable symptomsExtremes of ageImmunosuppressionUrinary obstructionConsider if coexisting urolithiasisSignificant comorbid diseaseOutpatient treatment failureLate in pregnancy

Discharge Criteria

  • Well appearing, normal vital signs
  • Can comply with oral therapy
  • No significant comorbid disease
  • Adequate follow-up (48 " 72 hr) as needed
  • Healthy patients with uncomplicated pyelonephritis who respond to treatment in ED according to rule of 2s
  • Pyelonephritis in early pregnancy with good follow-up may be treated as outpatients

Issues for Referral

Recurrent UTIs require workup for underlying pathology.

Followup Recommendations

Follow-up for UTIs should start with primary care physician.

Pearls and Pitfalls

  • For women who have more than 2 episodes of acute cystitis in 6 mo or 3 episodes in 1 yr, consider long-term (6 " 12 mo) prophylactic antibiotics or postcoital prophylaxis
  • Pregnant women should be screened and treated for asymptomatic bacteriuria (ASB) because 20 " 40% of women with ASB progress to pyelonephritis.
  • ASB in pregnant women associated with increased risk of preterm birth, low birth weight, and perinatal mortality.
  • Treat ASB in renal transplant recipients, patients who have recently undergone a urologic procedure, and neutropenic patients.
  • Risk factors for acute cystitis in men: Increased age, uncircumsized, HIV infection (low CD4 counts), anatomic abnormalities (BPH or urethral strictures), and sexual activity (especially insertive anal intercourse).
  • 25% of male GU complaints are attributable to prostatitis. TMP/SMX or fluoroquinolones are 1st-line treatment.
  • In patients with indwelling catheters, pyuria is less strongly correlated with UTI than in patients without catheters.

Additional Reading

  • Gupta K, Hooton TM, Naber KG, et al. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Clin Infect Dis. 2011;52:e103 " e120.
  • Hooton TM. Clinical practice. Uncomplicated urinary tract infection. N Engl J Med. 2012;366(11):1028 " 1037.
  • Nicolle LE, Bradley S, Colgan R, et al. Infectious Diseases Society of America guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults. Clin Infect Dis. 2005;40:643 " 654.
  • St. John A, Boyd JC, Lowes AJ, et al. The use of urinary dipstick tests to exclude urinary tract infection. Am J Clin Pathol. 2006;126:428 " 436.

See Also (Topic, Algorithm, Electronic Media Element)

  • Pyelonephritis
  • UTI, Pediatric

Codes

ICD9

  • 590.80 Pyelonephritis, unspecified
  • 595.9 Cystitis, unspecified
  • 599.0 Urinary tract infection, site not specified
  • 646.60 Infections of genitourinary tract in pregnancy, unspecified as to episode of care or not applicable
  • 041.49 Other and unspecified Escherichia coli [E. coli]
  • 996.76 Other complications due to genitourinary device, implant, and graft

ICD10

  • N12 Tubulo-interstitial nephritis, not spcf as acute or chronic
  • N30.90 Cystitis, unspecified without hematuria
  • N39.0 Urinary tract infection, site not specified
  • O23.40 Unsp infection of urinary tract in pregnancy, unsp trimester
  • B96.20 Unsp Escherichia coli as the cause of diseases classd elswhr
  • N30.91 Cystitis, unspecified with hematuria
  • T83.51XA Infect/inflm reaction due to indwell urinary catheter, init

SNOMED

  • 68566005 urinary tract infectious disease (disorder)
  • 38822007 Cystitis (disorder)
  • 45816000 Pyelonephritis (disorder)
  • 307534009 Urinary tract infection in pregnancy
  • 301011002 Escherichia coli urinary tract infection (disorder)
  • 371061003 infection of bladder catheter (disorder)