Urinary Tract Infection

Aka: Urinary Tract Infection, UTI, Bladder Infection, Acute Cystitis

II. Causes

  1. Normal Host
    1. Escherichia coli (80-86%)
    2. Staphylococcus saprophyticus (10-15% of young women, 4% overall)
      1. More aggressive and recurrent infections
      2. Associated with Pyelonephritis
    3. Klebsiella (3%)
    4. Proteus (3%)
  2. Nephrolithiasis associated infection
    1. Proteus (urease positive)
    2. Klebsiella
  3. Sexually Transmitted Diseases
    1. Chlamydia
    2. Neisseria gonorrhoeae
    3. Herpes Simplex Virus II (Genital Herpes)

III. Risk factors: Complicated Cystitis

  1. Male gender
  2. Pregnancy
  3. Hospital acquired Urinary Tract Infection
  4. Prolonged urinary tract symptoms (>1 week)
  5. Poorly controlled Diabetes Mellitus
  6. Immunocompromised
  7. Underlying urologic disorder
    1. Vesicoureteral reflux
    2. Recurrent complicated Urinary Tract Infections
    3. Catheter associated Urinary Tract Infection
    4. Neurogenic Bladder dysfunction
    5. Polycystic Kidney Disease
    6. Urologic instrumentation or stenting
    7. Status renal transplant
    8. Urinary Tract Obstruction (e.g. Nephrolithiasis)
    9. Men with Prostatitis or BPH

IV. Symptoms

  1. Most suggestive of Urinary Tract Infection
    1. Dysuria (Likelihood Ratio 2.0)
      1. If absent, Likelihood Ratio 0.5
    2. Urinary Frequency (Likelihood Ratio 1.8)
    3. Hematuria (Likelihood Ratio 1.5)
      1. Occurs in 30% of cases
  2. Other symptoms with Urinary Tract Infection
    1. Urinary Urgency
    2. Suprapubic Pain (especially after voiding)

V. Differential Diagnosis

  1. Dysuria
    1. See Dysuria
    2. See Dysuria in Children
    3. See Dysuria in Men
    4. See Dysuria in Women
  2. Urethritis
    1. Pain at onset of urination
  3. Vaginitis
    1. External Dysuria
    2. Vaginal irritation or discharge
  4. Chlamydia trachomatis
    1. Long, insidious onset
    2. Sexually active
  5. Acute Pyelonephritis
    1. Fever, Flank Pain, and Nausea or Vomiting
    2. Risk factors for cystitis with occult Pyelonephritis
      1. Women (30% have subclinical Pyelonephritis)
      2. Pregnancy
      3. Diabetes Mellitus
      4. Immunocompromised patients
      5. Urinary Tract Infection under age 12 years
      6. Genitourinary comorbid condition
  6. Acute Urethral syndrome (Sterile or low urine Bacterial count)
    1. Gonorrhea
    2. Chlamydia
    3. Herpes Simplex Virus
    4. Vaginitis
  7. Sterile Pyuria
    1. Chlamydia (most common)
    2. Genitourinary Tuberculosis (classic sterile pyuria)
  8. Asymptomatic Bacteriuria (organisms isolated on Urine Culture, but often not responsible for cystitis)
    1. Enterococcus
    2. Streptococcus Agalactiae (Group B Streptococcus)
    3. Hooton (2013) N Engl J Med 369(20):1883-91 [PubMed]

VI. Labs

  1. Urinalysis
    1. Urine Leukocyte Esterase (high Test Sensitivity but low Test Specificity)
    2. Urine Nitrite (high Test Specificity, but low Test Sensitivity)
    3. Urine White Blood Cells on microscopy
  2. Urine Culture
    1. Not needed in uncomplicated UTI (young, healthy non-pregnant women)
    2. Recommended in complicated UTI or suspected Pyelonephritis
    3. Positive for >100k organisms
    4. Women with Dysuria have <100k organisms in 30% cases

VII. Diagnosis: Factors suggestive of complicated UTI

  1. Extremes of age (preadolescent, or post-Menopause)
  2. Chronic renal disease
  3. Diabetes Mellitus
  4. Immunodeficiency
  5. Pregnancy
  6. Recent Urinary Tract Instrumentation
    1. Ureteral Stents
    2. Indwelling catheters
  7. Urologic abnormalities
    1. Nephrolithiasis
    2. Neurogenic Bladder
    3. Polycystic Kidney Disease

VIII. Diagnosis: Prediction Rule

  1. Criteria
    1. New onset frequency and Dysuria
    2. Absent Vaginal Discharge and irritation
  2. Efficacy
    1. Pretest probability of UTI based on symptoms: 90%
    2. Probablity of UTI with negative Urinalysis: 23%
    3. Positive Predictive Value: 90%
  3. Interpretation
    1. May be treated without Urinalysis and Urine Culture
    2. Editorial note: I do not recommended this (other Dysuria causes, Antibiotic Overuse)
      1. Alternative: Even dipstick testing alone is reasonably accurate, priced and fast
  4. Reference
    1. Bent (2002) JAMA 287:2701-10 [PubMed]

IX. Diagnosis: Findings suggestive of upper Urinary Tract Infection (Pyelonephritis)

  1. See Pyelonephritis
  2. Fever, chills
  3. Flank Pain
  4. Vomiting
  5. Pregnancy (second and third trimester are higher risk)
  6. Underlying urinary tract disorder
  7. History of Ureteral Stenting or other instrumentation
  8. Male patients
  9. Insulin Dependent Diabetes Mellitus
  10. HIV Infection
  11. Immunosuppressants (Chronic Corticosteroid use, status-post transplant)
  12. Extremes of age (very young or very old)
    1. Underwhelming presentations of upper tract disease

X. Precautions

  1. Consider Sexually Transmitted Infection in Vaginitis or male Dysuria
  2. Consider Nephrolithiasis with Urinary Tract Infection (emergency) when Flank Pain is severe
  3. Empiric antibiotic regimens should be based on local resistance rates
  4. Urine Culture is not needed in occasional, uncomplicated Urinary Tract Infection (young, healthy, non-pregnant women)
  5. Assume upper tract disease in findings listed above
    1. Adjust management strategy to treat upper tract (e.g. avoid Macrobid or Nitrofurantoin)

XI. Management: General

  1. General measures in women
    1. Women should clean perineum wiping front to back
    2. Women should empty Bladder before, after intercourse
    3. Avoid Contraceptive Diaphragm
  2. Antibiotics
    1. Course: Anticipate symptom relief within 36 hours of starting antibiotics
    2. Antibiotic duration
      1. Uncomplicated treatment: 3 days (except noted)
        1. Nitrofurantoin and Macrobid course is 5 days (was 7 days)
      2. Complicated treatment: 10 day course
    3. Antibiotic Resistance increasing
      1. Trimethoprim Sulfamethoxazole (Septra): 18%
      2. Beta Lactams: 20%
      3. Ampicillin: 38%
      4. Nitrofurantoin resistance low (1-2%)
      5. Fluoroquinolone resistance low (2.5%)
        1. Avoid as first line agents if possible (due to other adverse effects)
        2. Consider in areas of high Septra resistance areas
    4. Cure may occur despite resistance to antibiotic used
    5. Risks for resistance
      1. Trimethoprim Sulfamethoxazole within last 3-6 months
      2. Diabetes Mellitus
      3. Recent hospitalization
      4. Travel outside United States
      5. Resistance rates in community >20%
  3. Acute Uncomplicated UTI: First-Line agents
    1. Note that Ciprofloxacin has been demoted from first-line agent due to adverse effects (see below)
    2. Trimethoprim-Sulfamethoxazole (Bactrim) DS one orally twice daily for 3 days
      1. Avoid if local resistance rate >20%
    3. Nitrofurantoin (Macrobid) one orally twice daily for 5 days
      1. Avoid if GFR <30 ml/min (risk of interstitial pulmonary fibrosis)
    4. Fosfomycin (Monurol) 3 grams for one dose
      1. Consider as a single dose in Emergency Department (e.g. patient non-compliant)
      2. More expensive and may be less effective (58% efficacy compared with 70% for Nitrofurantoin)
        1. Huttner (2018) JAMA 319(17): 781-9 +PMID:29710295 [PubMed]
  4. Acute Uncomplicated UTI with risks for resistance (prior Bactrim use or international travel in last 6 months)
    1. Nitrofurantoin
      1. Avoid if GFR <30 ml/min (risk of interstitial pulmonary fibrosis)
      2. Nitrofurantoin 100 mg orally four times daily for 5 days
      3. Macrobid 100 mg orally twice daily for 5 days
        1. Five days is sufficient course (previously used for 7 days)
        2. Gupta (2007) Arch Intern Med 167(20):2207-12 [PubMed]
    2. Fosfomycin (Monurol) 3 grams for one dose
    3. Also see Fluoroquinolones below
  5. More severe disease or resistant UTI organisms: Fluoroquinolones
    1. Precautions regarding Fluoroquinolones
      1. Risk of Tendinopathy (and Achilles Tendon Rupture) and Peripheral Neuropathy
      2. Avoid if local resistance rate >10%
      3. Renal dose adjustment required if GFR reduced
      4. Although 3 day courses are listed, complicated UTI is treated for 10 days (up to 6 weeks in men)
    2. Ciprofloxacin 250 mg PO bid for 3 days
      1. In healthy older women, 3 days equivalent to 7 days
      2. Vogel (2004) CMAJ 170:469-73 [PubMed]
    3. Levofloxacin 250 mg every 24 hours for 3 days
    4. Norfloxacin 400 mg PO bid for 3 days
    5. Ofloxacin 200 mg PO bid for 3 days
    6. Avoid Moxifloxacin and gemifloxacin (poor penetration into urine)
  6. Antibiotics for UTI in Pregnancy
    1. See Urinary Tract Infection in Pregnancy
  7. Other antibiotics used in Urinary Tract Infection
    1. Precautions
      1. Beta lactams have lower efficacy in UTI
    2. Cephalexin (Keflex) 500 mg orally twice daily for 5-7 days
    3. Amoxicillin-Clavulanate (Augmentin) 875 mg orally twice daily for 5-7 days
    4. Cefdinir 300 mg orally twice daily for 3-7 days
  8. Sexually active young patients
    1. Avoid Nitrofurantoin (Macrobid)
      1. Staphylococcus saprophyticus resistance
    2. Consider Chlamydia sceening
    3. Consider other Sexually Transmitted Disease Testing

XII. Management: Special Circumstances

  1. See Recurrent Urinary Tract Infection
  2. See Ureteral Stent
  3. ESBL (Extended Spectrum Beta-Lactamase) producing E Coli and Klebsiella
    1. Fosfomycin (cystitis)
    2. Ertapenem

XIII. Management: Asymptomatic Bacteriuria

  1. See Asymptomatic Bacteriuria

XIV. Complications: Surgical

  1. Perinephric Abscess
    1. Urinary Tract Infection contiguous spread
    2. Contrast with renal abscess (hematogenous spread)
  2. Emphysematous Pyelonephritis
    1. Seen in Diabetes Mellitus
    2. Requires surgical drainage (otherwise high mortality)

XV. References

  1. (2019) Sanford Guide, accessed on IOS 9/21/2019
  2. Colgan (2011) Am Fam Physician 84(7): 771-6 [PubMed]
  3. Ebell (2006) Am Fam Physician 73:293-6 [PubMed]
  4. Gupta (1999) JAMA 281:736-8 [PubMed]
  5. Gupta (2012) Ann Intern Med 156(5): ITC3-1 [PubMed]
  6. Hooton (1997) Infect Dis Clin North Am 11:551-81 [PubMed]
  7. Michels (2015) Am Fam Physician 92(9): 778-86 [PubMed]

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Related Studies

Ontology: Urinary tract infection (C0042029)

Definition (MSHCZE) Zánětlivé reakce epitelu močového ústrojí na mikrobiální invazi. Časté jsou bakteriální infekce spojené s BAKTERIURIÍ a PYURIÍ.
Definition (MEDLINEPLUS)

The urinary system is the body's drainage system for removing wastes and extra water. It includes two kidneys, two ureters, a bladder, and a urethra. Urinary tract infections (UTIs) are the second most common type of infection in the body.

You may have a UTI if you notice

  • Pain or burning when you urinate
  • Fever, tiredness or shakiness
  • An urge to urinate often
  • Pressure in your lower belly
  • Urine that smells bad or looks cloudy or reddish
  • Pain in your back or side below the ribs

People of any age or sex can get UTIs. But about four times as many women get UTIs as men. You're also at higher risk if you have diabetes, need a tube to drain your bladder, or have a spinal cord injury.

If you think you have a UTI it is important to see your doctor. Your doctor can tell if you have a UTI with a urine test. Treatment is with antibiotics.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases
Definition (NCI) A bacterial infectious process affecting any part of the urinary tract, most commonly the bladder and the urethra. Symptoms include urinary urgency and frequency, burning sensation during urination, lower abdominal discomfort, and cloudy urine.
Definition (NCI_CTCAE) A disorder characterized by an infectious process involving the urinary tract, most commonly the bladder and the urethra.
Definition (CSP) infections affecting stuctures participating in the secretion and elimination of urine: the kidneys, ureters, urinary bladder and urethra.
Definition (MSH) Inflammatory responses of the epithelium of the URINARY TRACT to microbial invasions. They are often bacterial infections with associated BACTERIURIA and PYURIA.
Concepts Disease or Syndrome (T047)
MSH D014552
ICD9 599.0
ICD10 N39.0
SnomedCT 155897002, 197930008, 266635000, 266634001, 155896006, 197924008, 274110008, 68566005
LNC LA6437-3
English Urinary tract infection, Infection, Urinary Tract, Infections, Urinary Tract, Tract Infection, Urinary, Tract Infections, Urinary, Urinary Tract Infections, Urinary tract infection, site not specified, UTI, Urinary tract infections, Infection of urinary tract, Urinary tract infect.unsp.NOS, Urinary tract infection, site not specified NOS, URINARY TRACT INFECT, Urinary infection NOS, urinary tract infection (diagnosis), urinary tract infection, uti, Infection urinary tract, Urinary tract infection NOS, Urinary infection, Urin tract infection NOS, Urinary Tract Infections [Disease/Finding], urinary tract infection (UTI), utis, urinary tract infections, urinary infection, Urinary Tract Infection, Urinary tract infection, site not specified NOS (disorder), Infection - urinary NOS, Urinary tract infection (& [NOS]) (disorder), Urinary tract infection (& [NOS]), Urinary infection NOS (disorder), INFECTION, URINARY TRACT, Urinary Tract Infectious Disease, TRACT, INFECTION OF URINARY, URINARY TRACT INFECTION, Urinary tract infectious disease, UTI - Urinary tract infection, Urinary tract infectious disease (disorder), infected; urinary, infection; urinary tract, urinary; infection, urine; infected, Urinary tract infection, NOS, Urinary tract infectious disease, NOS, Urinary tract infection; site not specified
Italian Infezione delle vie urinarie, Infezione urinaria, Infezione delle vie urinarie NAS, Infezione delle vie urinarie, sito non specificato, Infezioni delle vie urinarie
Dutch urinaire infectie, urineweginfectie, op niet-gespecificeerde plaats, urineweginfectie NAO, infectie van de urinewegen, geïnfecteerd; urine, infectie; urinewegen, urine; geïnfecteerd, urine; infectie, Urineweginfectie, lokalisatie niet gespecificeerd, urineweginfecties, urineweginfectie, Infectie, urineweg-, Urineweginfectie
French Infection des voies urinaires SAI, IVU, Infection urinaire, Infection des voies urinaires, site non précisé, Infection des voie urinaires, INFECTION DE L'APPAREIL URINAIRE, Infection du tractus urinaire, Infections des voies urinaires, Infections urinaires
German Infektion der Harnwege, Harnwegsinfektion NNB, Harnwegsinfektion, Stelle nicht bekannt, UTI, HARNWEGSINFEKT, Harnwegsinfektion, Lokalisation nicht naeher bezeichnet, Harnwegsinfektion, Harnwegsinfektionen
Portuguese Infecção das vias urinárias, Infecção das vias urinárias NE, Infecção das vias urinárias de localização NE, Infecção urinária, INFECCAO DO TRACTO URINARIO, Infecções do Sistema Urinário, Infecção do tracto urinário, Infecções das vias urinárias, Infecções Urinárias
Spanish Infección del tracto urinario, localización no especificada, Infección urinaria, Infección del tracto urinario NEOM, ITU, INFECCION VIAS URINARIAS, infección urinaria, SAI, infección urinaria, SAI (trastorno), infección de la vía urinaria, localización no especificada, SAI, infección de la vía urinaria, localización no especificada, SAI (trastorno), enfermedad infecciosa de las vías urinarias, infección de las vías urinarias, infección urinaria (trastorno), infección urinaria, Infecciones del tracto urinario, Infección del tracto urinario, Infecciones Urinarias
Japanese 尿路感染, 尿路感染ＮＯＳ, 尿路感染、部位不明, ﾆｮｳﾛｶﾝｾﾝ, ﾆｮｳﾛｶﾝｾﾝNOS, ﾆｮｳﾛｶﾝｾﾝﾌﾞｲﾌﾒｲ
Swedish Urinvägsinfektioner
Czech močové cesty - infekce, Infekce močových cest, blíže neurčené části, Infekční onemocnění močových cest, Infekce močových cest, Močová infekce, Infekce močových cest NOS, infekce močového ústrojí, močové ústrojí - infekce, močové infekce
Finnish Virtsatieinfektiot
Russian MOCHEVYKH PUTEI INFEKTSII, МОЧЕВЫХ ПУТЕЙ ИНФЕКЦИИ
Korean 부위가 명시되지 않은 요로 감염
Croatian URINARNE INFEKCIJE
Hungarian Fertőzés, húgyúti, Húgyúti fertőzések, húgyúti fertőzés, Húgyúti fertőzés, húgyúti fertőzés k.m.n., húgyúti fertőzés, hely nem meghatározott, UTI
Polish Zakażenie układu moczowego, Infekcja dróg moczowych, Zakażenia dróg moczowych, Infekcje dróg moczowych
Norwegian Urinveisinfeksjoner
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Acute cystitis (C0149523)

Definition (NCI) An acute infection of the bladder. It is usually caused by bacteria. Signs and symptoms include increased frequency of urination, pain or burning during urination, fever, cloudy or bloody urine, and suprapubic pain.
Concepts Disease or Syndrome (T047)
ICD9 595.0
ICD10 N30.0
SnomedCT 197833009, 155883005, 266628008, 68226007
Dutch cystitis acuut, cystitis acuut NAO, acute cystitis, acuut; cystitis, cystitis; acuut, Acute cystitis
French Cystite aiguë, Cystite aiguë SAI
German akute Zystitis, Zystitis akut NNB, Akute Zystitis
Italian Cistite acuta, Cistite acuta NAS
Portuguese Cistite aguda, Cistite aguda NE
Spanish Cistitis aguda, Cistitis aguda NEOM, cistitis aguda (trastorno), cistitis aguda
Japanese 急性膀胱炎ＮＯＳ, 急性膀胱炎, ｷｭｳｾｲﾎﾞｳｺｳｴﾝ, ｷｭｳｾｲﾎﾞｳｺｳｴﾝNOS
English acute cystitis (diagnosis), acute cystitis, Cystitis acute, Cystitis acute NOS, Cystitis;acute, cystitis acute, Acute cystitis, Acute cystitis (disorder), cystitis; acute, acute; cystitis, Acute Cystitis
Czech Akutní cystitida NOS, Akutní cystitida
Korean 급성 방광염
Hungarian Cystitis, acut k.m.n., cystitis acuta, Cystitis, acut
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Infective cystitis (C0600041)

Definition (NCI) An infectious process affecting the urinary bladder.
Definition (NCI_CTCAE) A disorder characterized by an infectious process involving the bladder.
Concepts Disease or Syndrome (T047)
SnomedCT 236620008
English BLADDER INFECTION, Infective cystitis, Bladder infection, Bladder infection NOS, Infection bladder, Infectious Cystitis, Infection;bladder, bladder infection, infection of bladder, bladder infections, Bladder Infections, Infections, Bladder, Infective cystitis (diagnosis), cystitis infective, Infection of bladder, Infective cystitis (disorder), bladder; infection, infection; bladder
Dutch blaasinfectie NAO, infectie blaas, blaasinfectie, blaas; infectie, infectie; blaas
French Infection de la vessie, Infection de la vessie SAI, INFECTION VESICALE
German Blaseninfektion, Blaseninfektion NNB, Infektion der Blase, BLASENINFEKTION
Italian Infezione vescicale, Infezione vescicale NAS, Infezione della vescica
Portuguese Infecção da bexiga, Infecção da bexiga NE, INFECCAO VESICAL
Spanish Infección de vejiga, Infección vesical, Infección vesical NEOM, INFECCION VEJIGA URINARIA, cistitis infecciosa (trastorno), cistitis infecciosa, infección de la vejiga
Japanese 膀胱感染, 膀胱感染ＮＯＳ, ﾎﾞｳｺｳｶﾝｾﾝ, ﾎﾞｳｺｳｶﾝｾﾝNOS
Czech Infekce močového měchýře, Infekce močového měchýře NOS
Hungarian húgyhólyagfertőzés, húgyhólyagfertőzés k.m.n., Fertőzés húgyhólyag
Derived from the NIH UMLS (Unified Medical Language System)

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