Table of Contents

 

1. Abstract
2. Case Presentations
3. Introduction For Urinary Tract Infections
4. Critical Appraisal Of The Literature For Urinary Track Infections
5. Anatomy And Pathophysiology
   1. Bacteriology
   2. Physiology Of Urination
6. Differential Diagnosis For Urnary Track Infections
   1. Unclean Specimen
   2. Sterile Pyuria
   3. Noninfectious Dysuria
7. Prehospital Care For Urinary Tract Infections
8. Emergency Department Evaluation For Urinary Tract Infections
   1. Lower Versus Upper Urinary Tract Infection
   2. Complicated Versus Uncomplicated Urinary Tract Infection
   3. Recognizing Severity
   4. Physical Examination
9. Diagnostic Studies For Urinary Track Infections
   1. Laboratory Studies
      1. Basic Laboratory Tests
      2. Urine Dipstick Versus Microscopic Urinalysis
      3. Urine Culture
      4. When To Get A Urine Culture
      5. Blood Culture
      6. Testing For Sexually Transmitted Infections
   2. Imaging
      1. Intravenous Urethrogram
      2. Magnetic Resonance Imaging
   3. Ultrasound
      1. Computed Tomography
   4. Imaging Pearls
10. Treatment For Urinary Tract Infections
    1. Treatment Of Lower Urinary Tract Infection
    2. Treatment With Intravenous Fluids
    3. Pain And Nausea Control
    4. Treatment For Men
11. Special Circumstances For Urinary Tract Infections
    1. Pregnant Patients
    2. Upper Urinary Tract Infection In Pregnancy
    3. Duration Of Therapy in Pregnancy
    4. Patients With Indwelling Catheters
    5. Patients With Nephrolithiasis
    6. Patients With Diabetes Mellitus/Renal Transplant/Immunosuppression
12. Controversies And Cutting Edge For Urinary Tract Infections
    1. Antibiotic Stewardship Programs
    2. Additional Resources And Applications There are a variety of resources to help the emergency clinician.
    3. Timing Of First Dose Of Antibiotic
    4. Obtaining Cultures
13. Disposition For Urinary Tract Infections
    1. When To Admit
    2. Criteria For Safe Discharge
    3. Predischarge Checklist
    4. Follow-Up
14. Summary For Urinary Tract Infections
15. Time- and Cost-Effective Strategies For Tract Infections
16. Clinical Pathways For Antibiotics For Urinary Tract Infection In The Emergency Department
17. Risk Management Pitfalls For Urinary Tract Infection
18. Case Conclusions
19. Tables and Figures
    1. Table 1. Adult Urinary Tract Infection
    2. Table 2. Risk Factors For Complicated
    3. Table 3. Positive And Negative Predictive Values Of Urine Dipstick And Microscopic Urinalysis
    4. Table 4. Sensitivity, Specificity, And Likelihood Ratio For Urine Dipstick And Microscopic
20. References of Urinary Tract

Abstract

Urinary tract infections are a heterogeneous group of disorders, involving infection of all or part of the urinary tract, and are defined by bacteria in the urine with clinical symptoms that may be acute or chronic. Approximately 1 million urinary tract infections are treated every year in United States emergency departments. The female-to-male ratio is 6:1. Urinary tract infection s are categorized as upper versus lower tract involvement and as uncomplicated versus complicated. The emergency clinician must carefully categorize the infection and take into account patient host factors to optimally treat and disposition patients. A working knowledge of local or at least national susceptibil - ity patterns of the most likely pathogens is essential. A variety of special populations exist that require special management, including pregnant females, patients with anatomic abnormalities, and instrumented patients.

Case Presentations

It is a typical day in the ED: you finish taking sign out from your partner, sign on to the computer, and see the broad spectrum of complaints awaiting you on the tracking board. The first patient seems like a quick disposition: a 21-year-old woman with dysuria. She describes 3 days of dysuria and urgency and has mild suprapubic pain. But before you write her for antibiotics, you ask if she is having any gynecologic symptoms . . .

In the next room, you meet a pleasant 38-year-old woman, mother of 4 boys. She has had kidney stones in the past and a tubal ligation. She complains of persistent fever with a recent UTI, despite starting a second course of antibiotics. She has never complained of back pain, and currently she is afebrile. The patient looks well and her vitals are normal except for a slight tachycardia. While you say, “Let me grab our ultrasound machine, and I will be right back,” you wonder if this is just a case of antibiotic resistance or something else . . .

You sigh as you read the chief complaint on the next patient to be seen: a 45-year-old nursing home patient with weakness. He is a bed-bound patient with a history of a spinal cord injury, who has a Foley catheter. His vitals reveal a fever of 38.3°C, a pulse of 130 beats/min, and a blood pressure of 100/50 mm Hg. The nursing home note says only that he has become increasingly weak. The Foley is not well cared for; there is foul-smelling urine that is cloudy, with sediment in the collection bag. You begin your physical examination while having the nurse contact the nursing home for some more history. . .

You pick up 1 more patient, a 23-year-old woman with fever, left flank pain, and recent dysuria. She denies any previous medical problems, and she has no other complaints. Her examination is benign except for a fever of 39.2°C, pulse 110 beats/min, and slight costovertebral tenderness on the left. You start her IV, send the necessary labs, and walk back to your desk wondering if she is a simple UTI or more . . . .

Less than an hour into your shift and the theme is set: UTIs. You reflect on the broad spectrum of clinical presentations for UTIs and the accompanying challenges.

Introduction For Urinary Tract Infections

The diagnosis and management of urinary tract infection (UTI) seems, at first, like an ordinary task; however, effective management of the full spectrum of urinary tract conditions and their mimics presents a variety of challenges even for the most seasoned emergency clinician. Urinary tract symptoms are frequent presenting complaints, and knowing how to manage them properly will lower failures, bounce-backs, and complications. Knowing the atypical presentations and when to do a more extensive workup will maximize outcomes and minimize errors in management.

UTIs are divided into those involving the lower tract and those of the upper tract. Lower tract infection is confined primarily to the urinary bladder and is termed cystitis. Infection of the upper urinary tract is termed pyelonephritis, and it involves the kidneys and ureter. Pyelonephritis is characteristically more severe than cystitis, and patients with pyelonephritis frequently have systemic symptoms and appear more ill.

UTIs are also classified as uncomplicated versus complicated. This classification is not specifically anatomic or physiologic, but more generally attempts to discern which patients are most likely to recover uneventfully with therapy (uncomplicated) versus patients who are at an increased risk of treatment failure (complicated). Patient comorbidities are the primary determinants of whether a UTI is complicated versus uncomplicated.¹

The frequency and relatively benign course of most UTIs may lull the emergency clinician into the false sense that these are easy cases. While most UTIs are straightforward to diagnose, patient comorbidities, local bacterial susceptibility patterns, and available antibiotic choices and costs must be taken into account to assure an optimal outcome.

This issue of Emergency Medicine Practice takes an evidence-based approach to answering the key questions for the patient with a possible UTI:

• Is this an uncomplicated or a complicated UTI?
• What is the appropriate antibiotic to use?
• Is the patient a normal host?
• Is there an anatomic or functional abnormality?
• Is this a mimic? Could this be an abdominal aortic aneurysm or another life-threatening condition?
• Is this patient best treated as an inpatient or outpatient?
• Could the patient be septic?

Critical Appraisal Of The Literature For Urinary Track Infections

A literature search was performed on PubMed and MEDLINE® using the following terms: urinary tract infection, combined with imaging, diagnosis, treatment, emergency department management, epidemiology, and incidence of urinary tract infections. To limit the results, filters were set: journal articles, review articles, and practice guidelines. Titles, abstracts, and full articles were reviewed for content. Within the practice guidelines, primary sources of literature were reviewed. The Cochrane Database of Systematic Reviews were also referenced. Important practice guidelines reviewed include the Infectious Diseases Society of America (IDSA) publication on uncomplicated cystitis and pyelonephritis. Findings from 6 randomized controlled trials, 6 laboratory studies, 27 prospective observational studies, 15 retrospective studies, 2 meta-analyses, 2 systematic reviews, 6 guidelines, 26 reviews, 3 textbook chapters, 2 case reports, and 2 editorials are included here. The total number of patients enrolled in included prospective and retrospective studies was 1,846,871.

The literature on UTI is extensive. No particular specialty dominates the literature on UTI. The literature spans the disciplines of emergency medicine, internal medicine, family practice, obstetrics and gynecology, urology, and infectious disease. The advantages of split ownership are volume and coverage: there is a large amount of literature, and most scenarios have been addressed. The disadvantage of split ownership is the lack of authoritative, multidisciplinary studies and consensus statements that outline specific management options for clinicians. Additionally, many of the studies of antibiotics compare in vitro susceptibilities between antibiotics but do not compare clinical efficacy.

Future evidence-based clinical guidelines and research for UTIs should include:

1. Authoritative multidisciplinary consensus statements on resistance patterns and recommended empiric therapy.
2. Regional studies to establish the geography of bacterial resistance patterns and changes in resistance patterns.
3. Development and trials of new antibiotics.
4. More studies on the role of antibiotic stewardship programs.

Risk Management Pitfalls For Urinary Tract Infection

1. “Fever and tachycardia are routine with pyelonephritis, and I only need to screen for sepsis if the patient looks septic.” The definition of sepsis has recently been defined much more broadly by the Surviving Sepsis Campaign guidelines. A patient needs only to have a source of infection and 2 of 24 criteria positive to meet the current definition for the diagnosis of sepsis. Fever and tachycardia, which are frequently present in pyelonephritis, qualify the patient as having sepsis by the Surviving Sepsis Campaign guidelines. Nonetheless, in our view, the criteria for sepsis cannot be interpreted to mean that every patient who presents febrile and tachycardic must be admitted. Rather, the presence of fever and tachycardia should serve as a trigger to treat the fever and tachycardia and to consider further workup for the presence of sepsis as a definite process. IV fluids are indicated as well as treatment of the fever. Further laboratory tests (such as a complete blood count, a basic metabolic profile, and a lactate level) can be considered to see if more criteria for sepsis are present. Select patients can be safely sent home on a case-by-case basis; the first dose of parenteral antibiotics prior to discharge and mandatory follow-up in 24 hours is warranted.
2. “I don’t think about also prescribing pain and nausea medications for home.” Patients return to the ED for preventable and unpreventable reasons. Unpreventable reasons include new resistance patterns and poor response to appropriate therapy. Preventable reasons include use of an antibiotic with known high resistance in the community, poor patient compliance, and inadequate treatment of pain and nausea. The emergency clinician can reduce the preventable returns by reinforcing the need to take the full course of antibiotics, by prescribing according to local antibiotic stewardship programs and antibiograms, and by prescribing medications for pain and nausea control in addition to antibiotics at discharge.
3. “Her heart rate is still 120 beats/min, but that is just part of having a UTI. She will be fine.” A certain percentage of patients will return, even with sepsis, after being appropriately diagnosed and treated. To decrease the risk of bounceback or occult sepsis, emergency clinicians are encouraged to resolve abnormal vital signs before discharge. Pyrexia should be treated. If the tachycardia is associated with dehydration, intravenous fluids should be administered. It should be clear to anyone reviewing the chart that the practitioner searched for and reasonably ruled out the presence of clinical sepsis.
4. "He has a positive urine dipstick, so my work here is complete.” When performing a fever workup, it can be tempting to assume a diagnosis of UTI or pelvic inflammatory disease in a patient with a fever and trace or 1+ leukocytes. Particularly in the case of a patient with high fever, abnormal vital signs, or immunosuppression, it is important to consider other possibilities. The emergency clinician should also bear in mind that fever is relatively uncommon in isolated cystitis. Strategies to reduce risk include gathering history and physical examination information to rule out other causes of infection, catheterization of the urinary bladder to obtain a more reliable sample, and running a microscopic urinalysis to confirm the presence of leukocytes and rule out the presence of contamination.
5. “I didn’t know that counted as a complicated UTI.” UTIs will behave differently in different patients. It is important to consider the host patient as well. Has the patient been recently hospitalized or is the patient immunosuppressed? Does the patient have diabetes mellitus? Conditions that weaken the host should be considered.
6. “I didn’t know appendicitis could cause pyuria.” In the case of lower abdominal pain, the presence of trace or 1+ leukocytes can lead to premature closure in the evaluation of abdominal pain. Cystitis characteristically causes pain mostly with urination. Pyelonephritis characteristically presents with fever and flank pain (except in transplant patients where the tenderness will be over the graft site) and not with abdominal pain. When the inflamed appendix is close to the ureter, it can cause sterile pyuria. In patients with lower abdominal pain and trace or 1+ leukocytes on a urine dipstick, the diagnosis of appendicitis should be at least considered, and it should be clearly documented that the right lower quadrant is nontender if no more workup is to be done.
7. “She had lower abdominal pain and pyuria, so I didn't think a pelvic examination was indicated.” With pelvic inflammatory disease or tuboovarian abscess, irritation of the bladder can also cause sterile pyuria. In women, the diagnosis of pelvic inflammatory disease or tubo-ovarian abscess should always be at least considered when lower abdominal pain and mild or minimal pyuria are present. It is recommended to establish and document that there are no concurrent pelvic symptoms in women with UTI. Pelvic examination may be warranted.
8. “History and physical examination are of diminished value in the modern age.” Appendicitis, tubo-ovarian abscess, diverticulitis, nephrolithiasis, spinal epidural abscess, and pelvic inflammatory disease can mimic UTI. The key to picking these mimic cases is not so much in testing as it is in careful questioning and physical examination.
9. “I will not let antibiotic stewardship programs interfere with my practice.” Antibiotic stewardship programs and local antibiograms, when present, are a valuable resource and represent the community standard of care. Treating according to a national application or booklet (which lack local antibiogram data or antibiotic stewardship program recommendation) is a second-line choice. In our community, adherence to antibiotic stewardship program recommendations and local antibiogram data have resulted in fewer treatment failures, fewer complications (such as C difficile infection), and, somewhat surprisingly, overall diminished resistance pattern across the board. In our institutions, practitioners who do not prescribe according to antibiotic stewardship program recommendations and do not document a reason for exception are subject to peer review.
10. “I just use the most broad-spectrum antibiotic, so my treatment never fails.” It may be tempting to use the “biggest gun,” but it is not always best for the patient. Antibiotics with relatively high anaerobic bactericidal activity (such as amoxicillin clavulanate or levofloxacin) are seldom the first-line choice. By killing commensal organisms, they may increase the risk of C difficile infection. Additionally, antibiotics with extreme range but not a lot of strength in any single area (such as ciprofloxacin) are also considered second-line choices, not just because of resistance patterns, but because their weak activity against such a broad spectrum tends not to be bactericidal but to simply promote increased resistance across the board. Practice environments can be unique, and it is possible for fluoroquinolones to be firstline agents in some communities; it depends on the local antibiogram and the local antibiotic stewardship program recommendations.

Tables and Figures

References of Urinary Tract

Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.

To help the reader judge the strength of each reference, pertinent information about the study will be included in bold type following the reference, where available. In addition, the most informative references cited in this paper, as determined by the authors, will be noted by an asterisk (*) next to the number of the reference.

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