Evidence-Based Guidelines For Evaluation And Antimicrobial Therapy For Common Emergency Department Infections
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Evidence-Based Guidelines For Evaluation And Antimicrobial Therapy For Common Emergency Department Infections

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Table of Contents
Table of Contents
  1. Abstract
  2. Case Presentations
  3. Introduction
  4. Critical Appraisal Of The Literature
  5. Abbreviations And Acronyms
  6. Epidemiology
  7. Pharmacology Of Antibiotics
  8. Pneumonia
    1. Initial Emergency Department Evaluation And Management For Pneumonia
    2. Diagnostic Studies For Pneumonia
    3. Blood And Sputum Cultures For Pneumonia
    4. Site-Of-Care Decisions For Pneumonia
    5. Empiric Antimicrobial Therapy For Community-Acquired Pneumonia
  9. Urinary Tract Infection
    1. Initial Emergency Department Evaluation And Management For Urinary Tract Infection
    2. Diagnostic Studies For Urinary Tract Infection
    3. Cultures For Urinary Tract Infection
    4. Site-Of-Care Decisions For Urinary Tract Infections
    5. Empiric Antimicrobial Therapy For Urinary Tract Infection
      1. Acute Uncomplicated Cystitis
      2. Pyelonephritis
    6. Complicated Urinary Tract Infection
    7. Urinary Tract Infection In Pregnancy
  10. Intra-Abdominal Infection
    1. Initial Emergency Department Evaluation And Management Of Intra-Abdominal Infection
    2. Diagnostic Studies For Intra-Abdominal Infection
    3. Cultures For Intra-Abdominal Infection
  11. Skin And Soft-Tissue Infection
    1. Emergency Department Evaluation For Skin And Soft-Tissue Infection
    2. Diagnostic Studies For Skin And Soft-Tissue Infection
    3. Cultures For Skin And Soft-Tissue Infection
  12. Summary
  13. Risk Management Pitfalls For Antibiotics In The Emergency Department
  14. Case Conclusions
  15. Clinical Pathway For Treatment Of Pneumonia
  16. Clinical Pathway For Treatment Of Cystitis And Pyelonephritis
  17. Clinical Pathway For Treatment Of Complicated Intra-Abdominal Infection
  18. Clinical Pathway For Treatment Of Skin And Soft-Tissue Infections
  19. Tables and Figures
    1. Table 1. Infectious Diseases Society Of America-US Public Health Service Grading System For Rating Recommendations In Clinical Guidelines
    2. Table 2. Spectrum Of Activity Of Commonly Used Antibiotics
    3. Table 3. Antibiotics That Require Dosage Adjustments In Liver Or Kidney Disease
    4. Table 4. Common Antibiotic Regimens For Outpatient Treatment Of Community-Acquired Pneumonia
    5. Table 5. Common Antibiotic Regimens For Inpatient Treatment Of Community-Acquired Pneumonia
    6. Table 6. Common Antibiotic Regimens For Treatment Of Healthcare-Associated Pneumonia
    7. Table 7. Common Antibiotic Regimens For Uncomplicated Urinary Tract Infection
    8. Table 8. Common Antibiotic Regimens For Complicated Urinary Tract Infection
    9. Table 9. Common Antibiotic Regimens For Inpatient Treatment Of Pyelonephritis During Pregnancy
    10. Table 10. Common Antibiotic Regimens For Urinary Tract Infection During Pregnancy
    11. Table 11. Common Antibiotic Regimens For Treatment Of Community-Acquired Complicated Intra-Abdominal Infection
    12. Table 12. Common Antibiotic Regimens For Treatment Of Hospital-Acquired Complicated Intra-Abdominal Infection
    13. Table 13. Common Antibiotic Regimens For Outpatient Treatment Of Skin And Soft-Tissue Infections
    14. Table 14. Common Antibiotic Regimens For Inpatient Treatment Of Skin And Soft-Tissue Infections
    15. Table 15. Common Antibiotic Regimens For Treatment Of Necrotizing Skin And Soft-Tissue Infections
  20. References


Infections are among the most common diagnoses in the emergency department (ED), and antibiotics are among the most frequently prescribed drugs. Community-acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP) are frequently encountered in the ED, and pneumonia is the seventh leading cause of death in the United States. Cystitis, pyelonephritis, and complicated urinary tract infection (UTI) are often treated in the ED, with UTI being one of the most common reasons for healthy young women to require antimicrobial treatment. Intra-abdominal infections have an incidence of 3.5 million cases per year in the United States, and emergency clinicians must make complex decisions regarding appropriate evaluation and management. Skin and soft-tissue infections (SSTIs) are common, their incidence in the ED has been rising, and the emergence of methicillin-resistant Staphylococcus aureus (MRSA) infection has altered their management. Timely diagnosis and management of infectious disease, including proper antimicrobial treatment, is an important goal of emergency care. This issue of Emergency Medicine Practice reviews the available evidence and consensus guidelines for the management of common infectious diseases presenting to the ED and presents recommendations for treatment.

antibiotics, community-acquired, infectious, Methicillin-Resistant Staphylococcus Aureus, MRSA, community-acquired MRSA, CA-MRSA, pneumonia, community acquired pneumonia, CAP, antimicrobial, cystitis, pyelonephritis, urinary tract infection, infectious disease, skin infections, soft-tissue infections, practice guidelines, staphylococcal skin infections

Case Presentations

At 7:00 on a Monday morning, the day begins with a full line-up of “to be seen.” A 35-year-old female with no past medical history presents to the ED complaining of cough and shortness of breath for 2 days that is progressively worsening. On physical examination, she is febrile with an oxygen saturation of 94% on room air and decreased breath sounds at the right base. You order a chest x-ray that shows right lower lobe consolidation.

The second patient on your tracking board is a 70-year-old female with fever, nausea, and back pain for 3 days. She is accompanied by her daughter, who states her mother hasn’t been herself today and that she had a similar presentation when she had a UTI 2 years ago. She is febrile to 38.3°C (101°F), oriented x2, with left costovertebral angle tenderness. Her urine dipstick is positive for leukocyte esterase and nitrites.

In the next bed, you are evaluating a 23-year-old male who has had a painful, swollen right forearm for 2 days. He reports a subjective fever earlier in the evening, but no other systemic symptoms. He denies any past medical history and has no IV drug abuse and no history of diabetes. He is afebrile with normal vital signs. A 6-cm area of erythema, induration, and tenderness is noted on his proximal forearm with a 2-cm central fluctuant, raised area. He has full range of motion at the elbow.

Just as you sit down for a cup of coffee, the triage nurse notifies you that she just received an 85-year-old male from a nursing home that was sent in for evaluation for fever. He has a history of insulin-dependent diabetes mellitus, hypertension, and dementia. On physical examination, he is febrile, with otherwise normal vital signs. His abdomen is slightly distended, soft, but diffusely tender to palpation.

Four infectious disease cases in a row — it feels like an epidemic. You reflect on the challenge of choosing the right antibiotic in the age of emerging pathogens and how the right choice may be the difference between a good or bad outcome.


Clinicians who treat infectious diseases in the ED need to apply a vast amount of knowledge regarding not only which antibiotics are appropriate in a particular situation, but also the relevant microbiology, diagnostic testing, and pathophysiology of the underlying disease. Timely diagnosis and management of infectious disease, including proper antimicrobial treatment in the ED, has been shown to decrease morbidity and mortality in bacterial meningitis and sepsis1 and should be a goal of emergency care. To facilitate proper broad-spectrum coverage for initial antibiotic administration while decreasing unnecessary antibiotic use and propagating the emerging problem of multidrug-resistant organisms, evidence-based guidelines have been developed by the Infectious Diseases Society of America (IDSA) in collaboration with multiple specialty societies.

Knowledge of these guidelines and proper empiric therapy is of utmost importance to the emergency clinician when treating common and uncommon infections. Familiarity with comorbidities and risk factors for multidrug-resistant organisms and complicated infections as well as clinical decision rules to help guide diagnostic modalities, surgical consultation, and admission criteria for intravenous (IV) antibiotics may also be helpful in ensuring patients receive the best chances for proper diagnosis and appropriate treatment. This issue of Emergency Medicine Practice focuses on common infectious diseases presenting to the ED and reviews the current literature and guidelines.

Critical Appraisal Of The Literature

For this evidence-based review article, an extensive search of the PubMed database, Ovid MEDLINE®, and the Cochrane Database of Systematic Reviews was performed. A search for relevant guidelines was performed via the Agency for Healthcare Research and Quality National Guideline Clearinghouse. A thorough review of consensus guidelines and evaluation of their citations was undertaken. An online search of the IDSA website, the Centers for Disease and Control and Prevention (CDC) website, and the American College of Emergency Physicians (ACEP) website was performed.

Recommendations were formulated, to a large degree, from the available relevant guidelines of the IDSA. These include the joint recommendations for the management of pneumonia from the IDSA and the American Thoracic Society (ATS), the 2005 “Guidelines for the Management of Adults with Hospital-Acquired, Ventilator-Associated, and Healthcare-Associated Pneumonia,” and the 2007 “Community-Acquired Pneumonia in Adults: Guidelines for Management.” The authors also thoroughly reviewed the 2010 “Guidelines for the Selection of Anti-Infective Agents for Complicated Intra-Abdominal Infections,” “International Clinical Practice Guidelines for Antimicrobial Treatment of Acute Uncomplicated Cystitis and Pyelonephritis in Women,” the 2009 “Diagnosis, Prevention, and Treatment of Catheter-Associated Urinary Tract Infections in Adults,” and the 2005 Association of Medical Microbiology and Infectious Disease Canada Guidelines Committee’s “Complicated Urinary Tract Infection in Adults.” For skin infections, the 2005 “Practice Guidelines for the Diagnosis and Management of Skin and Soft-Tissue Infections” and the 2011 “Management of Patients with Infections Caused by Methicillin-Resistant Staphylococcus aureus: Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA)” were reviewed. Information for skin and soft-tissue infections was also obtained from the October 2010 Emergency Medicine Practice Issue, “Emergency Department Infections in the Era of CA-MRSA.”

Risk Management Pitfalls For Antibiotics In The Emergency Department

  1. “I treated the UTI with nitrofurantoin. I didn’t know it wouldn’t work.” Males and patients with pyelonephritis should not be treated with nitrofurantoin. Due to tissue penetration issues, it should be used only for women with uncomplicated cystitis.
  2. “I treated the patient from the nursing home with urosepsis with cefazolin - that should have been adequate, since most UTIs are caused by E coli.” Remember that nursing home patients and those recently hospitalized may have more resistant bacteria and need antimicrobials with broader coverage.
  3. “He had a hazy, ill-defined possible infiltrate and was otherwise healthy, so I discharged him on amoxicillin-clavulanate.” This is incomplete coverage for pneumonia. Remember to cover for atypical pathogens with azithromycin, doxycycline, or a respiratory fluoroquinolone.
  4. “She had a small area of localized infection on her abdominal wall, so I treated her by prescribing coverage for CA-MRSA with trimethoprim-sulfamethoxazole. I can’t believe how bad it looked when she came back 3 days later.” Incision and drainage is the mainstay of treatment for abscesses.
  5. “Do you remember the diabetic patient with the inner-thigh infection you treated yesterday? He came back today in septic shock.” Don’t forget to consider necrotizing infections when treating skin and soft-tissue infections. Early on, these may not show classic signs and symptoms. Early recognition requires a high degree of clinical suspicion. When in doubt, obtain specialty consultation.
  6. “The patient had a fever and left-lower-quadrant tenderness, so I recommended antibiotics for diverticulitis. How should I have known he would come back with an acute abdomen?” Patients with possible diverticulitis may develop serious complications, such as abscess formation. They should undergo diagnostic imaging.
  7. “I gave antibiotics in the ED right after I evaluated the patient. It wasn’t my fault the CT didn’t get done for 12 hours and the appendix perfed.” A patient with an acute abdomen should have timely surgical consultation, not just antibiotic treatment.
  8. “She was sent from the nursing home with a fever, and her x-ray had an infiltrate, so I treated with azithromycin and admitted her. I can’t believe she was intubated the next day.” Remember that nursing home patients have healthcare-associated pneumonia and need more broad-spectrum coverage.

Tables and Figures

Table 1. Infectious Diseases Society Of America-US Public Health Service Grading System For Rating Recommendations In Clinical Guidelines

Table 2. Spectrum Of Activity Of Commonly Used Antibiotics


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, such as the type of study and the number of patients in the study, will be included in bold type following the reference, where available.

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  2. Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft-tissue infections. Clin Infect Dis. 2005;41(10):1373-1406. (Guideline)
  3. Niska R, Bhuiya F, Xu J. National Hospital Ambulatory Medical Care Survey: 2007 Emergency Department Summary. National health statistics reports, no. 26. Hyattsville, MD: National Center for Health Statistics. 2010. (National survey report)
  4. Safdar N, Handelsman J, Maki DG. Does combination antimicrobial therapy reduce mortality in gram-negative bacteremia? A meta-analysis. Lancet Infect Dis. 2004;4(8):519-527. (Meta-analysis; 5 prospective cohort studies, 2 prospective randomized trials, 10 retrospective cohort studies)
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  20. Abrahamian FM, Moran GJ, Talan DA. Urinary tract infections in the emergency department. Infect Dis Clin North Am. 2008;22(1):73-87. (Review)
  21. Infectious Diseases Society of America, European Society for Microbiology and Infectious Diseases. 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. CID 2011: 52(5):e103-e120. (Guideline)
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Publication Information

Denise Nassisi; Marisa L. Oishi

Publication Date

January 2, 2012

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