Rosen & Barkin's 5-Minute Emergency Medicine Consult (270 page)

• Decreased immunocompetence, increased risk of systemic spread, increased exposure to health care settings, may have comorbid conditions.
  
• If institutionalized consider the infectious implications of multiple potential sick contacts.
  

• CXR:
  
  • In patients with PE finding of cardiopulmonary disease and patients with unclear fever source
    
• CT or MRI may be indicated if lumbar puncture or osteomyelitis is considered, respectively.
  

• The differential diagnosis is very broad as listed above, but is generally categorized as infectious vs. noninfectious, and by immunocompetency.
  

TREATMENT

• No specific field interventions required
  
• Monitoring and IV access should be obtained in the field for unstable patients or patients with altered mental status.
  

• ABCs for unstable patients.
  
• Initiate early broad-spectrum antibiotics for patients with suspected sepsis or unstable vital signs, particularly those who are at high risk for serious bacterial infection.
  

• Antipyretics:
  
  • Generally either acetaminophen or NSAIDs
    
    • Inhibit the cyclooxygenase enzyme, thereby blocking synthesis of prostaglandins.
      
• Empiric antibiotics for neutropenic patients:
  
  • Combination therapy:
    
    • Extended spectrum β-lactam (ceftazidime, piperacillin) with an aminoglycoside
      
  • Monotherapy:
    
    • Cefepime
      
    • Ceftazidime
      
    • Imipenem
      
• Empiric antibiotics for asplenic patients for encapsulated bacteria
  
• Empiric antiviral therapy for patients with encephalitis and potential disseminated viral infections (e.g., recent organ or bone marrow transplant patients, AIDS patients)
  
• External cooling mechanism rarely indicated
  

• Antipyretics:
  
  • Acetaminophen: 650–1,000 mg PO/PR q4–6h; do not exceed 4 g/24h
    
  • Aspirin: 650 mg PO q4h; do not exceed 4 g/24h
    
  • Ibuprofen: 800 mg PO q6h
    
• Antibiotics:
  
  • Cefepime: 2 g IV q12
    
  • Ceftazidime: 2 g IV q8
    
  • Gentamicin or tobramycin (D): 2 mg/kg IV load then 1.7 mg/kg q8h + piperacillin/tazobactam (B) 3.375 g IV q4h or ticarcillin/clavulanate (B) 3.1 g IV q4h
    
  • Imipenem/cilastatin: 500–1,000 mg IV q8h
    
  • Meropenem (B): 1 g IV q8h
    
  • Ciprofloxacin: 750 mg PO BID + amoxicillin/clavulanate (B) 875 mg PO BID
    
• Antivirals:
  
  • Herpes simplex virus and varicella-zoster virus (VZV):
    
  • Acyclovir 10–15 mg/kg IV q8h
    
  • Influenza A and B:
    
  • Oseltamivir 75 mg PO q12h
    

FOLLOW-UP

• Patients with unstable vital signs require ICU admission.
  
• When identified, the underlying source of the fever usually determines the disposition.
  
• Certain high-risk groups who have fever without an identifiable source:
  
  • Neutropenic patients
    
  • Immunosuppressed or immunocompromised patients
    
  • Asplenic patients
    
  • IV drug abusers
    
• Lower thresholds for admission in patients older than 60 yr and diabetics
  

Immunocompetent patients with stable vital signs and an identified source of fever or a high suspicion of a nonthreatening viral infection may be safely discharged.

The suspected etiology of the fever determines the referral to a primary care physician or a specialist.

Appropriate outpatient treatment and follow-up for further outpatient assessment of the suspected etiology.

• Screening lactates for sepsis.
  
• Early, empiric, and broad-spectrum antibiotic coverage for all septic patients.
  
• Consider all potential sources of infection.
  
• Careful consideration for the immunosuppressed, elderly, and IV drug users.
  

• Cunha BA. Fever of unknown origin: Focused diagnostic approach based on clinical clues from the history, physical examination, and laboratory tests.
  Infect Dis Clin North Am
  . 2007;21:1137–1187.
  
• Freifeld AG, Bow EJ, Sepkowitz KA, et al. Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the Infectious Diseases Society of America.
  Clin Infect Dis.
  2011;52:e56–e93.
  
• Mackowiak PA, Wasserman SS, Levine MM. A critical appraisal of 98.6 degrees F, the upper limit of the normal body temperature, and other legacies of Carl Reinhold August Wunderlich.
  JAMA.
  1992;268(12):1578–1580.
  

CODES

• 780.60 Fever, unspecified
  
• 780.61 Fever presenting with conditions classified elsewhere
  

BASICS

• Fever is defined as a temperature of 38°C (100.4°F) rectally:
  
  • Oral and tympanic temperatures are generally 0.6°C–1°C lower.
    
• Tympanic temperatures are not accurate in children younger than 6 mo.
  
• Axillary temperatures are generally unreliable.
  
• Children who are afebrile but have a reliable history of documented fever should be considered to be febrile to the degree reported.
  

• Bacteremia (
  Haemophilus influenzae
  type B,
  Streptococcus pneumoniae),
  viral illness, often accompanied by exanthem (varicella, roseola, rubella), coxsackievirus (hand-foot-and-mouth disease), abscess:
  
  • H. influenzae
    type B and
    S
    .
    pneumoniae
    vaccines have reduced incidence of Haemophilus and pneumococcal disease
    
• CNS: Meningitis, encephalitis
  
• Head, eyes, ears, neck, and throat (HEENT): Otitis media, facial cellulitis, orbital/periorbital cellulitis, pharyngitis (group A β-hemolytic streptococcus, herpangina, adenovirus pharyngoconjunctival fever), viral gingivostomatitis (herpes and coxsackievirus), cervical adenitis, sinusitis, mastoiditis, conjunctivitis, peritonsillar/retropharyngeal abscess
  
• Respiratory: Croup (paramyxovirus), epiglottitis, bronchiolitis (respiratory syncytial virus [RSV]), pneumonia, empyema, influenza
  
• Cardiovascular: Purulent pericarditis, endocarditis, myocarditis
  
• Genitourinary (GU): Cystitis, pyelonephritis
  
• GI: Bacterial diarrhea, intussusception, appendicitis, hepatitis
  
• Extremity: Osteomyelitis, septic arthritis, cellulitis
  
• Miscellaneous: Herpes simplex virus infection in the neonate, Kawasaki disease, vaccine (DPT) reaction, heat exhaustion/stroke, factitious, familial dysautonomia, thyrotoxicosis, collagen vascular disease, vasculitis, rheumatic fever, malignancy, drug induced, overbundling (uncommon, recheck 15 min after unbundling)
  

DIAGNOSIS

• Clinical appearance must be evaluated. Airway, breathing, and circulation (especially dehydration with impaired perfusion/color) need specific evaluation.
  
• Toxicity associated with lethargy, delayed capillary refill, hypoventilation/hyperventilation, weak cry, decreased PO intake; purpuric or petechial rash, and/or hypotonia. Initial observation is crucial in this evaluation.
  
• Tachycardia or tachypnea may be the only finding in children with serious underlying condition.
  
• Fever with a temperature >38°C can raise a child’s heart rate by 10 bpm for each degree Fahrenheit.
  
• Temperature >40°C have been associated with an elevated bacteremia rate in children <24 mo.
  
• Altered mental status:
  
  • Lethargy presenting with decreased level of consciousness
    
  • Irritability
    
  • Impaired interaction with environment, parents, physician, toys
    
• Physical exam (PE) to search for underlying condition
  
• Tachypnea and low oximetry are the most sensitive signs for pneumonia. Also useful are rales, hypoxemia, cough >10 days, and fever >5 days.
  
• Risk factors for occult UTI include female sex, uncircumcised boys, fever without source, and fever >39°C.
  
• Febrile seizures
  
• Temperatures >42°C often have a noninfectious cause.
  
• Serious infection may occur in the absence of fever.
  
• Antipyretics may change findings without impacting underlying disease. This may be useful in evaluation of patient, esp. with respect to mental status
  
• ∼20% of children will have fever without definable source after history and PE.