RESPIRATORY INFECTIONS

PRICING INFO


References:
Infection Treatment Other
Pneumonia,
community-acquired

(ADULTS)
2007 IDSA recommendations

  • Recommended outpatient treatment in patients with any of the following conditions:
    • Chronic heart, lung, liver, or kidney disease
    • Diabetes mellitus
    • Alcoholism
    • Malignancies
    • Asplenic
    • Immunosuppressing conditions or use of immunosuppressing drugs
    • Use of antimicrobials within the previous 3 months (in which case an alternative from a different class should be selected)
    • Other risks for drug-resistant S. pneumoniae infection
    • Regions with a high rate (> 25%) of infection with high-level (MIC, ≥ 16 mcg/mL) macrolide-resistant S. pneumoniae

  • Use one of the following regimens:
Symptoms / Diagnosis
  • Symptoms of pneumonia include cough, fever, sputum production, shortness of breath, hypoxia, and pleuritic chest pain
  • Chest X-ray should be performed to confirm the diagnosis
  • The ACCP and ACP state that for healthy adults < 70 years old, the absence of all the following makes the diagnosis of pneumonia very unlikely and a chest X-ray is not indicated:
    • Tachycardia (heart rate > 100 beats/min)
    • Tachypnea (respiratory rate > 24 breaths/minute)
    • Fever (oral temp > 38° C or 100.4° F)
    • Abnormal findings on chest exam including egophony (increased resonance of voice sounds heard when auscultating the lungs), fremitus (voice vibrations transmitted to the chest wall that are heard or felt with the hands), and rales (rattling sound) [11,12]

  • For outpatient treatment, sputum and blood cultures are not typically performed
  • In 2017, the FDA approved the procalcitonin (PCT) blood test to help distinguish bacterial vs viral pneumonia. High levels of PCT suggest a bacterial infection, while low levels suggest a viral infection or noninfectious causes. [FDA press release]

Etiology
  • A study published in 2015 found the following etiologies of community-acquired pneumonia in 2259 hospitalized adults:
    • No pathogen detected - 62%
    • Rhinovirus- 9%
    • Influenza virus - 6%
    • Streptococcus pneumoniae - 5%
    • Human metapneumovirus - 4%
    • Respiratory syncytial virus - 3%
    • Parainfluenza virus 1,2,3 - 2%
    • Coronaviruses- 2%
    • Mycoplasma pneumoniae - 2%
    • S. aureus - 2%
    • Adenovirus- 1%
    • L. pneumophila - 1%
    • Enterobacteriaceae - 1% [10]

Inpatient vs outpatient treatment
  • The CURB-65 criteria can be used to help guide decision-making regarding inpatient vs outpatient treatment

    • CURB-65 criteria include:
      • Confusion - disorientation to person, place, or time
      • BUN - > 20 mg/dl (may be excluded in office settings)
      • Respiratory rate - ≥ 30 breaths/min
      • Low Blood pressure - systolic < 90 mmHg or diastolic ≤ 60 mmHg
      • Age ≥ 65 years

  • Patients receive one point for each criteria they meet
  • Patients with a score of 0 - 1 can be treated as outpatients
  • patients with a score ≥ 2 should be hospitalized [1]

  • 30-day mortality based on CURB-65 score:
    • 0 - 0.7%
    • 1 - 2.1%
    • 2 - 9.2%
    • 3 - 14.5%
    • 4 - 40%
    • 5 - 57%

Recent Studies
  • Beta-lactam vs Beta-lactam + Macrolide vs Fluoroquinolone in CAP, NEJM (2015) - 2283 adults (median age 70 years) with CAP who were admitted to the hospital were randomized to one of the three treatments. Preferred beta-lactam therapy was amoxicillin, amoxicillin plus clavulanate, or a third-generation cephalosporin.
    PRIMARY OUTCOME: 90-day mortality
    RESULTS: At 90 days, there was no significant difference in the primary outcome - beta-lactam - 9%; beta-lactam + macrolide - 11.1%; fluoroquinolone - 8.8% [PubMed abstract]

  • Adjuvant Prednisone vs Placebo for CAP, Lancet (2015) - 785 adults with CAP who were admitted to the hospital were randomized to prednisone 50 mg once daily for 7 days or placebo
    PRIMARY OUTCOME: Time to clinical stability defined as time (days) until stable vital signs for at least 24 hours
    RESULTS: Median time to clinical stability was shorter in the prednisone group (3 days) than in the placebo group (4.4 days) [PubMed abstract]


Infection Treatment Other
Pneumonia,
community-acquired

(PEDIATRIC)
2011 IDSA recommendations for children ≥ 3 months old

NOTE: Recommendations are for previously healthy, appropriately-immunized patients

First-line outpatient treatment for presumed bacterial pneumonia
Alternatives
  • Cefpodoxime - 10 mg/kg/day given in 2 divided doses for 7 - 10 days ($$-$$$)
  • Cefuroxime - 30 mg/kg/day (max 1000 mg/day) given in 2 divided doses for 7 - 10 days ($-$$)
  • Cefprozil - 30 mg/kg/day (max 1000 mg/day) given in 2 divided doses for 7 - 10 days ($-$$)
  • Ceftriaxone - 50 - 100 mg/kg/day IM (max 2000 mg/day) given once daily for 7 - 10 days ($)
  • Levofloxacin ($$-$$$ for suspension, $ tablet)
    • 6 months - 5 years old - 16 - 20 mg/kg/day given in 2 divided doses for 7 - 10 days
    • 5 - 16 years old - 8 - 10 mg/kg/day (max 750 mg/day) given once daily for 7 - 10 days
  • Linezolid ($$$$)
    • < 12 years old - 30 mg/kg/day given in 3 divided doses for 7 - 10 days
    • ≥ 12 years old - 20 mg/kg/day (max 1200 mg/day) given in 2 divided doses for 7 - 10 days

For suspected Mycoplasma pneumoniae or Chlamydophila pneumoniae:
Symptoms
  • Symptoms of pneumonia include cough, fever, sputum production, shortness of breath, hypoxia, and pleuritic chest pain
  • Infants < 6 months old with suspected bacterial pneumonia should be hospitalized
  • Patients with respiratory distress should be hospitalized [8]
    • Signs of respiratory distress include:
      • Tachypnea
        • Defined as respiratory rate (breaths/min):
          • Age 0–2 months: > 60
          • Age 2–12 months: > 50
          • Age 1–5 Years: > 40
          • Age > 5 Years: > 20
      • Dyspnea
      • Retractions (suprasternal, intercostals, or subcostal)
      • Grunting
      • Nasal flaring
      • Apnea
      • Altered mental status
      • Pulse oximetry measurement < 90% on room air

Workup
  • Blood and sputum cultures should not be routinely obtained for outpatient treatment
  • Routine chest X-ray is not necessary in children well enough to be treated as outpatients. Patients with signs of respiratory distress should have a chest X-ray.
  • In children who recover uneventfully from pneumonia, follow-up chest X-ray is not necessary [8]

Etiology
  • In preschool-aged children (2 - 5 years), viruses are responsible for the vast majority of pneumonias, and antibiotics are not routinely required

    • A study published in 2015 found the following etiologies of community-acquired pneumonia in 2222 hospitalized children (median age 2 years):
      • Respiratory Syncytial Virus (RSV) - 28%
      • Human rhinovirus - 27%
      • Human metapneumovirus (HMPV) - 13%
      • Adenovirus - 11%
      • M. pneumoniae - 8%
      • Parainfluenza virus - 7%
      • Influenza virus - 7%
      • Coronavirus - 5%
      • S. pneumoniae - 4%
      • S. aureus - 1%
      • S. pyogenes - 1% [9]

  • Streptococcus pneumoniae is the most common cause of bacterial pneumonia. Haemophilus influenzae is uncommon since the advent of the H. flu vaccine.
  • Mycoplasma pneumonia is marked by slowly progressing cough, malaise, sore throat, and low-grade fever developing over 3–5 days. It's unclear if antibiotics are beneficial in children with Mycoplasma pneumonia. [8]

Infection Treatment Other
Influenza

(flu)
Pediatric - CDC recommendations

  • Acute infection
    • Oseltamivir (Tamiflu®)
      • Age 14 days - 1 year: 3 mg/kg/dose twice daily for 5 days
      • Age > 1 year (dose based on weight)
        • ≤ 15 kg: 30 mg twice a day for 5 days
        • > 15 to 23 kg: 45 mg twice a day for 5 days
        • > 23 to 40 kg: 60 mg twice a day for 5 days
        • > 40 kg: 75 mg twice a day for 5 days ($$)
    • Zanamivir (Relenza®)
      • Age ≥ 7 years: 10 mg (inhalation powder) twice a day for 5 days ($$)

  • Prophylaxis
    • Oseltamivir (Tamiflu®)
      • Age 3 months - 1 year: 3 mg/kg/dose once daily for 7 days
      • Age > 1 year (dose based on weight)
        • ≤ 15 kg: 30 mg once a day for 7 days
        • > 15 to 23 kg: 45 mg once a day for 7 days
        • > 23 to 40 kg: 60 mg once a day for 7 days
        • > 40 kg: 75 mg once a day for 7 days ($$)
    • Zanamivir (Relenza®)
      • Age ≥ 5 years: 10 mg (inhalation powder) once daily for 7 days ($$)

Adults - CDC recommendations


Symptoms / Diagnosis
  • Symptoms of the flu are similar to other common viral syndromes and include fever, cough, sore throat, nasal congestion, body aches, and fatigue
  • The flu is most often diagnosed clinically or with in-office rapid influenza diagnostic tests. These tests work by detecting influenza antigens (immunoassays) or by amplifying and detecting influenza nucleic acids. Some antigen tests are read by the person performing the test (operator) and others use an instrument to read the results. Instrument-read tests are more sensitive than operator-read tests and nucleic acid tests are the most sensitive.
  • The table below lists the sensitivities of the tests for detecting influenza A and B when reverse transcriptase PCR is used as the reference standard. All of the tests have high specificities (> 95%) which means there are few false-positives.
  • Reference [13]
Test Sensitivity
Operator-read antigen 54%
Instrument-read antigen 77 - 80%
Nucleic acid tests 92 - 95%

Oseltamivir and zanamivir
  • The strongest evidence for a benefit from oseltamivir and zanamivir is when they are initiated within 48 hours of symptom onset
  • In trials, oseltamivir reduced the length of flu symptoms by about 16 hours, but increased the incidence of nausea and vomiting
  • The overall benefits of oseltamivir are questionable - see Cochrane meta-analysis and Roche meta-analysis for more

CDC recommendations on who to treat
  • The CDC recommends antivirals (oseltamivir or zanamivir) in patients who are at "high-risk" for flu-related complications.

  • High-risk defined as having one of the following:
    • Children aged < 5 years (especially those < 2 years)
    • Adults aged ≥ 65 years
    • Persons with certain chronic medical conditions (asthma, COPD, DM, CAD, stroke, kidney disease, liver disease, hematologic disorders, neurologic and neurodevelopment conditions, intellectual disability, developmental delay, muscular dystrophy)
    • Immunosuppressed patients (e.g. HIV, medications, cancer)
    • Pregnant or postpartum (within 2 weeks after delivery)
    • ≤ 18 years old and receiving chronic aspirin therapy
    • Morbid obesity (BMI ≥ 40)
    • American Indians/Alaska Natives
    • Nursing home residents and other chronic-care facilities

  • For outbreaks in institutional settings - CDC recommends antiviral chemoprophylaxis for a minimum of 2 weeks, and continuing for 10 days after the last known case is identified. Antiviral chemoprophylaxis should be considered for all exposed residents, including those who have received influenza vaccination, and for unvaccinated institutional employees. [14]

Studies
  • Neuraminidase inhibitors during pregnancy, BMJ (2017) RESULTS: This large multinational register study found no increased risks of adverse neonatal outcomes or congenital malformations associated with exposure to neuraminidase inhibitors during embryo-fetal life. [PubMed abstract]