Respiratory

Community Acquired Pneumonias

IDSA Guidelines for CAP - click here

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Clinical Manifestations

1. Fever
2. Tachypnea- (greater than 50/min in < 1 yr.olds and >40/min in > 1 year olds) and retractions are strong indicators of lower respiratory infection.
3. Grunting, and audible wheezing
4. Often proceeded by upper respiratory tract infection.
5. Type of cough not specific.  Children usually do not expectorate. 
     a. Paroxysmal cough associated with pertussis and viral infections
     b. Staccato cough associated with C.trachomatis pneumonia in infants
6. Abdominal pain and vomiting
7. Chest Pain- secondary to pleural irritation or retractions leading to muscle pain
8. Auscultation- crackles, wheezing, bronchial breath sounds, tactile fremitus, egophony, dullness
9. Color-pink or cyanotic?
10 Meningismus may be present with upper lobe pneumonias

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Chest Radiograph

1. Chest radiograph is not necessary if the patient is well appearing and there is positive clinical evidence for pneumonia. 
2. Chest radiograph will not differentiate one etiologic agent from another

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A chest X-ray showing a very prominent wedge-shape area of airspace consolidation in the right lung characteristic of acute bacterial lobar pneumonia https://en.wikipedia.org/wiki/Pneumonia

 

Epidemiology

1. Age- incidence of viral etiology decreases with age and incidence of bacterial increases 
2. RSV and influenza more common in late fall and winter. Mycoplasma present throughout the year and incidence increase with age.  No seasonal variation with Chlamydia pneumonia.
3. Immunization status- influenza, pneumococcal and HIB vaccines 

 

 

Etiology of Community Acquired Pneumonia

1. RSV >Rhinoviruses > Parainfluenzae > Adenoviruses
2. Streptococcus pneumonia > Hemophilus > Mycoplasma > Chlamydia pneumoniae > Group A Streptococcus > Chlamydia pneumoniae

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Diagnosis

1. In ambulatory patients, CBC and total white count, blood culture, and chest radiographs will not be helpful in differentiating causes of pneumonia. Urinary antigen tests not recommended.
2. Viral etiologies may be diagnosed with rapid screening tests of nasopharyngeal secretions (RSV, parainfluenza, influenza) using direct fluorescent antibody test (DFA)
3. Blood cultures and pleural fluid is positive in less than 20% of cases 
4. PCR for Chlamydia, Mycoplasma, and bacteria are not yet perfected for clinical use 
5. Serology for M. pneumoniae, C pneumoniae, and S. pneumococcus are available on a limited basis. 
6. Sputum not helpful because not well correlated with lower respiratory pathogens. 
7. In very ill patients, bronchoscopy may be helpful in obtaining samples for culture.
8. Thorocentesis is indicated if pleural effusion or empyema is present. 

 

Treatment 

  • Ambulatory (mild to moderate symptoms)- immunization status should influence decision
         
    • If less than 4 years old, the majority of cases will be of viral origin.  Therefore, no treatment is an option.  If you suspect bacterial etiology, Amoxicillin (90 mg/kg/day in  3 divided doses) is the drug of choice. Azithromycin not recommended becaue of 40% resistance of pneumococcus in CAP.  If non-serious amoxicillin allergy, oral cefuroxime, cefprozil, or cefpodoxime are alternatives. May also use Clindamycin.
    • In children older than 4 years of age, viruses as well as bacteria must be considered.  The options include no antibiotic therapy.  If you decide to treat, must cover  S.pneumoniae.
  • There have been no clinical studies in children that demonstrate that macrolides improve the clinical course in Mycoplasma infections. 
  • Chlamydia trachomatis- oral macrolide
  • Follow-up is important.  Patients need to be re-evaluated if there is an increase in temperature, more work of breathing, toxic appearance, vomiting, and lethargy. 
  • Repeating chest radiographs is necessary if there is not clinical improvement or worsening of symptoms.  It may take up to six before the chest radiograph is normal in patients responding to treatment. 

 

References

  1. Wubbel L. et al. Etiology and Treatment of community acquired pneumonia in ambulatory children Pediatric Infect. Dis. J. 1999 
  2. McIntosh K.  Community-Acquired Pneumonia in Children NEJM Feb 2002
  3. Gaston Benjamin. Pneumonia. Pediatrics in Review  April 2002
  4. Shah S. et al. Risk of Bactereemia in Young Children with Pneumonia aTreated as Outpatients. Archives of Pediatrics and Adolescent Medicine. April 2003
  5. Tan T. et al. Clinical Characteristics of Children with Complicated Pneumonia Caused by Streptococcal pneumonia.Pediatrics July 2002
  6. Lynch T. Predictive Factors of Pneumonia in Children Pediatrics 2004
  7. Michelow I. et al. Community-Acquired Pneumonia in Hospitalized Children  Pediatrics 2004
  8. Schultz K. et al. The Changing Face of Pleural Empyemas in Children: Epidemiology and Management.  Pediatrics June 2004
  9. Leung C. et al. Severe Acute Respiratory Syndrome Among Children.  Pediatrics June 2004 
  10. Durbin W. and Stille C. Pneumonia. Pediatrics in Review May 2008
  11. Bradley J.S. et al. Management of Community Acquired Pneumonia in Infants older than 3 months of age: Clinical Practice Guidlines by the Pediatric Infectious Disease Society and Infectious Disease Society of America.  2011
  12. Cohen E. et al. The Long-term Outcomes of Pediatric Pleural Empyema.  Arch Pediatr Adolesc Med Nov 2012