Pneumonia is an infection of the lung and respiratory
tract below the level of the larynx. Globally it is a leading cause
of morbidity and mortality, with up to 1.9 million childhood deaths
per year in the developing world.1 Even in industrialized
countries, according to World Health Organization estimates, there
are 4 million cases annually in children <5 years of age.2
This chapter addresses the clinical and radiographic diagnosis
of pneumonia, common viral and bacterial causes, evidence-based
and historically based treatments, and appropriate consultation
and follow-up for children seen in the ED.
An exhaustive discussion of pathogens and preexisting pediatric
pathology is beyond the scope of this text. However, wherever possible,
special mention is made of unusual microbes, changing patterns of
immunization and resistance, and special considerations for children
with underlying medical problems. For the clinician with less pediatric
experience, a brief overview on the use and interpretation of chest
radiographs in this population is included.
In the vast majority of cases, pediatric pneumonia is caused
by viral or bacterial agents, with a smaller number due to unusual
pathogens such as Mycobacterium tuberculosisor
opportunistic organisms such as fungi.
In most cases the etiologic agent is never known. Definitive
microbiologic diagnosis requires invasive procedures such as bronchial
lavage, sampling of pleural effusion for culture, or lung puncture, which are unavailable
or impractical in the ED. Although blood cultures are frequently
performed for the very sick and the very young, they have limited
relevance in the ED. They are used primarily to refine treatment
at a later date, once culture results are known.
Most diagnostic algorithms estimate the likely cause of pneumonia
based on the patient’s age and the presumed incidence and
prevalence of particular microbes for each age group. Detailed summaries
exist in the literature,3 but typical causes of
community-acquired pneumonia in healthy children are listed in (Table 121-1).4 The clinician
still must take into account local and regional epidemics, individual
immunization status, and underlying health problems that may influence
which pathogens are likely. Infections vary considerably across
the spectrum of age, and a few general rules and specific exceptions
are described below.
Table 121-1 Age-Specific
Causes of Pneumonia in Otherwise Healthy Children |Favorite Table|Download (.pdf)
Table 121-1 Age-Specific
Causes of Pneumonia in Otherwise Healthy Children
|Age Group||Pathogen (in order of frequency)|
|1–3 mo||Pneumonitis syndrome, usually afebrile: Chlamydia
trachomatis, RSV, other respiratory viruses, Bordetella
|1–24 mo||Mild to moderate pneumonia: RSV, other respiratory viruses, Streptococcus
pneumoniae, Hib, NTHi, C. trachomatis, Mycoplasma
|2–5 y||Respiratory viruses, S. pneumoniae, Hib,
NTHi, M. pneumoniae, C. pneumoniae|
|6–18 y||M. pneumoniae, S. pneumoniae, C.
pneumoniae, NTHi, influenzavirus A or B, adenovirus, other
|All ages||Severe pneumonia requiring intensive care unit admission: S.
pneumoniae, Staphylococcus aureus, ...|