Viral Pneumonia

Paul C. Stillwell, MD, FAAP

Introduction/Etiology/Epidemiology

•Pneumonia in children is categorized in the following ways to help differentiate the potential infecting organisms, treatment strategies, and expected outcomes:

—Community-acquired pneumonia (CAP) in an otherwise healthy child

—Health care–related pneumonia or hospital-acquired pneumonia

—Pneumonia in an immunocompromised patient

—Pneumonia with complications (effusion, empyema, abscess)

•The incidence of CAP is highest in children <4 years of age— approximately 35–40 per 1,000, compared to only 20 per 1,000 school-aged children and 10 per 1,000 teenagers and adolescents.

•Pneumonia is a common cause of death in children who reside in regions poor in health resources.

•Viral lower respiratory tract infections are the most common etiologic origin of CAP and account for approximately 65% of infections in all children and approximately 80% in children <2 years of age.

•Viral coinfections occur 15%–20% of the time, and viral-bacterial infections occur about 5% of the time. In particular, viral-bacterial coinfections have been well documented between influenza virus and Streptococcus pneumoniae, Staphylococcus aureus, and group A Streptococcus.

•The most common viruses identified as causing pneumonia are

—Respiratory syncytial virus

—Human rhinovirus

—Human metapneumovirus

—Adenovirus

—Parainfluenza virus types 1–3

—Influenza virus A and B

—Coronaviruses

•Other viruses can cause problematic pneumonia in the immunocompromised host, and the viruses listed here can cause life-threatening pneumonia in children with chronic lung conditions or those with abnormal host defenses.

•Varicella pneumonia occurs rarely in older children and young adults; the frequency has declined since the Varicella vaccine became available.

•The most common symptoms of pneumonia are cough, fever, and shortness of breath.

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