Viral Pneumonia

Key Features

Essentials of Diagnosis

• Upper respiratory infection prodrome (fever, coryza, cough, hoarseness)

• Wheezing or rales

• Myalgia, malaise, headache (older children)

General Considerations

• Viral infection is a common cause of community-acquired pneumonia in children; responsible viruses in most cases follow:

  • Respiratory syncytial virus (RSV)

  • Parainfluenza (1, 2, and 3) viruses

  • Influenza (A and B) viruses

  • Human metapneumovirus

• Viral pneumonia is most common in children younger than 2 years

• Viral infections may predispose to bacterial pneumonia

Clinical Findings

Symptoms and Signs

• Wheezing or stridor may be prominent in viral disease

• However, other findings that are similar to those in bacterial pneumonia include

  • Cough

  • Signs of respiratory distress (tachypnea, retractions, grunting, and nasal flaring)

  • Rales and decreased breath sounds

Differential Diagnosis

• Same as for bacterial pneumonia

• Patients with prominent wheezing may have

  • Asthma

  • Airway obstruction caused by foreign body aspiration

  • Acute bacterial or viral tracheitis

Diagnosis

Laboratory Findings

• Peripheral white blood cell count

  • Can be normal or slightly elevated

  • Not useful in distinguishing viral from bacterial disease

• Rapid viral diagnostic methods, such as fluorescent antibody tests, enzyme-linked immunosorbent assay, and/or polymerase chain reaction (PCR), should be performed on nasopharyngeal secretions to identify a viral etiology in high-risk patients as well as for epidemiology or infection control

Imaging

• Chest radiography

  • Frequently show perihilar streaking, increased interstitial markings, peribronchial cuffing, or patchy bronchopneumonia

  • Lobar consolidation or atelectasis may occur

  • Hyperinflation of the lungs may occur when involvement of the small airways is prominent

Treatment

• General supportive care for viral pneumonia does not differ from that for bacterial pneumonia

• Because bacterial disease often cannot be definitively excluded, antibiotics may be indicated.

• Patients at risk for life-threatening RSV infections should be hospitalized and ribavirin should be considered

• Children with suspected viral pneumonia should be placed in respiratory isolation

Outcome

Complications

• Viral pneumonia or laryngotracheobronchitis may predispose the patient to subsequent bacterial tracheitis or pneumonia as immediate sequelae

• Bronchiolitis obliterans or severe chronic respiratory failure may follow adenovirus pneumonia

• Bronchiectasis, chronic hypersensitivity pneumonia, and unilateral hyperlucent lung (Sawyer-James syndrome) may follow measles, adenovirus, and influenza pneumonias

Prognosis

• Most children recover uneventfully

• Patients with adenovirus infection or those concomitantly infected with RSV and second pathogens (such as influenza, adenovirus, cytomegalovirus, or Pneumocystis jirovecii) have a worse prognosis

References