Find information on medical topics, symptoms, drugs, procedures, news and more, written for the health care professional.

* This is a professional Version *

Overview of Viral Respiratory Infections

by Craig R. Pringle, BSc, PhD

(See Bronchiolitis, see Croup, and see Pneumonia.)

Viral infections commonly affect the upper or lower respiratory tract. Although these infections can be classified by the causative virus (eg, influenza), they are generally classified clinically according to syndrome (eg, the common cold, bronchiolitis, croup). Although specific pathogens commonly cause characteristic clinical manifestations (eg, rhinovirus typically causes the common cold, respiratory syncytial virus [RSV] typically causes bronchiolitis), each can cause many of the viral respiratory syndromes (see Table: Causes of Common Viral Respiratory Syndromes).

Causes of Common Viral Respiratory Syndromes

Syndrome

Common Causes

Less Common Causes

Bronchiolitis

RSV

Influenza viruses

Parainfluenza viruses

Adenoviruses

Rhinoviruses

Common cold

Rhinoviruses

Coronaviruses

Influenza viruses

Parainfluenza viruses

Enteroviruses

Adenoviruses

Human metapneumoviruses

RSV

Croup

Parainfluenza viruses

Influenza viruses

RSV

Influenza-like illness

Influenza viruses

Parainfluenza viruses

Adenoviruses

Pneumonia

Influenza viruses

RSV

Adenoviruses

Parainfluenza viruses

Enteroviruses

Rhinoviruses

Human metapneumoviruses

Coronaviruses

RSV = respiratory syncytial virus.

Severity of viral respiratory illness varies widely; severe disease is more likely in the elderly and infants. Morbidity may result directly from viral infection or may be indirect, due to exacerbation of underlying cardiopulmonary conditions or bacterial superinfection of the lung, paranasal sinuses, or middle ear.

Diagnosis

Detection of viral pathogens by PCR, cell culture, or serologic tests is generally too slow to be useful for patient care but is useful for epidemiologic surveillance (ie, identifying and determining the cause of an outbreak). More rapid diagnostic tests are available for influenza and RSV, but the utility of these tests for routine care is not clear; they should be reserved for situations in which pathogen-specific diagnosis affects clinical management. Management decisions are usually based on clinical data and epidemiology.

Treatment

Treatment of viral respiratory infections is usually supportive. Antibacterial drugs are ineffective against viral pathogens, and prophylaxis against secondary bacterial infections is not recommended. Antibiotics should be given only when secondary bacterial infections develop. In patients with chronic lung disease, antibiotics may be given with less restriction.

Aspirin should not be used in patients who are 18 yr and have respiratory infections because Reye syndrome is a risk.

Some patients continue to cough for weeks after resolution of an URI; these symptoms may lessen with use of an inhaled bronchodilator or corticosteroids.

In some cases, antiviral drugs are useful. Amantadine, rimantadine, oseltamivir, and zanamivir are effective for influenza. Ribavirin, a guanosine analog that inhibits replication of many RNA and DNA viruses, may be considered for severely immunocompromised patients with lower respiratory tract infection due to RSV. Palivizumab, a monoclonal antibody to RSV fusion protein, is being used to prevent RSV infection in certain high-risk infants.

Resources In This Article

Drugs Mentioned In This Article

  • Drug Name
    Select Trade
  • VIRAZOLE
  • TAMIFLU
  • FLUMADINE
  • RELENZA
  • No US brand name
  • SYNAGIS

* This is a professional Version *