Parainfluenza

• Causes, incidence, and risk factors

  There are four types of parainfluenza virus, all of which can cause upper respiratory infections or lower respiratory infections (pneumonia) in adults and children. The virus is responsible for approximately 40-50% of croup cases and 10-15% of bronchiolitis and bronchitis cases and some pneumonias.

  The exact number of cases of parainfluenza is unknown but suspected to be very high. Sometimes the viruses cause only a runny nose and other symptoms that may be diagnosed as a simple cold rather than parainfluenza.

  Infections are most common in fall and winter. Parainfluenza infections are most severe in infants and become less severe with age. By school age, most children have been exposed to parainfluenza virus. Most adults have antibodies against parainfluenza although they can get repeat infections.

• Symptoms

  Symptoms vary depending on the type of infection. Cold-like symptoms consisting of a runny nose and mild cough are common. Life-threatening respiratory symptoms can be seen in young infants with bronchiolitis.

  In general, symptoms may include:

  • Chest pain
  • Congestion
  • Cough
  • Croup
  • Runny nose
  • Shortness of breath
  • Sore throat
  • Wheezing
• Signs and tests

  A physical exam may show sinus tenderness, swollen glands, and a red throat. The doctor will listen to the lungs and chest with a stethoscope. Abnormal sounds, such as crackling or wheezing, may be heard.

  Tests that may be done include:

  • Arterial blood gases
  • CBC
  • Swab of nose for rapid viral test
• Treatment

  There is no specific treatment for the viral infection. Specific treatments are available for the symptoms of croup and bronchiolitis.

• Expectations (prognosis)

  Most infections in adults and older children are mild and recovery takes place without treatment, unless the person is very old or has an abnormal immune system. Medical intervention may be necessary if breathing difficulties develop.

• Complications

  Secondary bacterial infections are the most common complication. Airway obstruction in croup and bronchiolitis can be severe, even life-threatening.

• Calling your health care provider

  Call your health care provider if your child develops croup, wheezing or any other type of breathing difficulty. You may wish to call your health care provider for children under 18 months of age with any type of upper respiratory symptoms.

• Prevention

  There are no vaccines available for parainfluenza. Avoiding crowds to limit exposure during peak outbreaks may decrease the likelihood of infection.

  Limiting exposure to daycare centers and nurseries may delay infection until the child is older.

Review Date: 3/2/2009

Reviewed By: Daniel Levy, MD, PhD, Infectious Diseases, Greater Baltimore Medical Center, Baltimore, MD. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.