Parainfluenza

Definition:

A group of viruses belonging to the Parainfluenza virus that cause upper and lower respiratory infections.

Causes, incidence, and risk factors:

There are four serotypes of Parainfluenza virus, all of which are associated with causing disease. Parainfluenza can cause upper respiratory infections and lower respiratory tract infections (pneumonia) in both adults and children. The virus is especially important in children because it is responsible for approximately 40 percent to 50 percent of all cases of croup and 10 percent to 15 percent of bronchiolitis and bronchitis and some pneumonias. The incidence of parainfluenza is unknown but suspected to be very high. Illness causing only a runny nose and cold-like symptoms may pass as a simple cold rather than parainfluenza. Risk factors include young 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. For detailed symptoms see the specific disease.

runny nose (rhinorrhea)
congestion
cough
sore throat
croup
wheezing
bronchiolitis (diagnosis)
bronchitis (diagnosis)
shortness of breath
chest pain

Signs and tests:

sinus tenderness
red pharynx (throat)
swollen glands at neck
crackles or wheezing in lungs
fever

Tests:

swab of nose for rapid viral test
viral culture (very expensive; cultures generally are not performed for reasons other than to determine the nature of an epidemic)
CBC
arterial blood gases

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 they have abnormal immune systems or are very old. Medical intervention may be necessary if breathing difficulties or respiratory distress 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 upper respiratory symptoms (even without evidence of airway obstruction).

Prevention:

There are no vaccines available for parainfluenza. Parainfluenza infections may be seasonal usually in the fall and winter. Avoiding crowds and limiting exposure during peak outbreaks may decrease the likelihood of infection. Parainfluenza infections are most severe in infants and become less severe with age. Limiting exposure, such as day-care and full nurseries, may delay infection until the child is older.

Review Date: 12/7/2001
Reviewed By: Camille Kotton, M.D., Infectious Diseases Division, Massachusetts General Hospital and Brigham and Women's Hospital, Boston, MA. Review provided by VeriMed Healthcare Network.

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