Overview, Causes, & Risk Factors

Croup is an infection of the tissues around the vocal cords in young children.It causes a characteristic barking cough.

What is going on in the body?

The symptoms of croup are caused by the swelling and inflammation of thetissues around the larynx and vocal cords. The diameter of the upper airway inyoung children is narrow to begin with, so this swelling further reduces thesize of the airway. This makes breathing noisier and more labored.

When a virus that can cause croup moves through a community, only some childrenwill develop croup. Most children will have symptoms of a cold or laryngitis,such as congestion, cough, hoarseness, orsore throat.

What are the causes and risks of the infection?

The parainfluenza virus is a family of viruses that accounts for 75% of casesof croup.Croup generally affects young children between 3 months and 5 years of age.Boys are affected more often than girls. About 15% of children with croup havea family history of croup. Some children have repeated episodes of croup.

Symptoms & Signs

What are the signs and symptoms of the infection?

Croup has a characteristic cough that sounds like a barking seal. This cough iswhat sets croup apart from other upper respiratory infections. Croup oftenbegins abruptly, most often in the middle of the night. Typically, a youngchild will have some cold symptoms but will seem okay when put to bed. Theparents are awakened in the middle of the night by the barking sound of thecroupy cough. This often occurs in spasms and may even cause the child tovomit. The child often feels that he or she cannot breathe.

Often the croupy cough is accompanied by a noise called stridor. This noiseis made when the child is breathing in, or inhaling. Stridor is actually a moreworrisome symptom than the cough because it means that the airway has narrowedsignificantly. This is especially true if the child has stridor when he or sheis at rest and is not upset or crying.

A child with croup may or may not have a fever.

The major risk of croup is that the child’s upper airway may swell so much thatthe child may not be able to breathe well enough. This is called respiratoryfailure. As the diameter of the airway becomes more narrowed, the resistance tothe flow of air increases. The child must exert more and more energy to supplyenough air to his or her lungs. If the work of breathing is not somehowrelieved, the child may become exhausted, go into a coma, and die. However, themajority of cases of croup do notreach this level.

Diagnosis & Tests

How is the infection diagnosed?

Croup is a clinical diagnosis. This means that it is diagnosed by observing acharacteristic set of symptoms and physical signs. At times, an X-ray exam ofthe upper airway can help show where and how much the airway is narrowed.

Prevention & Expectations

What can be done to prevent the infection?

Croup is difficult to prevent. The viruses that cause it are common, especiallyin the winter months. Most young children are not immune to these viruses, andeffective vaccines to them are not currently available. One exception is thevaccine for the influenza virus, which accounts for only a small percentage ofcroup cases.

There are a few things that can be done to help prevent croup.Breast-feeding provides some protection to infants against these commoninfections. This is probably through the transmission of maternal antibodies inthe breast milk.Also, avoiding tobacco smokemay lessen the risk of infants and young children getting respiratoryinfections.

Children in day care or preschool have greater exposure to theseviruses.There is no solid evidence that multiple or large doses of vitaminsprevent respiratory virus infections.

What are the long-term effects of the infection?

Croup usually is a short-term illness without long-term effects. For somechildren it can be a recurrent illness. Sometimes, a child with severe croupneeds to have abreathing tube inserted, which is known as endotracheal intubation. Occasionally, thehealthcare provider may need to cut a hole in the trachea below the voice boxto insert a tube for breathing, called a tracheostomy. This may lead to scarring of the trachea orvocal cords, which in turn, could affect the quality of the voice or narrow theairway.

What are the risks to others?

The viruses that cause croup are spread from person to person bycoughing or sneezing. However, only some children will develop croup when theyare exposed to these viruses.

Treatment & Monitoring

What are the treatments for the infection?

Since croup is usually caused by a viral infection, antibiotics are not helpfulin treating the infection. Relieving the swelling and respiratory distress aremost helpful.

  • For milder cases, a cool mist vaporizer should be placed near the child’sbed. This may helpreduce the cough and airway irritation.
  • For the child who awakens at night coughing and in distress, the bestthing to do is to steamup the bathroom. This can be done by running hot water in the shower. Parentsshould then have thechild sit in the bathroom breathing in the steam. Parents should stay with thechild until he or shebecomes calm.
  • Another treatment is to bundle the child up and sit outside in the coldnight air for a while. This seems to relieve the airway swelling and ease thechild’s distress.
  • Once a child has settled down, he or she should be put back to bed witha vaporizer near the bed.
  • The child should have some relief from the above measures in about 10 to 15minutes. If he or she is experiencing an alarming degree of respiratorydistress, the emergency medicalsystem should be contacted.

    Emergency room treatment usually consists of giving the child oxygen, a special form ofepinephrine that is inhaled, and possibly an injection of a steroid calleddexamethasone. If the child does not respond to these measures, he or she willbe admitted to the hospital.

    Once admitted, the child is usually placed in a mist tent with added oxygen.Children will then have their blood oxygen saturation level monitored. This isthe amount of oxygen that is carried in the child’s bloodstream. The child willbe given frequent doses of the inhaled form of epinephrine and will be watchedvery closely for any changes in breathing. In rare cases, a child may need to have abreathing tube inserted. This provides an adequate airway for several daysuntil the airway swelling goes down.

    What are the side effects of the treatments?

    Epinephrine can cause a temporary rapid heartbeat. A singleinjection of dexamethasone does not have any significant side effects. A childwho requires intubation could have some vocal cord damage or airway scarring.This may be temporary or permanent.

    What happens after treatment for the infection?

    There is no special treatment needed after thechild recovers from an episode of croup.

    How is the infection monitored?

    Younger children with a tendency to develop croup should be watched closely forearly signs of croup whenever they develop signs and symptoms of an upperrespiratory infection. Any new or worsening symptoms should be reported to thehealthcare provider.

    Article type: xmedgeneral