- acute laryngotracheobronchitis
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 the tissues around the larynx and vocal cords. The diameter of the upper airway in young children is narrow to begin with, so this swelling further reduces the size of the airway. This makes breathing noisier and more labored.
When a virus that can cause croup moves through a community, not all children who become infected will develop croup. Most children will have symptoms of a cold or laryngitis, such as congestion, cough, hoarseness, or sore throat.
What are the causes and risks of the infection?
The parainfluenza virus is a family of viruses that accounts for 75% of cases of 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 have a family history of croup. Some children have repeated episodes.
What can be done to prevent the infection?
Croup is difficult to prevent. The viruses that cause it are common, especially in the winter months. Most young children are not immune to these viruses, and effective vaccines to them are not currently available. The one exception is the vaccine for the influenza virus, which accounts for only a small percentage of croup cases.
A few things can be done to help prevent croup. Breast-feeding provides some protection to infants against these common viruses, probably through the transmission of maternal antibodies in the breast milk. Also, avoiding tobacco smoke may reduce the risk of respiratory infections in infants and young children
Children in day care or preschool have greater exposure to these viruses. There is no solid evidence that multiple or large doses of vitamins prevent respiratory virus infections.
How is the infection diagnosed?
Croup is a clinical diagnosis. This means that it is diagnosed by observing a characteristic set of symptoms and physical signs. At times, an X-ray exam of the upper airway can help show where and how much the airway is narrowed.
Long Term Effects
What are the long-term effects of the infection?
Croup usually is a short-term illness without long-term effects. For some children it can be a recurrent illness. Sometimes, a child with severe croup needs to have a breathing tube inserted, which is known as endotracheal intubation.
Very occasionally, the healthcare professional may need to cut a hole in the trachea below the voice box to insert a tube for breathing, called a tracheostomy. This may lead to scarring of the trachea or vocal cords, which in turn, could affect the quality of the voice or narrow the airway.
What are the risks to others?
The viruses that cause croup are spread from person to person by coughing or sneezing. However, only some children will develop croup when they are exposed to these viruses.
What are the treatments for the infection?
Since croup is usually caused by a viral infection, antibiotics are not helpful in treating the infection. Relieving the swelling and respiratory distress are most helpful.
- For milder cases, a cool mist vaporizer should be placed near the child's bed. This may help reduce the cough and airway irritation.
- For the child who awakens at night coughing and in distress, the best thing to do is to steam up the bathroom. This can be done by running hot water in the shower. Parents should then have the child sit in the bathroom breathing in the steam. Parents should stay with the child until he or she becomes calm.
- Another treatment is to bundle the child up and sit outside in the cool night air for a while. This seems to relieve the airway swelling and ease the child's distress.
- Once a child has settled down, he or she should be put back to bed with a vaporizer near the bed.
The child should have some relief from the above measures in about 10 to 15 minutes. If he or she is experiencing an alarming degree of respiratory distress, the emergency medical system should be contacted.
Emergency room treatment usually consists of giving the child oxygen, a special form of epinephrine that is inhaled, and possibly an injection of a steroid called dexamethasone. If the child does not respond to these measures, he or she will be 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 is the amount of oxygen that is carried in the child's bloodstream. The child will be given frequent doses of the inhaled form of epinephrine and will be watched very closely for any changes in breathing. In rare cases, a child may need to have a breathing tube inserted. This provides an adequate airway for several days until the airway swelling goes down.
What are the side effects of the treatments?
Epinephrine can cause a temporary rapid heartbeat. A single injection of dexamethasone does not have any significant side effects. A child who 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 the child recovers from an episode of croup.
How is the infection monitored?
Younger children with a tendency to develop croup should be watched closely for early signs of croup whenever they develop signs and symptoms of an upper respiratory infection. Any new or worsening symptoms should be reported to the healthcare professional.