Bronchiolitis in children is primarily caused by viral infections that lead to inflammation and swelling of the small airways in the lungs, called bronchioles. The most common culprit is the Respiratory Syncytial Virus (RSV), which is responsible for the majority of bronchiolitis cases in infants and young children under two years old. RSV infects the lining of the bronchioles, causing them to become inflamed and filled with mucus, which narrows the airways and makes breathing difficult.
The infection usually starts with symptoms similar to a common cold, such as a runny nose, mild cough, and sometimes a low-grade fever. However, as the virus spreads deeper into the lungs, it causes swelling and mucus buildup in the bronchioles, leading to wheezing, coughing, and trouble breathing. This progression can happen quickly, especially in infants younger than six months, whose airways are very small and more easily obstructed.
Bronchiolitis is highly contagious and spreads through respiratory droplets when an infected person coughs or sneezes. It can also spread by touching surfaces contaminated with the virus and then touching the face, especially the nose or mouth. Because RSV and other viruses that cause bronchiolitis are so contagious, outbreaks often occur during the fall and winter months when people spend more time indoors and in close contact.
Besides RSV, other viruses can cause bronchiolitis, including rhinovirus (which causes the common cold), influenza virus, parainfluenza virus, adenovirus, and human metapneumovirus. These viruses all infect the respiratory tract and can lead to similar inflammation of the bronchioles.
Certain factors increase the risk of severe bronchiolitis in children. Premature infants, babies with underlying heart or lung conditions, children with weakened immune systems, and those with neuromuscular disorders are more vulnerable to serious illness. In these children, the inflammation and mucus buildup can severely restrict airflow, sometimes requiring hospitalization for oxygen therapy or mechanical ventilation.
The symptoms of bronchiolitis can include:
– Runny nose and nasal congestion
– Coughing and wheezing
– Rapid or labored breathing, sometimes with flaring nostrils or chest retractions (where the skin pulls in between the ribs or under the neck during breathing)
– Difficulty feeding or decreased appetite
– Irritability or lethargy in infants
– Fever, though it may be mild or absent
In very young infants, signs like pauses in breathing (apnea), bluish skin color due to lack of oxygen, or extreme difficulty breathing are serious and require immediate medical attention.
Bronchiolitis usually resolves on its own with supportive care, such as keeping the child hydrated, managing fever, and ensuring they get enough oxygen. However, because the inflammation narrows the small airways, some children may need medical interventions to help them breathe more easily.
Preventing bronchiolitis involves minimizing exposure to the viruses that cause it. Good hand hygiene, avoiding close contact with sick individuals, and cleaning surfaces regularly can reduce the spread. For high-risk infants, there are preventive medications available that can help protect against RSV infection during peak seasons.
In summary, bronchiolitis in children is caused by viral infections—most commonly RSV—that inflame and congest the small airways in the lungs, leading to breathing difficulties. It is highly contagious and spreads easily among young children, especially during colder months. While most cases are mild, infants and children with certain risk factors may experience severe symptoms requiring medical care.
