What is bronchiolitis?
Bronchiolitis is an acute respiratory illness that primarily affects children under two years of age. It is characterized by inflammation of the bronchioles, which are small airways in the lungs that connect the bronchi to the alveoli (important parts of the respiratory system) and have a diameter smaller than the graphite of a pencil in a baby younger than six months, for example.
The blockage of the bronchiole leads to difficulty in exhaling air from the lungs and causes a wheezing sound during the passage of air through these narrowed tubes. The smaller the baby, the narrower the bronchiole, and any swelling can lead to significant obstruction.
Symptoms
The symptoms of bronchiolitis can range from mild to severe, and in some cases, the condition may require immediate medical attention. Some common symptoms of the disease include:
- Initial cold-like symptoms: may include runny nose, sneezing, mild fever, and cough
- Development of severe respiratory symptoms: rapid and shallow breathing, chest wheezing, and increased respiratory effort
- Persistent cough: rapid and shallow breathing, chest wheezing, and increased respiratory effort
Causes
Bronchiolitis is primarily caused by viral infections, with the respiratory syncytial virus (RSV) being the most common infectious agent associated with this condition. However, other respiratory viruses can also trigger cases of bronchiolitis:
- Adenovirus: can also cause bronchiolitis, especially in older children
- Rhinovirus: one of the main agents causing the common cold, can, in some cases, lead to the development of bronchiolitis
- Influenza virus (flu): can cause severe respiratory symptoms and, in some cases, result in bronchiolitis
- Metapneumovirus: can cause respiratory system infections, including bronchiolitis
Diagnosis
The diagnosis of bronchiolitis is generally based on a combination of the following factors:
- Clinical evaluation: the pulmonologist conducts a detailed clinical evaluation, which includes questions about the symptoms, recent medical history such as prematurity or previous respiratory illness in the child, and environmental risk factors like exposure to cigarette smoke and family history of bronchial asthma
- Physical examination: during the physical examination, the physician observes signs of respiratory distress, such as rapid and shallow breathing, use of accessory muscles for breathing, and chest wheezing
- Viral detection tests: especially when confirmation of the causative virus is necessary, the physician may recommend laboratory tests to identify the responsible virus, such as respiratory syncytial virus (RSV)
Treatment
The treatment of bronchiolitis is primarily supportive, as the condition is caused by viral infections and generally resolves on its own. Some approaches to assist the process include:
- Adequate hydration: especially if there are difficulties in feeding due to respiratory distress
- Respiratory monitoring: paying attention to the patient's breathing and oxygenation is essential. In some cases, supplemental oxygen may be necessary
- Use of bronchodilators (substances that promote the dilation of small airways in the lungs): especially when there is evident wheezing, the physician may prescribe bronchodilators to help patients with bronchiolitis
Prevention
The prevention of bronchiolitis largely involves measures to reduce the risk of respiratory viral infections, which are the main causes of this condition in children. Common recommendations include:
- Regular handwashing: one of the most effective ways to prevent the spread of respiratory viruses, especially through the use of hand sanitizer
- Avoiding close contact with people who have colds or the flu: this is particularly important for babies and young children, who are more vulnerable
- Preventing airborne contamination: when coughing or sneezing, it is important to cover the mouth and nose with a disposable tissue or the elbow. This helps prevent the spread of respiratory droplets in the air
- Use of hyperimmune immunoglobulin: a product containing high specific antibodies, for extreme preterm infants or preterm infants with chronic respiratory disease or congenital heart disease, this immunoglobulin is applied during the time of year with the highest transmission of RSV in the 1st and/or 2nd year of life
- RSV vaccine for pregnant women: in some countries, it is already available. By taking it, the mother produces antibodies against RSV that cross the placental barrier and provide protection against RSV after birth
References
Prefeitura de SP - Bronquiolite [Prefeitura de SP – Bronchiolitis
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