What is Bronchiolitis (obliterating and viral)? See the symptoms


What is bronchiolitis?

Bronchiolitis is a common seasonal viral infection in babies, characterized by symptoms similar to colds, swelling and accumulation of mucus in the bronchioles. It is usually caused by common viruses and resolves easily in a few days, but may, in some cases, require medical assistance.

During breathing, air enters the nostrils, passes through the pharynx, larynx, trachea, bronchi and, finally, the bronchioles, which are the final portion of the lower respiratory tract before the alveoli, a structure where the exchange of oxygen gas with carbon dioxide occurs . In the respiratory tree, the most distant portions of the bronchi are getting thinner and, for this reason, the bronchioles are almost microscopic structures, less than 1 millimeter in diameter.

The disease happens when there is an inflammatory process in the bronchioles, usually caused by some virus, in which the walls of the structure become swollen and make breathing difficult. In these cases, there is often an accumulation of mucus inside the bronchioles, preventing the passage of air.

It is more common in infants, especially between 2 and 6 months , although many children may have it by 2 years of age. In adults, there is a type of bronchiolitis called bronchiolitis obliterans, which is caused not by a virus, but by scarring in that structure.

Such a condition is not usually serious, however, there are cases that may require hospitalization, especially in babies younger than 6 months. When treated, it has an excellent prognosis, although it is related to later respiratory complications.

Types of bronchiolite

Bronquiolite viral

The main type of bronchiolitis is viral, which occurs, most of the time, in babies under 2 years old. It is caused by the presence of viruses in the lower respiratory tract, more precisely in the bronchioles, small passages that lead the air to the alveoli, the final portion of the respiratory system.

Bronquiolite obliterante

It is a rare and dangerous type of bronchiolitis, which affects adults instead of babies. In these cases, the blockage of the lower respiratory tract is caused by the presence of scarring in the bronchioles, and not by swelling or accumulation of mucus. It is not caused only by a viral infection, but by a combination of several factors.

Causes of bronchiolitis

Bronchiolitis is usually caused by viral infections in the respiratory tract. Due to the virus’s ability to rapidly reproduce, these infections can begin in the upper respiratory tract and spread to the lower, which is when it comes into contact with the bronchi and bronchioles. Know more:

Respiratory syncytial virus (RSV)

Most cases of bronchiolitis are caused by RSV, a virus found in abundance worldwide, responsible for several common colds.


It is a virus that affects the mucous membranes, responsible for about 10% of respiratory infections in children.

Other viruses

There is evidence that bronchiolitis can also be caused by other common viruses, such as rhinovirus, metapneumovirus (MVP), influenza, parainfluenza, enterovirus and bocavirus.

In addition, episodes of acute bronchiolitis can be caused by the presence of more than one of these viruses in the child, generating a more serious clinical situation.

The condition is known to affect mainly young children for two reasons:

  1. Due to the developing immune system, viruses can easily cause a more severe clinical picture;
  2. Babies’ bodies are smaller and, therefore, the movement of viruses to bronchioles is facilitated. So much so that, in general, children older than 2 years who are infected by viruses in the respiratory tract do not develop bronchiolitis, and the infection is limited only to the upper airways.

The presence of viruses in the bronchioles causes infection and swelling in them, hindering the passage of air, and the accumulation of mucus in the airways aggravates the situation. Thus, symptoms similar to those of asthma appear .

Causes of bronchiolitis obliterans

As stated earlier, bronchiolitis obliterans does not occur only due to viral infection, since other factors participate in the development of the disease. The cause of this type of bronchiolitis is not known for certain, but some factors related to it are:

  • Vapors from chemical agents such as chlorine, ammonia and bleach;
  • Respiratory infections;
  • Adverse reactions to medications;
  • Inhalation of irritating substances, such as cigarette smoke.

Risk factors

There are some risk factors for some children to develop bronchiolitis, the main one being young age . This is because, the younger the child is, the greater the chances of developing the disease.

Low weight and lack of breastfeeding also count, as adequate nutrition is essential for the development of the immune system, which is already underdeveloped in young children.

Other factors are:

  • Premature birth;
  • Passive smoke;
  • Attend environments other than the home itself, such as a daycare center;
  • Have siblings who frequent other spaces and can bring the virus home;
  • Living with many people;
  • Cold environments, as people usually close doors and windows, preventing air circulation, which helps to spread the virus.

Transmission: Is bronchiolitis contagious?

The transmission of bronchiolitis occurs along with that of common colds and flu , because it is caused by the same viruses.

These viruses are transmitted, mainly, through direct contact with mucous membranes, where they have a high capacity for reproduction, or with droplets of saliva spread through the air.

Such microorganisms can also survive long periods of time on surfaces such as clothes, toys, objects on the table, tissues and even on the skin. Contact with these contaminated surfaces can lead to infection if the necessary measures are not taken, such as washing your hands frequently, for example.

In the case of babies, the infection usually happens when they attend a daycare center, live directly or indirectly with many people, share toys with other children, or when infected adults do not take proper care when approaching. This is because these conditions favor contact with contaminated individuals or surfaces.

It must be remembered that RSV is an extremely common virus and is worldwide, so that all children come into contact with it before they are 3 years old. While some children are affected with simple colds, others develop more severe conditions that require hospitalization.

RSV infection does not make the child immune to the virus, and there may be new infections in the future. However, these recurrences are usually milder, especially in older children.

Groups of risk

There are babies who are at higher risk for contracting bronchiolitis. Are they:

  • Premature babies, because they have a weaker immune system than babies with normal births;
  • With heart or lung problems, because problems in these systems facilitate the contraction of diseases;
  • With a deficiency in the immune system, since the production of antibodies may be limited and unable to fight the virus.

When observing a picture of bronchiolitis in these children, medical assistance is essential, since the probability of a more severe clinical picture is high.

Bronchiolitis symptoms

The first symptoms of bronchiolitis are those commonly related to a common cold : runny nose, nasal congestion, sneezing, cough and low-intensity fever , not always present.

Over the course of the days, the child may start to present:

  • Rapid and shallow breathing;
  • Intensification of cold symptoms;
  • Irritability, peevishness and tiredness;
  • Decreased appetite;
  • Difficulty falling asleep.

Some children may also experience apnea, a temporary respiratory arrest that most commonly occurs during sleep. This occurs mainly in premature babies or those born underweight.

How to differentiate bronchiolitis from a common cold?

At first, it may be difficult to know what the condition is about, as the symptoms are very similar to those of a common cold. However, one can pay attention to the intensity of the symptoms, which tends to be greater in cases of bronchiolitis.

Thus, to resolve the doubt and receive a correct diagnosis, a pediatrician should be sought when the child shows the following signs:

  • Exaggerated opening of the nostrils;
  • Great expansion of the rib cage with each breath;
  • Contraction of the abdominal muscles to breathe;
  • Skin pulled or stretched in the following areas: between the ribs, above the collarbone or below the rib cage;
  • Wheezing when breathing, usually like the sound of a whistle;
  • Cough that doesn’t go away;
  • Blue lips and nails (cyanosis).

How is the diagnosis of bronchiolitis made?

The diagnosis of bronchiolitis is, in most cases, clinical, and can be made by a pediatrician or general practitioner. The procedure is based on the following conditions:

  • Age between 0 and 2 years;
  • Acute onset of cold symptoms, such as runny nose, cough, sneezing, with or without the presence of fever;
  • Tachypnea (accelerated breathing), with or without respiratory failure;
  • Clinical signs of lower airway obstructions, such as wheezing (wheezing) and prolonged expiration.

For patients seen in hospitals, an oximetry can be performed, an examination that promotes the measurement of the levels of oxygen carried by the blood.

In some cases, a chest X-ray may also be requested, when there is diagnostic doubt, when the disease evolves differently from the standard or for patients admitted to the ICU.

The criteria for admitting a patient to hospital are:

  • Clinical signs of respiratory failure;
  • Blood oxygen rate equal to or less than 92% (hypoxemia);
  • Lethargy;
  • Inability to drink liquids;
  • High-risk patient (underweight, premature, immunosuppressed, among others).

Is bronchiolitis curable? What is the treatment?

Fortunately, bronchiolitis is curable and, in most cases, resolves without the need for clinical treatment. Still, there are more serious cases that need assistance. Check out some treatments that can be indicated for bronchiolitis:

Home treatment

When there are no signs of respiratory distress, treatment can be done at home, by controlling fever, rest and hydration with a bottle or breast milk. In addition, in older children, meals can be split up to avoid fatigue when eating.

The doctor may recommend saline for nasal clearance, since decongestants should not be administered to young children.


Clinical treatment

In more complicated cases, the child may be hospitalized in order to receive more specific care at the hospital. Some of these precautions are:

  • Hydration: Through serum intravenously;
  • Oxygen therapy: Medical application of oxygen, usually by inhalation;
  • Respiratory physiotherapy: Performing breathing exercises that help to eliminate secretions.

Medications for bronchiolite

There are not many drugs that promote significant improvement in bronchiolitis. Thus, drug treatment is only done in extreme cases and is usually administered within a hospital. Understand:


Most patients do not benefit from treatment with bronchodilators, and in only a few cases, epinephrine administration may be indicated . This treatment is only maintained when there is significant improvement after 30 minutes of the first dose.

There are no benefits to using ipratropium bromide .


Ribavirin may be indicated in patients with immunodeficiencies or with severe bronchiolitis caused by RSV . This medication should not be used in the routine treatment of patients with bronchiolitis.

For children over 1 year infected with the influenza virus, there are two situations in which oseltamivir can be indicated:

  • When the patient is at high risk of serious infection;
  • When the patient is already in a severe clinical condition.

Antibiotics should not be used unless there is evidence of a bacterial infection.

Other drugs not indicated are antihistamines, decongestants and antitussives.


NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained in this website is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

For some time after recovery, the baby may continue to hiss when breathing, a condition called recurrent post-bronchiolitis wheezing. When the wheezing returns, the child should be taken to the pediatrician, as there is often a need for medical intervention.

It is important to note that the child is not immune after bronchiolitis, and can contract the disease again until he has grown up enough.

Living with bronchiolitis

Due to the short duration of bronchiolitis (in the simplest cases), living with the condition is simple and does not require much effort, just a few basic measures for better hygiene and comfort. Understand:

  • Raise the head of the cradle or bed where the baby sleeps, as the elevation of the head helps with breathing when there is nasal congestion;
  • The use of air humidifiers may be recommended by the pediatrician, as moistening the airways makes breathing easier. However, you should always follow the device manufacturer’s recommendations and keep it always clean, as dirty devices only serve to spread microorganisms in the air;
  • Keep the baby away from agents that can make breathing difficult, such as cigarette smoke, fresh paint, burnt wood or wood, powders, among others;
  • For babies under 6 months, the pediatrician can evaluate the possibility of administering some painkiller to reduce the baby’s physical discomfort. For older babies, the pediatrician can indicate the most appropriate treatment for the child.


When treated, bronchiolitis has no serious complications.

Some research argues that babies infected by the viruses that cause bronchiolitis are more likely to develop asthma in the future, but it has not been discovered whether there is a causal relationship between these two conditions.

If left untreated, severe cases of bronchiolitis contribute to the development of pneumonia , which must then be treated separately. In addition, the disease can lead the child to respiratory failure, in which he will only be able to breathe with the help of devices.

How to prevent bronchiolite?

The best way to prevent bronchiolitis is to properly vaccinate young babies as soon as they reach the age required for each vaccine. The vaccine against the influenza virus, for example, is released to babies from 6 months.

In addition, the baby should be prevented from coming into contact with cigarette smoke, as this makes him more susceptible to contracting viruses.

Parents and responsible adults should always keep their hands clean when in contact with the child. Washing your hands with soap (normal or antibacterial) prevents viruses and bacteria present on the skin from coming into contact with the baby. Gel alcohol is also an effective measure.

Hospitalized patients should be kept in separate rooms from others, and medical staff should take contact precautions, such as wearing a disposable mask , aprons and gloves, and wash their hands vigorously after contact with any patient.

Pediatricians may recommend the prophylactic use of oseltamivir for whom vaccination is contraindicated. This administration must be done according to what the pediatrician indicates, and cannot be done without medical supervision.

Bronchiolitis is a condition that can happen to any baby, at any time, and it is important that the mother or guardians pay attention to the signs so that the child has the necessary medical assistance as soon as possible.

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