Bronchiolitis is a lower respiratory tract infection that occurs in children younger than two years old. Bronchiolitis is caused by viruses that trigger inflammation of the small airways (bronchioles)

The inflammation partially or completely blocks the airways, which causes wheezing (a whistling sound heard as the child breathes out). This means that less oxygen enters the lungs, potentially causing a decrease in the level of oxygen in the blood.

Bronchiolitis is common in infants and young children and is one of the leading reasons for hospitalization in this age group. Treatment includes measures to ensure that the child consumes enough fluids and can breathe without significant difficulty. Most children begin to improve a few days after first developing breathing difficulties, but coughing and wheezing may last for a week or longer. Bronchiolitis can cause serious illness in some children. Infants who are very young, born early, have lung or heart disease, or have difficulty fighting infections or handling oral secretions are more likely to have severe disease with bronchiolitis. It is important to be aware of the signs and symptoms that require evaluation and treatment.

Bronchiolitis is caused by viruses.

●Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis. However, many other viruses that cause colds in older children and adults can cause bronchiolitis in infants. Examples include rhinovirus (the common cold virus), influenza, COVID-19, and parainfluenza virus. Some children can be infected with more than one virus at the same time.

●RSV outbreaks usually occur from October to April with a peak in December, January, or February, the seasonal outbreaks usually are associated with the rainy season.

●RSV infection can happen at any age. For children, the risk of having severe symptoms is greatest the first time the child is infected with the virus, particularly if they are infected during infancy. Virtually everyone will have been infected with RSV by the age of three years, and reinfection is common throughout life.

RSV infections are common in children older than two years, but they typically manifest as a bad cold of flu-like illness at this age; breathing difficulties due to RSV are uncommon in children >2 years old unless they have other health problems, such as asthma.

●Bronchiolitis usually develops following one to three days of common cold symptoms, including the following:

•Nasal congestion and discharge

•A mild cough

•Fever (temperature higher than 100.4°F or 38°C) –

•Decreased appetite

●As the infection progresses and the lower airways are affected, other symptoms may develop, including:

•Breathing rapidly (60 to 80 times per minute) or with mild to severe difficulty

•Wheezing, which usually lasts approximately seven days

•Persistent coughing, which may last for 14 or more days

•Difficulty feeding related to nasal congestion and rapid breathing, which can result in dehydration

●Signs of severe bronchiolitis include:

•Retractions (sucking in of the skin around the ribs and the base of the throat)

•Nasal flaring (when the nostrils widen during breathing)

•Grunting

•Cyanosis (blue-tinged skin), which may first be noticed in the finger- and toenails; ear lobes; tip of the nose, lips, or tongue; and/or inside of the cheek

•Very rapid breathing and/or working hard to breath

•Appearing to tire out or not responding appropriately

•Apnea (a pause in breathing for more than 15 or 20 seconds), which may be the first sign of bronchiolitis in infants born prematurely and infants who are younger than two months

An infant or child with any of these severe signs of symptoms needs immediate medical attention.

Respiratory syncytial virus (RSV) is transmitted (spread) through droplets that contain viral particles; these are exhaled into the air when an infected person breathes, talks, coughs, or sneezes. These droplets can be carried on the hands, where they survive and can spread infection for several hours. If a person with RSV on their hands touches a child's eye, nose, or mouth, the virus can infect the child. Adults infected with RSV can easily transmit the virus to children or other adults. This is also true for other viruses that cause bronchiolitis.

Anyone in contact with infants or young children should wash their hands regularly or use an alcohol-based hand sanitizer if soap and water are not available

A child with bronchiolitis should be kept away from other infants and anyone else who is susceptible to severe respiratory infection (e.g.: people with chronic heart or lung diseases or a weakened immune system) until their symptoms have resolved.

Diagnosis of bronchiolitis is based upon a history and physical examination. Blood tests and X-rays are not usually necessary in infants and children with mild symptoms. However, these tests may be performed if the symptoms are severe or if there is concern that the symptoms might be due to another cause, such as pneumonia. Tests are available that can rapidly detect RSV and other viruses that cause bronchiolitis.

Emergency care — Parents/caregivers should seek medical attention if the child seems to be worsening.

Urgent medical attention should be sought if any of the following occur:

●If the infant or child is grunting or has severe retractions (sucking in of the skin around the ribs and the base of the throat)

●If the infant or child appears to be tiring or is not responding appropriately

●If the infant or child stops breathing or has pauses in breathing lasting more than 15 to 20 seconds

●If the infant or child appears cyanotic (blue-colored skin)

If your child has any of these symptoms, or if they are worsening, call emergency medical services, dial 9-1-1.

Severe bronchiolitis should be evaluated in an emergency department or clinic capable of handling urgent respiratory illnesses in children. This is a life-threatening illness, and treatment should not be delayed for any reason.

There is no treatment that can get rid of bronchiolitis, so treatment is aimed at relieving symptoms until the infection resolves. Treatment at home usually includes making sure the child drinks enough and using Saline nose drops (or bulb suctioning for infants) to keep the nose clear.

Monitoring — Monitoring at home involves observing the child periodically for any of the following signs of worsening illness:

●Rapid breathing

●Worsening chest retractions

●Nasal flaring

●Cyanosis

●Decreased ability to feed

●Decreased urine output

Contact the child's health care provider to determine if and when an office visit is needed or if there are any other questions or concerns.

If your child has a fever and/or is uncomfortable, you can give Acetaminophen (sample brand name: Tylenol) or, if the infant is six months or older, Ibuprofen (sample brand names: Advil, Motrin). Aspirin should not be given to any child under age 18 years. If your child has a fever, speak with their health care provider about when and how to treat it or if they need to be seen in the office.

Saline nose drops or spray might help with congestion and runny nose. For infants, you can try saline nose drops to thin the mucus, followed by bulb suction to temporarily remove nasal secretions.

Encourage your child to drink enough fluids to stay hydrated; it is not necessary to drink more fluids than normal. Children often have a reduced appetite and may eat less than usual. If an infant or child completely refuses to eat or drink for a prolonged period, urinates less often than normal, or has vomiting episodes with cough, contact a health care provider.

Avoid exposure to smoking: Smoking in the home or around the child should be avoided because it can worsen a child's breathing symptoms. Exposure to secondhand smoke can also lead to other health problems in children.

Other therapies, such as antibiotics, cough medicines, and decongestants, are not recommended. Cough medicines and decongestants have not been proven to be helpful and they are unsafe for use in young children. Coughing is one way for the body to clear the lungs and normally does not need to be treated. As the lungs heal, the coughing caused by the virus resolves.

Antibiotics are not effective in treating bronchiolitis because the illness is caused by viruses (antibiotics are only effective against infections caused by bacteria). However, antibiotics may be necessary if the child also has a bacterial infection, such as an ear infection (common) or bacterial pneumonia (uncommon).

Sometimes, keeping the child's head elevated can make it easier for them to breathe. A child over the age of one year may be propped up in bed with an extra pillow. Pillows should not be used with infants younger than one year.

A small minority of infants and children with bronchiolitis (<5 percent) require monitoring and treatment in a hospital. Most children receive monitoring of vital signs and supportive care, including oxygen therapy and intravenous (IV) fluids, if necessary. Other treatments are individualized, based upon the child's needs and response to therapy.

Because the viruses that cause bronchiolitis are contagious, precautions must be taken to prevent spreading the virus to other patients and/or children. Members of the health care team should wash their hands before and after entering the room. In addition, depending on the specific virus identified, they may wear personal protective equipment (gown, gloves, mask) when in the room. Parents or primary caregivers may visit (and stay with the child), but siblings and friends should not. Toys, books, games, and other activities can be brought to the child's room. All visitors must wash their hands before and after leaving the room.

Most infants and children can continue to eat, breastfeed, or drink normally while in the hospital. If the child is unable or unwilling to eat or drink adequately, either due to lack of interest or because their rapid breathing makes it difficult to feed, they may need to receive fluids through an IV.

Infants and children who are hospitalized for management of bronchiolitis often require breathing treatments, which may include:

●Oxygen therapy – This is usually given by placing a tube (called a nasal cannula) under a child's nose or by placing a face mask over the nose and mouth. For children with more severe symptoms, many hospitals use a form of oxygen therapy that delivers oxygen through a nasal cannula at a high rate, which may help the infant breath more comfortably. This is often referred to as "high flow."

The child's oxygen level is monitored and as the illness improves, the oxygen therapy is gradually reduced. The goal is to slowly reduce and then discontinue supplemental oxygen when the child is ready.

●Nebulizer treatments – Nebulizer treatments are medications that are given as a fine mist that is inhaled through a mask or mouthpiece. Nebulizer treatments are not used as a routine for children with bronchiolitis, but they are sometimes used in infants and children with more severe symptoms. The most commonly used medication is Albuterol. It is typically given as a trial initially. If the child does not respond, it is not continued. However, if the child has a good response to the medication, it may be continued. In addition, nebulized Saline treatments are sometimes used in children with bronchiolitis to help clear the nasal and airway secretions.

●Intubation – Very rarely, a severely ill infant or child may be unable to breathe adequately on their own, or they may stop breathing due to bronchiolitis. If this happens, a breathing tube (endotracheal tube) may be inserted into the mouth and throat. This is connected to a machine (called a ventilator) that breathes for the child at a regular rate. The use of an endotracheal tube and ventilator is a temporary measure that is discontinued when the child improves.

Most children who require hospitalization are well enough to return home within three to four days. Children who require a machine to help them breathe usually need to stay in the hospital for a longer period before they are ready to go home.

Most children with bronchiolitis who are otherwise healthy begin to improve within two to five days. However, coughing and wheezing may persist in some infants for a week or longer, and it may take as long as four weeks for the child to return to their "normal" self. Recovery may take longer in younger infants and those with underlying medical problems (e.g., prematurity, other lung diseases). The child should be kept out of day care or school until the fever and runny nose have resolved (i.e., the time during which they are most contagious).

Several vaccines are available that help prevent some of the causes of bronchiolitis:

●RSV – There are two options for preventing severe RSV infections in young infants:

•Vaccination in pregnancy – A vaccine for RSV is available for pregnant people. It is given in the third trimester of pregnancyif the due date is just prior to or during RSV season. Vaccination during pregnancy reduces the risk of severe RSV infections in the newborn during the first few months after birth.

•Antibody injection – Another option for preventing severe RSV infections in infants is a treatment called a "monoclonal antibody" injection. Nirsevimab [brand name: Beyfortus]) is given as a single injection to the infant. Nirsevimab is recommended for infants whose mothers did not receive the RSV vaccine during pregnancy. If the infant is born during or just before RSV season, nirsevimab may be given to the newborn before discharge from the birth hospital. If the infant is born outside of the RSV season, nirsevimab is given before the start of the next RSV season, provided that the infant is <8 months old at that time. Infants who are at high risk for severe RSV infection may receive a second dose of nirsevimab if they are ≤19 months old at the start of their second RSV season.

In the United States, Nirsevimab may not be available in all health care settings during the 2023-2024 season. If supply is limited, your child's health care provider will talk to you about your options. In some cases, an older antibody medication called Palivizumab (brand name: Synagis) can be used instead. Because palivizumab does not last as long, it is given as monthly injections rather than once per season. Both Nirsevimab and Palivizumab have a low risk of serious side effects.

●Influenza – A yearly vaccination for influenza virus is recommended for everyone older than six months, especially for household contacts of children younger than five years, and out-of-home caregivers of children younger than five years.

●COVID-19 – COVID-19 vaccination is recommended for everyone six months and older.

There are several other ways to prevent severe bronchiolitis:

●Avoid smoking around the child, as this increases the risk of respiratory illness.

●Wash hands frequently with soap and water, especially before touching an infant. Hands should ideally be wet with water and plain or antimicrobial soap and rubbed together for at least 20 seconds. Hands should be rinsed thoroughly and dried with a single-use towel. If you cannot wash your hands in a sink, use a gel with at least 60 percent alcohol.

●Stay away from other adults and children with upper respiratory infection. Keep infants or children home from school or day care when they are sick.

There is a relationship between bronchiolitis during infancy and later development of asthma.

Compared with infants who never had bronchiolitis, infants hospitalized for bronchiolitis are three to four times more likely to be diagnosed with asthma or recurrent wheezing during the first 10 years of life. It is unclear if having bronchiolitis in infancy is what causes the asthma in these children. Many experts believe that it is more likely that there are underlying risk factors (e.g., genetic factors and environmental exposures such as cigarette smoke) that contribute to both the risk of wheezing in infancy (bronchiolitis) and wheezing later in childhood (asthma).

The first time a young child develops wheezing, it can be difficult to know if it is caused by bronchiolitis or asthma. Most cases of first-time wheezing are caused by a virus. A history of recurrent wheezing episodes and a family or personal history of asthma, nasal allergies, or eczema help to support a diagnosis of asthma. Viruses frequently trigger asthma attacks in children with asthma.

After developing bronchiolitis, some infants will have recurrent episodes of wheezing during childhood. These wheezing episodes are triggered by viruses and may respond to the same treatments used in children with asthma.

WHEN TO SEEK HELP

If at any time, a child develops features of worsening or severe bronchiolitis, the parent should seek immediate medical attention. This includes:

●Difficulty breathing or working hard to breath

●Pale or blue-tinged (cyanotic) skin

●Severe coughing spells

●Severe sucking in of the skin around the ribs and base of the throat (retractions) with breathing

●If the child stops breathing

Do not attempt to drive your child to the hospital yourself if the child is severely agitated, cyanotic, struggling to breathe, stops breathing, or is excessively drowsy (lethargic). In this situation, call emergency medical services (dial 9-1-1).

Call the child's doctor or nurse if:

●The child has a fever (temperature higher than 100.4°F or 38°C), particularly for infants who are younger than three months

●The child has signs or symptoms of bronchiolitis

●The child has difficulty feeding or has fewer wet diapers than usual

●You have any questions or concerns about the child's condition