Bronchiolitis

• Bronchiolitis is a viral illness seen most commonly during the winter season.
• Bronchiolitis is caused by many viruses. The most common viral trigger is the respiratory syncytial virus (RSV).
• Symptoms of bronchiolitis include nasal congestion and moderate non-purulent (doesn't contain pus) nasal discharge associated with pulmonary distress that may range from mild to severe.
• Bronchiolitis is diagnosed based on the person's signs and symptoms, age, season of the year, findings on physical exam, assessment of the patient's blood oxygenation, and a nasal swab to determine the specific viral cause.
• Bronchiolitis is generally a self-limited disease and can be treated at home. Most children do not require medications; however, high-risk infants and toddlers may need to be hospitalized due to respiratory distress and/or to maintain hydration.
• Bronchiolitis prevention strategies range from thorough hand washing by caregivers to rare administration of palivizumab (Synagis) to infants of selected high-risk.
• The prognosis for a person with bronchiolitis is excellent.

Bronchiolitis is a viral infection affecting both the upper respiratory region (nose, mouth and throat) and lower respiratory tract (lungs). It is an illness in which effects are most severe in children under two years of age. Bronchiolitis is most commonly seen during the winter season (November thru March in the northern hemisphere).

Since the terms "bronchiolitis" and "bronchitis" are very similar, there may be confusion regarding each diagnosis. The difference between the two terms depends upon the anatomical area of the lungs that is infected.

• The bronchioles are very small and delicate airways that lead directly to the alveoli.
• Alveoli are the microscopic "cul de sacs" of the lung tree.
• The alveoli are where the exchange of oxygen and carbon dioxide occurs.
• Bronchi are much larger "pipes" which make up the first two to three branches of the lungs immediately after the trachea (windpipe).
• Bronchiolitis is an infant to early childhood illness.
• Most pediatric pulmonary specialists believe that bronchitis is never seen in this age range, but is more likely seen in teens and adults.
• Cigarette smoke exposure is a predisposing factor for both diseases.
• Both bronchiolitis and bronchitis are viral infections and do not require antibiotics.

The signs and symptoms of bronchiolitis may be broken down into those affecting the upper respiratory tract (nose, mouth and throat), and lower respiratory tract (lungs).

Upper respiratory tract symptoms of bronchiolitis include:

• Profuse watery nasal drainage
• Nasal congestion
• Possibly mild sore throat
• Middle ear pain may be caused by a viral infection.
• Fever is uncommon.

Following 2 to 3 days of these upper respiratory symptoms, lower respiratory tract symptoms develop with symptoms of

• cough,
• rapid and shallow breathing, and
• increased work of breathing and wheezing.

Young children, especially those younger than 6 months of age, are most likely to develop more severe symptoms that include:

• Bluish/grey skin discoloration (emergency treatment is required)
• Incessant cough compromising the infant's ability to guarantee adequate fluid and calorie intake
• Progressive fatigue
• Fever above 101F (38.3C) and worsening of respiratory distress (for example, retraction of muscles between the ribs or above the sternum (breast bone)
• Nasal flaring with inspiration
• Respiratory rate greater than 70 inspirations per minute and grunting with respiration
• Rarely, young infants may have episodes of apnea (cessation of breathing) associated with exhaustion due to respiratory fatigue.

Bronchiolitis caused by RVS is highly contagious. Other viral causes of bronchiolitis also are very likely to cause disease following exposure. Spread of these respiratory viruses is via sneezing and coughing causing a direct person-to-person transmission. Many of the viruses that cause RSV can survive many hours on surfaces and a person may inadvertently inoculate themselves by touching one of these areas (for example, table top, shopping cart, etc.) and then bringing their hands to the nose or mouth areas.

Many viruses have been shown to cause the characteristic symptoms associated with bronchiolitis. The most common viral trigger is the respiratory syncytial virus (RSV). Studies have shown that RSV has infected most children by two years of age, and many of these children will have moderate to severe symptoms during their illness. Unfortunately, infection with RSV does not provoke long-term immunity and thus a child may redevelop symptoms several times from infancy through adulthood. RSV is generally credited with causing about 75% of all bronchiolitis. Other viral causes of bronchiolitis include:

• rhinovirus
• influenza virus, and
• a scattering of other viruses individually causing.

Risk factors for bronchiolitis include:

• Prematurity (< 29 weeks' gestation before birth)
• Age < 12 weeks
• Chronic pulmonary diseases or anatomical defects of the airways
• Selected forms of congenital heart disease
• Immunodeficiency
• Certain neurologic disease
• Exposure to secondhand smoke
• Crowded living conditions (including daycare)
• Not being breastfed.

You should contact your child's pediatrician or be evaluated in the emergency room if your child:

• Has a bluish or grey color to their face, nails or lips (if severe: call 911 immediately)
• Is breathing very quickly (> 70 times per minute - this will generally appear twice as fast as normal)
• Is having respiratory distress - quick/shallow breathing, struggling to inhale or exhale
• Has flaring of the nostrils or retractions of the muscles between the ribs or above the breast bone
• Demonstrating progressive fatigue
• Development of a fever > 101F (38.3C)
• Inability to take in adequate fluids or is showing signs of dehydration

Bronchiolitis is generally diagnosed history and physical examination. The most common laboratory tests for children with bronchiolitis would include assessment of the child's blood oxygenation via a finger/toe sensor and a nasal swab to determine the specific viral cause (for example, RSV vs. influenza virus). This is most commonly indicated if a child is to be admitted to the hospital. A chest X-ray may be ordered if a concern for pneumonia exists.

In most instances home management of a child with bronchiolitis by parents should be all that is necessary. The foundation for care of infants and children with bronchiolitis includes

• maintaining hydration and (in toddlers) nutrition;
• ensuring appropriate pulmonary function (i.e. adequate oxygenation; and
• close monitoring for worsening of disease progression or the development of complications (for example, pneumonia, sleep apnea, etc.).

Until 2014 a mainstay of management of bronchiolitis involved the administration of inhaled bronchodilators. Evaluation of several agents demonstrated a potential slight improvement of respiratory distress symptoms but no long-term benefits (for example, duration of symptoms, shortening of the need for supplemental oxygen, etc.). Because there are children who have asthma exacerbations during the bronchiolitis season, some centers will provide a single inhalation bronchodilator therapy treatment. Should a substantial improvement be demonstrated, a consideration of further similar therapy can be considered. Children who do not demonstrate such an improvement need no further inhaled bronchodilators. Chest physiotherapy has not been demonstrated to be of benefit for pulmonary symptoms and is thus not recommended.

Oral bronchodilators and oral/IV/intramuscular administration of steroids provide no benefit for routine bronchiolitis therapy and should not be administered.

In very young infants (< 6 months old) or those with underlying health issues, observation and management in a hospital setting may be needed. These patients will commonly receive supplemental oxygen via nasal cannula, monitoring of blood oxygen saturation, and in selected circumstances monitoring of blood carbon dioxide (CO2) levels, maintaining appropriate hydration status.

Respiratory rates > 70 per minute may require either nasal gastric tube utilization or IV fluid administration due to changes of choking and pulmonary aspiration due to the child's rapid respiratory rate or work of breathing.

In order for a patient to be discharged from the hospital they must meet the following criteria.

• Have an appropriate respiratory rate
• An improvement in respiratory distress and normal oxygenation without supplementation
• Adequate oral intake and maintaining good hydration
• Parents who are confident in their ability to monitor their infant once provided with written guidelines prior to hospital discharge.

Because bronchiolitis is caused by a virus no antibiotics are necessary to treat it.

• While bronchiolitis is highly contagious, frequent hand washing will help lessen the exposure frequency.
• Breastfeeding and avoiding secondhand smoke also will benefit in the prevention of bronchiolitis and as other respiratory and intestinal illnesses.
• A medication called palivizumab (Synagis) acts by boosting a patient's immune system against RSV. Palivizumab is injected into the infant's leg muscle on a monthly basis during the RSV season. It has a restricted use profile that includes: moderate prematurity (< 29 weeks gestational age), chronic lung disease and/or pulmonary anatomical defects, certain types of congenital heart disease, and immune compromised children.
• Annual influenza vaccination for all infants 6 months of age and older will lessen this other major cause of bronchiolitis. Those who provide babysitting and daycare should also be immunized against influenza.