| Chapter 11: | The Infant |   |
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Bronchiolitis
Acute bronchiolitis is a viral infection that leads to swelling, inflammation, and constriction in the bronchioles. While its consequences are gravest among infants less than six months, it presents potentially serious problems in children up to three years of age. A respiratory syncytial virus (RSV) is the primary causative agent, causing about 75% of all cases. RSV is highly contagious, and requires extreme care in hand washing and other precautions in order to prevent nosocomial outbreaks.
Clinically, the child with bronchiolitis begins with a typical upper airway infection complete with runny nose, cough, and fever that lasts 2-3 days. With the onset of bronchiolar involvement, the cough worsens, and patients under 3 years of age begin showing signs of small airway obstruction and congestions. These signs include: expiratory wheeze, tachypnea, cyanosis in severe cases, low-grade fever, possible intercostal retractions, bilateral crepitant rales, and hyperinflation. Infants older than 3 years are rarely affected to this degree.
The treatment depends on the age of the infant and severity of symptoms. Infants less than 4 months of age may require hospitalization to control intake of fluids and potential apnea. The level of distress and blood gas values determine the next step of treatment for those infants hospitalized. Older infants or those with less severe distress, apnea, and worsening blood gas values are treated with Ribavirin because of its specific antiviral activity against RSV.
While Ribavirin is not needed by all bronchiolitis patients, infants considered at high-risk benefit greatly from its administration. The medication is delivered via a special small-particle aerosol generator (SPAG), with 12-18 hours a day of treatment for at least and no more than 7 days. RCPs should take extreme care to avoid unintentionally inhaling any of the ribavirin being administered. Other treatments include aerosolized bronchodilators, Alpha-2A-interferon, immunoglobulin A, and RSV immune globulin.
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Asthma
Asthma is briefly mentioned here because it is an airway disorder in which a patient's hyperractive airways spasm and constrict, swell, and pour secretions into the lumen in response to a variety of stimuli. It is the most common pediatric lung disease, ant the most frequent cause of hospitalization in the United States. About 1 in every 12 school-age children in the U.S. have asthma, and between 3-5% of the adult population has asthma, with 50% of them acquiring it prior to age 10.
While asthma's exact etiology is not known for sure, there are several factors that precipitate acute attacks, including:
- Allergens (molds, pollens)
- Indoor irritants (dusts, second hand smoke, animal danders)
- Outdoor irritants (air pollution, smoke)
- Viral infections
- Foods
- Aspirin and related medications
- Exercise
- Emotional reactions
Asthma can be classified on the basis of the types of agents which are causative:
- Extrinsic asthma is caused by external agents such as allergies to pollens, dust and various medications.
- Intrinsic asthma is caused by internal allergens such as emotional reactions, exercise, and respiratory tract infections.
Asthmatic episodes are usually characterized by the presence of coughs, wheezing, dyspnea. They also are associated with decreased alveolar ventilation with severe bronchospasm, and prolonged expiration along with sibilant or sonorous rales.
Asthma attacks generally vary widely in severity from person to person, and episode to episode. Status asthmaticus involves prolonged periods of bronchospasm which are generally not responsive to treatment, and can even become life-threatening.
Asthma treatments require discovering what precipitates the patient's attacks, finding ways for avoiding those factors, and treating the effects of the attacks when they occur. Oxygen is nearly always indicated to treat for hypoxemia, keeping PaO2 above 55 mm Hg. Bronchospasm requires administration of aerosolized medications, usually with bronchodilators. Corticosteroids are effective prophylactics for hyperreactivity. Mechanical ventilation and psychological counseling are often also necessary.
Despite advances in treatment protocols, asthma continues to be a significant cause of respiratory distress among pediatric populations. Drug treatment is mainly focused on preventing the release of inflammatory mediators, reversing bronchospasms, and reducing inflammation in the airways. There continue to be promising research findings focusing on new longer acting medications which are designed to prevent or slow the onset of asthma.