RSV
RSV is the most common cause of bronchiolitis and viral pneumonia in children under 1 year; it is also the most common cause of acute lower respiratory infections (ALRIs) among children under 3 years of age (Centers for Disease Control [CDC], 2010). Outbreaks occur annually, usually start- ing in October or November in the Western Hemisphere, and can last up to 6 months. Acute lower airway disease is more common in younger patients, and the morbidity and mortality rates are higher in infants (CDC, 2010). In recent years, it has been estimated that more than 125,000 children under 4 years of age have been hospitalized in the United States for RSV disease during the first year of life (Krilov, 2010). Preexisting lung diseases, such as chronic lung disease of prematurity, increase the likelihood of
112 Nursing Care in Pediatric Respiratory Disease
severe disease. Because there are at least three strains of RSV, reinfection is possible and can result in a more severe illness (Dakhama et al., 2009).
RSV infects older children and adults as well, causing a simple URI in otherwise normal subjects and triggering asthma symptoms in those with asthma.
RSV can be confirmed through a nasal wash or swab. Diagnosis can also be assumed through clinical symptoms and presentation. While many children are infected with RSV each year, some will have more serious symptoms requiring hospitalization and sometimes assisted ventilation.
The most serious complications facing RSV-infected patients are apnea and respiratory distress. At times, infants under 3 months of age may develop apnea first as the only sign of RSV infection. Additionally, RSV has been linked to death in a number of cases (Poets, 2008).
Infants with recurrent apnea due to RSV infection may require ventila- tion until the apnea resolves, usually within a few days. Agitation, particu- larly if not resolved by supplemental oxygen, can be an indication of respiratory insufficiency in infants. In such children, it is mandatory to assess the degree of ventilation, best done with an arterial blood gas.
Careful clinical assessment for signs of respiratory distress (nasal flaring, intercostal retractions, grunting, tachypnea, and tachycardia) and monitor- ing of pulse oximetry is essential when caring for an infant with RSV. A properly performed venous blood gas can give an indication of the degree of ventilation but is generally less accurate than an arterial blood gas.
Parainfluenza
Parainfluenza is another common cause of acute lower respiratory illness in children under 5 years (Dubois & Ray, 1999). The course of illness for parainfluenza is similar to that described above for RSV, and the manage- ment of the illness is generally the same. Parainfluenza is also a common cause of acute croup, which is discussed in Chapter 6.
Influenza
Influenza (types A and B) is a major cause of lower respiratory disease in children and can be fatal. Influenza viruses are categorized according to the type of hyaluronidase and neuraminidase they contain. (There are several of each types of enzyme resulting in the viruses being labeled HxNx.) Outbreaks generally occur in the cool winter months and spread quickly. Seasonal influenza rarely survives in the summer months.
However, the 2009 H1N1 influenza first appeared in the spring, with the pandemic waning in August of that year. The pandemic then began again that September and persisted into February of the following year.
The clinical presentation of influenza differs from that of RSV or para- influenza in that the symptoms often appear rapidly and become severe
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over the first 24 hours. Typically, fever and malaise develop first, followed by the onset of nasal congestion and cough. Although bacterial superinfec- tion can occur at anytime, a more serious viral pneumonia can be seen within the first 2 or 3 days of the illness. Such a viral pneumonia can lead to acute respiratory distress. On the other hand, the bacterial superinfec- tions are more likely to be seen 1–2 weeks after the onset of symptoms. In this scenario, the child is improving or stable when high fevers and varying degrees of respiratory compromise occur. A chest X-ray will often show lobar consolidation. Immune dysregulation by influenza has been sug- gested as at least part of the reason for this (Heltzer et al., 2009). Diagnosis of influenza can be made with rapid antigen screening and nasal cultures.
Treatment is generally supportive as it is with other viral illnesses. Antiviral agents have been proven to be effective in shortening the course and sever- ity of the illness if started within 1–2 days of the symptoms. The seasonal influenza virus has been adept at developing resistance to the commonly used antiviral agents. The 2009 H1N1 virus has not developed such resis- tance as of this writing. However, it is different from the seasonal influenza in that it causes more morbidity and mortality among young children. It has been recommended that high-risk children be prophylactically treated with antiviral agents if they have been in close contact with a person who has a known case of influenza. Bacterial superinfections should be treated with appropriate antibiotic therapy, keeping in mind the frequency of Staphylococcus in this scenario.
Currently, the CDC recommends that all children under the age of 18 receive the influenza vaccine, as this is the most effective way to prevent outbreaks and to protect children from serious consequences of the flu.
Vaccination is especially essential for children who are at high risk, such as those with chronic pulmonary, cardiac, hematologic, immunologic, and metabolic conditions. In addition, household members of high-risk chil- dren should be immunized, as should all health-care workers and caregiv- ers. High-risk children, or family members of such children, should not receive the live nasal vaccines.
Adenovirus
Adenovirus is a common cause of fever and upper respiratory illnesses in children but can sometimes cause lower respiratory illness as well.
Adenoviral pneumonia causes the same type of symptoms as pneumonia from RSV or influenza; however, the symptoms may be more prolonged.
Children with adenovirus are more likely to have a persisting fever and conjunctivitis is not uncommon. Adenovirus is also more likely to cause chronic sequelae, including interstitial fibrosis and bronchiectasis.
Adenovirus is not susceptible to antiviral agents currently available, and therefore supportive therapy is all that is available for a patient with an ALRI caused by adenovirus.
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Human metapneumovirus
Human metapneumovirus (hMPV) is a viral pathogen that causes a wide spectrum of illnesses ranging from asymptomatic infection to severe bron- chiolitis. First named in 2001, hMPV tends to affect mainly patients between newborn and 6 years of age. The pathophysiology of the virus is similar to that of RSV and it is found to be the causative virus in 5–15% of infant bronchiolitis. The clinical presentation is similar to that of RSV as well, presenting with symptoms such as rhinorrhea, congestion, cough, tachy- pnea, and dyspnea (Maranich & Rajnik, 2009). Treatment of a child infected with hMPV is primarily supportive, focusing on adequate hydration and oxygenation. Severe disease can lead to respiratory failure, implying that careful clinical observation is imperative, especially in high-risk infants and children.