BRS – Pediatrics: Pulmonology

Source: BRS Pediatrics, 2019

I. Anatomy and Physiology of the Respiratory System

A. Development

1. By 16 weeks’ gestation, the bronchial tree has developed. By 26–28 weeks’ gestation, sufficient air sacs and pulmonary vasculature have developed so that the fetus is able to survive.
2. Alveolarization begins around 36 weeks’ gestational age with most alveoli forming during the first few years of life, followed by a slower rate later in childhood and continuing through adolescence.

B. Anatomy

1. The right lung contains three lobes, and the left lung contains two lobes, plus the lingula.
2. Infants are at higher risk for respiratory insufficiency than older children and adults because infants have anatomically smaller air passages, less compliant (stiffer) lungs with a more compliant chest wall, and less efficient pulmonary mechanics.
3. The cricoid cartilage ring is the narrowest part of pediatric airway, predisposing to upper airway obstruction with any inflammation or narrowing. A small incremental decrease in lumen diameter in infants and small children can be critical, resulting in a large increase in airway resistance and increased work of breathing.
4. Congenital malformations of the respiratory tract may be associated with other congenital anomalies, especially of the cardiovascular system.

C. Physiology

1. Pulmonary vascular resistance decreases after birth when the fetal pulmonary and systemic circulations separate and the lungs ventilate for the first time.
2. The primary function of the lungs is gas exchange.
3. Lung disorders may be classified as obstructive or restrictive.

a. Obstructive defects are secondary to decreased airflow through narrowed airways. Examples include asthma, bronchiolitis, and foreign body aspiration.
b. Restrictive defects are secondary to processes that decrease lung volume (the amount of air filling the alveoli). Examples include pulmonary edema, scoliosis, pulmonary fibrosis, and respiratory muscle weakness.

4. During normal respiration, the extrathoracic upper airway narrows during inspiration and the intrathoracic lower airways narrow during expiration.

II. Clinical Assessment of Pulmonary Disease
A. History is most important in determining the diagnosis of pulmonary disorders.
1. The antenatal, prenatal, and neonatal histories are very important because complications of pregnancy, fetal or postnatal tobacco exposure, prematurity, and airway instrumentation can predispose to pulmonary problems.
2. Past medical history should include previous respiratory problems, including frequent respiratory tract infections, cough, wheeze, stridor, snoring, and exercise intolerance.
3. Review of systems should include documentation of atopy (asthma), failure to thrive or steatorrhea (cystic fibrosis), choking (aspiration), and recurrent infections (immunodeficiencies).
4. Family history should include assessment for genetic diseases (e.g., cystic fibrosis, asthma).
5. Environmental history is extremely important because fumes, strong odors, tobacco smoke, allergens, animals, and day care attendance may cause or exacerbate pulmonary disease.
B. Physical examination should emphasize the chest and respiratory system.
1. In the general assessment, assess for evidence of increased work of breathing, such as tachypnea, nasal flaring, expiratory grunting, and chest wall retractions.
2. Evaluate the ears, nose, and throat for signs of obstruction, atopy, or infection.
3. Perform a chest examination.
a. Inspiratory stridor suggests extrathoracic obstruction, such as in croup and laryngomalacia (softening and weakness of laryngeal cartilage during the first year of life, in which the cartilage collapses into the airway, especially when in the supine position).
b. Expiratory wheezing suggests intrathoracic obstruction, such as in asthma and bronchiolitis.
c. Crackles or rales suggest parenchymal disease, such as in pneumonia and pulmonary edema.
d. Prolonged expiratory phase and/or a hyperinflated thorax suggest obstructive disease.
e. Rapid, shallow breathing and/or a small thorax suggest restrictive disease.
4. Assess for related findings in other organs, such as heart murmurs, a prominent second heart sound (suggests elevated pulmonary artery pressure), eczema, and digital clubbing.
C. Accessory tests help to evaluate pulmonary function.
1. Imaging studies may include chest radiograph (CXR), computed tomography (CT) scan, magnetic resonance imaging (MRI), and nuclear studies (e.g., ventilation–perfusion scans). Ultrasound is helpful to localize pleural effusions.
2. Arterial blood gas (ABG) is the gold standard to measure oxygenation (PO2) and ventilation (PCO2).
3. Pulse oximetry noninvasively measures oxygen saturation (SpO2).
4. Pulmonary function testing (PFT) helps determine the type and severity of pulmonary dysfunction. The most common PFTs measure airflow as a function of time (spirometry) and lung volumes (plethysmography).
D. Laryngoscopy and bronchoscopy are performed in some conditions to visualize the upper and lower airways and/or to obtain bronchoalveolar lavage specimens for laboratory analysis. Common indications include persistent or recurrent cough, stridor, wheezing, and pulmonary infiltrates.

III. Infectious Disorders of the Respiratory Tract
A. Epiglottitis (supraglottitis)
1. Definition. Epiglottitis is bacterial cellulitis of the supraglottic structures: epiglottis, arytenoids, and aryepiglottic folds.
2. Epidemiology. The disorder is most common in children 2–7 years of age, with equal incidence in males and females.
3. Etiology
a. Infection with Haemophilus influenzae type b (HIB) was the most common cause before HIB immunization. Epiglottitis is now rare because of the success of the HIB immunization program.
b. Group A β-hemolytic streptococcus, Streptococcus pneumoniae, and Staphylococcus
species may also cause epiglottitis.
4. Clinical features
a. Abrupt onset of rapidly progressive upper airway obstruction without a prodrome. The following signs and symptoms may occur:
1. High fever and toxic appearance
2. Muffled speech and quiet stridor
3. Dysphagia with drooling
4. Sitting forward in tripod position with neck hyperextension
b. Complete airway obstruction with respiratory arrest may occur suddenly.
c. Laboratory studies demonstrate leukocytosis with left shift. Ninety percent of patients have a positive blood culture, if the epiglottitis is secondary to HIB.
d. Epiglottis appears like a “thumbprint” on a lateral radiograph of the neck.
5. Differential diagnosis. Croup, bacterial tracheitis, and retropharyngeal abscess are diagnoses to also consider. Table 9-1 compares the clinical features that differentiate supraglottic disorders (e.g., epiglottitis) from subglottic disorders (e.g., viral croup).
6. Diagnosis. Epiglottitis should be suspected on the basis of clinical features. Visualization of a cherry red swollen epiglottis is made when the airway is established.
7. Management
a. Epiglottitis is a medical emergency.
b. Controlled nasotracheal intubation should be performed by experienced personnel in a controlled environment (e.g., operating room).
c. Before intubation, minimize stimulation while offering humidified oxygen. Avoid causing distress or examining the throat with a tongue depressor, as this may cause sudden respiratory arrest.
d. Intravenous antibiotic therapy typically includes a second- or third-generation intravenous cephalosporin to cover HIB and Streptococcus. If epiglottitis is secondary to HIB, rifampin prophylaxis is indicated for unimmunized household contacts younger than 4 years of age.
B. Laryngotracheobronchitis (croup)
1. Definition. Croup syndromes include viral croup and spasmodic croup and are secondary to mucosal inflammation and edema of the subglottic larynx, trachea, and bronchi.
2. Epidemiology
a. Viral croup is the most common cause of stridor. It typically occurs in children
6 months of age to 4 years of age in the late fall and winter. The male to female ratio is 2:1.
b. Spasmodic croup occurs year round in preschool age children.

3. Etiology
a. Viral croup is most commonly secondary to parainfluenza viruses. It may be recurrent owing to lack of complete immunity after initial infection, and because it can be caused by a variety of viruses in addition to parainfluenza.
b. The cause of spasmodic croup is unknown but possibly secondary to a
hypersensitivity reaction.
4. Clinical features
a. Viral croup
1. Begins with an upper respiratory infection prodrome for 2–3 days, followed by stridor and cough.
2. Symptoms include inspiratory stridor, fever, barky cough, and hoarse voice, which typically last 3–7 days. Respiratory distress may occur.
3. Stridor and cough worsen at night and with agitation.
4. Wheezing may occur if the lower respiratory tract is involved.
5. Anterior–posterior radiograph of the neck demonstrates the “steeple sign” of subglottic narrowing.
b. Spasmodic croup
1. Characteristic acute onset of stridor without fever or other symptoms usually occurs at night.
2. Spasmodic croup typically recurs and resolves without treatment.
5. Diagnosis. Croup should be suspected on the basis of clinical features.
6. Management
a. Supportive care may involve hydration, antipyretics, and possibly oxygen, in addition to avoiding agitation. Improvement has been anecdotally noted when patients are exposed to humidified air, although use of cool mist or steam has not been proven efficacious.
b. A single dose of systemic corticosteroids, such as oral or intramuscular dexamethasone, has been shown to reduce croup severity and duration.
c. Children with respiratory distress get transient improvement from racemic epinephrine aerosols, which vasoconstrict subglottic tissues.
d. Hospitalization is indicated for children in respiratory distress.
C. Bacterial tracheitis is an uncommon, but re-emerging, cause of stridor.
1. Definition. Bacterial tracheitis is acute infectious inflammation of the trachea.
2. Etiology. Causes include Staphylococcus aureus (60%), Streptococcus, Haemophilus influenzae, and Moraxella catarrhalis.
3. Clinical features
a. Abrupt deterioration
b. Toxicity, high fever, stridor, brassy cough, choking, and acute respiratory distress secondary to mucus and pus in the trachea
4. Management. Bronchoscopy can be both diagnostic and therapeutic to remove secretions and sloughed tissue from the trachea. Appropriate antistaphylococcal antibiotics and airway support are indicated.
D. Pertussis. This highly contagious respiratory infection is also known as “whooping cough.”
1. Etiology. Bordetella pertussis is the major pathogen responsible for infection. Bordetella parapertussis causes illness that appears clinically very similar to pertussis.
2. Epidemiology and pathophysiology
a. Adolescents and adults whose immunity has waned are the major source for pertussis infection of unimmunized or underimmunized children.
b. Sneezed or coughed droplets are inhaled into airways of close contacts. A toxin is subsequently produced, which damages respiratory cells and enters the

bloodstream.
c. Infants younger than 6 months of age are most at risk for severe disease.
d. Routine immunization beginning at 2 months of age has been effective in reducing the overall incidence of pertussis infection (see Chapter 1, section III.C.2).
3. Clinical features
a. The incubation period is typically 7–10 days.
b. Pertussis is characterized by three stages.
1. Catarrhal stage (1–2 weeks) is characterized by upper respiratory symptoms such as rhinorrhea, nasal congestion, conjunctival redness, and low-grade fever.
2. Paroxysmal stage (1–6 weeks) is characterized by paroxysms of coughing that are the hallmark of pertussis. A whoop is an inspiratory gasp that may be heard at the very end of a coughing fit (although rarely observed in young infants). The coughing fits are exhausting, and posttussive vomiting is common. Young infants may have cyanosis, apnea, and choking during the paroxysms of cough. Between the coughing fits, children appear well and are afebrile.
3. Convalescent phase (weeks to months) is a recovery stage in which paroxysmal cough continues but becomes less frequent and severe over time.
4. Diagnosis
a. Diagnosis is suspected based on clinical features.
b. White blood cell (WBC) count is elevated with a significant lymphocytosis.
c. Diagnosis is confirmed by identification of B. pertussis by nasopharyngeal culture or polymerase chain reaction (PCR).
5. Management
a. Hospitalization of young infants often occurs during the paroxysmal phase because of choking, apnea, or cyanosis. Supportive care and oxygen (if needed) are important therapies.
b. Macrolide antibiotics are given to all patients and close contacts to prevent the spread of infection. Antibiotics do not alter the patient’s clinical course, unless they are administered during the catarrhal phase or very early in the paroxysmal phase.
c. Respiratory isolation is needed until antibiotics have been given for at least 5 days.
E. Bronchiolitis
1. Definition. Bronchiolitis is inflammatory bronchiolar obstruction with cellular debris and mucus plugging, most commonly secondary to a viral lower respiratory tract infection.
2. Epidemiology
a. Bronchiolitis is the most common lower respiratory tract infection in the first
2 years of life and the most common cause of hospitalization during the first year.
b. This disorder predominantly affects children younger than 2 years of age.
c. The male to female ratio is 2:1.
d. Epidemics occur from November to April.
e. Risk of infection is increased with day care attendance, multiple siblings, exposure to tobacco smoke, and lack of breastfeeding.
f. More significant disease occurs in patients with chronic lung disease, congenital heart disease, history of prematurity, immunodeficiency diseases, and genetic abnormalities, as well as in infants younger than 3 months of age.
3. Etiology
a. Respiratory syncytial virus (RSV) is the most common cause.
b. Less common causes include human metapneumovirus, parainfluenza, adenovirus,

rhinovirus, influenza, and coronavirus.
4. Clinical features
a. Onset is gradual, with upper respiratory symptoms, such as rhinorrhea, nasal congestion, fever, and cough.
b. Progression of respiratory symptoms includes tachypnea, fine rales, wheezing, and increased work of breathing.
c. Hypoxemia may occur.
d. Apnea may occur, especially in young infants and in children with a history of apnea of prematurity.
e. CXR may reveal hyperinflation with air trapping, patchy infiltrates, and
atelectasis.
f. Improvement is usually noted within 2 weeks. More than 50% develop recurrent wheezing.
g. Complications may include apnea, respiratory insufficiency, respiratory failure, and death. Bacterial superinfection occurs rarely.
h. Immunity is incomplete, although repeat infections tend to be less severe.
5. Diagnosis is made on the basis of clinical features. Virologic testing is available if needed.
6. Management
a. Treatment is primarily supportive with nasal bulb suctioning (infants are obligatory nose breathers), hydration, and oxygen as needed for SpO2 < 90%.
b. Hand decontamination (preferably with alcohol-based rubs) is an essential part of contact isolation to prevent spread of infection.
c. Exposure to environmental tobacco smoke should be avoided.
d. Nebulized hypertonic saline may help hospitalized infants, but albuterol, epinephrine, and corticosteroids are no longer recommended.
e. Hospitalization is indicated for respiratory distress, hypoxemia, apnea, dehydration, or underlying cardiopulmonary disease.
f. RSV monoclonal antibody (palivizumab) may be given prophylactically as five monthly intramuscular injections during RSV season to prevent severe disease in infants with a history of prematurity, chronic lung disease, or hemodynamically significant congenital heart disease.
F. Pneumonia
1. Definition. Pneumonia involves infection and inflammation of the lung parenchyma associated with infiltrates on CXR.
2. Epidemiology. Pneumonia is associated with poverty, multiple siblings, exposure to tobacco smoke, and prematurity, as well as urban residence.
3. Etiology. Causes may be classified based on the child’s age (Table 9-2).
a. Viruses are the most common cause of pneumonia in all age groups.
b. S. pneumoniae is the single most common bacterial pathogen after first few weeks of life.
c. Staphylococcal pneumonias are often complicated by empyema.
d. Recurrent or persistent pulmonary infiltrates may have many causes and are further differentiated if occurring in a single lobe versus multiple lobes (Table 9-3).
4. Clinical features, diagnosis, and management vary depending on the etiologic agent.
a. Viral pneumonia
1. Symptoms often begin with upper respiratory complaints, such as nasal congestion and rhinorrhea. Fever, cough, and dyspnea typically follow.
2. Physical examination may demonstrate tachypnea, wheezing, rales, or respiratory distress.

3. Diagnosis is suggested by interstitial infiltrates on CXR and a WBC count
<20,000 cells/mm3 with a lymphocyte predominance.
4. Management is supportive.
b. Bacterial pneumonia
1. Symptoms have more rapid onset and greater severity. Fever, cough, and dyspnea typically occur without preceding upper respiratory symptoms.
2. Physical examination may demonstrate rales, tachypnea, decreased breath sounds, egophony (changes in voice transmission through consolidated lung), and evidence of respiratory distress.
3. Diagnosis is suggested by a WBC count >20,000 cells/mm3 with a neutrophil predominance, elevated C-reactive protein (CRP), and lobar consolidation on CXR.
4. Management includes appropriate antibiotics and supportive care.
c. Chlamydia trachomatis is a cause of afebrile pneumonia at 1–3 months of age, secondary to a perinatal-acquired infection from the maternal genital tract.
1. Symptoms include a staccato-type cough, dyspnea, and absence of fever. A history of conjunctivitis after birth may be identified in 50% of patients.
2. Physical examination may demonstrate tachypnea and wheezing.
3. Diagnosis is suggested by eosinophilia and a CXR with interstitial infiltrates. Definitive diagnosis is by positive culture, antigen detection, or nucleic acid amplification test from conjunctiva or nasopharynx.
4. Management includes an oral macrolide.
d. Mycoplasma pneumoniae is one of the most common causes of pneumonia in older children and adolescents.
1. Symptoms include low-grade fever, chills, nonproductive cough, headache, pharyngitis, and malaise. The cough may last 3–4 weeks.
2. Lung examination may demonstrate widespread rales. Examination findings are often worse than expected by history.
3. Diagnosis
a. Positive cold agglutinins are suggestive but are not specific.
b. Elevated EIA-IgM (enzyme-linked immunoassay for the detection of IgM) is useful; PCR obtained by a nasopharyngeal swab is more sensitive.
c. CXR findings are variable and may show unilateral or bilateral infiltrates.
4. Management includes an oral macrolide, tetracycline, or quinolone.
e. Mycobacterium tuberculosis should be considered in all patients with risk factors for tuberculosis (see Chapter 7, section XVII.C).

Table 9-1
Differentiating Features of Supraglottic and Subglottic Disorders*

Feature Supraglottic Disorders Subglottic Disorders
Stridor Quiet Loud
Cough None Barky
Voice Muffled Hoarse
Dysphagia/drooling Present Absent
Fever High Low to moderate (croup)
High (tracheitis)
Toxicity Present Absent, unless tracheitis is present
Posture Neck extended, tripod position Normal
*Supraglottic disorders include epiglottitis and retropharyngeal abscess. Subglottic disorders include bacterial tracheitis and viral croup.

Table 9-2
Age and Its Relationship to Pneumonia Etiology

Age Typical Causes
0–3 months Congenital infections, such as syphilis, toxoplasmosis, CMV, rubella, herpes simplex virus, and tuberculosis
Intrapartum-acquired infections, such as group B streptococcus (most common infection), Gram negative rods,
and Listeria monocytogenes
Postpartum infections, such as RSV and other respiratory viruses
Afebrile pneumonitis caused by Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, CMV, and
PCP
3 months–
5 years Viruses, such as adenovirus, influenza A and B, parainfluenza, HMPV, and RSV (note that RSV pneumonia is
generally uncommon beyond 2–3 years of age)
Bacteria, most commonly Streptococcus pneumoniae, but may also include Staphylococcus aureus and HIB
Age 6 and older Mycoplasma pneumoniae and Chlamydia pneumoniae increasingly common
Viruses, such as adenovirus, influenza A and B, HMPV, and parainfluenza
Bacteria, most commonly S. pneumoniae
CMV = cytomegalovirus; RSV = respiratory syncytial virus; HMPV = human metapneumovirus; HIB = Haemophilus influenzae type b; PCP = Pneumocystis jiroveci pneumonia.

Table 9-3
Causes of Recurrent or Persistent Pulmonary Infiltrates

Single Lobe Multiple Lobes
Intraluminal obstruction Aspiration
Foreign body Impaired gag or swallow
Tumor Esophageal obstruction or dysmotility, GERD
Mucus plug Mucociliary clearance dysfunction
Extraluminal obstruction Cystic fibrosis
Enlarged lymph node from infection or malignancy Ciliary dyskinesia (e.g., immotile cilia syndrome)
Bronchopulmonary dysplasia (chronic lung disease)
Structural abnormalities Congenital heart disease
Bronchial stenosis α1-antitrypsin deficiency
Bronchiectasis Sickle cell disease
Right middle lobe syndrome Hypersensitivity pneumonitis
Congenital lung abnormalities, such as cysts or sequestration Pulmonary hemosiderosis
Asthma
Immunodeficiency diseases
GERD = gastroesophageal reflux disease.

IV. Noninfectious Disorders of the Respiratory Tract
A. Asthma (reactive airway disease)
1. Definition
a. Asthma is a chronic inflammatory disorder of the airways that causes recurrent episodes of wheezing, cough, dyspnea, and chest tightness.
b. Symptoms are typically associated with widespread, variable airflow obstruction that is at least partially reversible, either spontaneously or with therapy.
c. Inflammation causes airway hyperresponsiveness to many stimuli.
2. Epidemiology. Asthma is the most common chronic pediatric disease.
a. Between 50 and 80% of children who have asthma develop symptoms before their fifth birthday.
b. Most patients with recurrent episodes of viral-triggered wheezing during their first year of life do not become asthmatics. This risk is increased if the child has a positive asthma predictive index. A positive asthma predictive index is either
1. One of the following: physician diagnosis of atopic dermatitis, parental history of asthma, or evidence of sensitization to aeroallergens OR
2. Two of the following: wheezing apart from colds, sensitization to foods, ≥4% eosinophils on CBC differential
c. Higher prevalence and severity in African American, Puerto Rican, and low socioeconomic populations.
3. Etiology
a. Predisposing factors involve interplay between host and environment, including multiple interacting genes, atopy, family history of asthma, and exposure to tobacco smoke. Viral respiratory infections, diet, and pollution can increase susceptibility in predisposed patients.
b. Triggers of exacerbations include respiratory infections, exercise, cold air, emotions, allergens, gastroesophageal reflux, and exposure to pollutants.
c. Asthma may accompany other acute or chronic lung diseases, such as cystic fibrosis.
4. Pathophysiology. Increased production and infiltration of inflammatory cells and mediators result in smooth muscle bronchoconstriction, airway mucosal edema, increased secretions with airway plugging, and possible airway wall remodeling.
5. Clinical features
a. Typical features during an exacerbation include tachypnea, dyspnea, nasal flaring, retractions, and multiphonic wheezing with a prolonged expiratory phase.
b. Some patients have only chronic or recurrent cough (especially at night).
c. CXR often reveals hyperinflation, peribronchial thickening, and patchy atelectasis.
d. PFTs reveal increased lung volumes and decreased expiratory flow rates.
6. Diagnosis
a. The basis of diagnosis is clinical features and usually a therapeutic response to a bronchodilator trial.
b. Spirometry (possibly with bronchoprovocation) can support diagnosis and should be attempted in a child 5 years of age or older. It can show airflow obstruction, which reverses following administration of bronchodilators.
c. “All that wheezes is not asthma.”
1. Differential diagnosis of acute wheezing (Figure 9-1)
2. Differential diagnosis of recurrent or chronic wheezing (Figure 9-2)

7. Management. Therapy is initiated based on asthma severity, and is subsequently adjusted to obtain the goal of asthma control, with reduction of ongoing impairment as well as prevention of future risk.
a. Assessment and monitoring are performed at each visit to assess asthma control, medication administration technique, and patient adherence, as well as to address concerns.
b. Education is provided for self-monitoring and to reinforce self-management with oral demonstrations and written instructions. A spacer device (valved holding chamber) is recommended for administration of metered-dose inhalers.
c. Measures are recommended to control environmental factors (e.g., avoidance of allergens, pollutants, irritants) and treat comorbid conditions (e.g., allergic rhinitis, gastroesophageal reflux, obesity, stress).
d. Medications are prescribed and titrated using a stepwise approach. National guidelines classify asthma treatment by severity for three different age groups: 0– 4 years, 5–11 years, and 12 years and older. Table 9-4 reviews the classification of
asthma and initiating therapy. Table 9-5 reviews the stepwise approach to managing asthma long term.
1. Asthma is usually classified as “intermittent” if symptoms and/or short-acting beta- agonist (SABA) use are ≤2 days/week, nighttime awakenings are
≤2×/month, and corticosteroid-requiring exacerbations are 0–1×/year. Treatment is with an short-acting beta-2 agonist (SABA), usually albuterol, as needed for quick relief of symptoms.
2. Patients with more frequent symptoms are classified as mild, moderate, or severe “persistent” asthma and require long-term controller medications, in addition to SABA for quick relief of symptoms.
a. Inhaled corticosteroids (ICS) are the most effective long-term control therapy for all ages. Start with low dose for mild persistent asthma.
b. Leukotriene modifiers (leukotriene receptor antagonist [LTRA]), such as montelukast, are alternative although less effective controllers.
c. With increased symptoms/severity (moderate–severe persistent asthma), consider increasing the ICS dose and/or adding an inhaled long-acting beta-agonist (LABA), theophylline, or LTRA.
3. Long-term control therapy with low-dose ICS or montelukast should also be considered for children who are 0–4 years of age and who have had ≥4 episodes of wheezing in the past year that lasted >1 day and affected sleep AND who have a positive Asthma Predictive Index.
4. To prevent exercise-induced bronchospasm, pretreatment with SABA or LTRA is recommended, in addition to a warm-up period.
5. Acute exacerbations are treated with repetitive or continuous inhaled SABA, a short course of systemic corticosteroids, and supplemental oxygen as needed.
B. Cystic fibrosis (CF)
1. Definition. CF is a chronic progressive multisystem genetic disorder with major manifestations in the respiratory, gastrointestinal (GI), and reproductive systems.
2. Epidemiology
a. CF affects 1 in 3000 Caucasians and is less common in Hispanics, African Americans, and Asians.
b. Five percent of Caucasians are carriers.
c. Median age of survival has increased to 41 years with CF center–based care.
3. Etiology. CF is an autosomal recessive disease resulting from genetic mutations on
chromosome 7. 2000 known mutations cause a wide spectrum of phenotypes ranging

from mild and atypical to severe and classic.
4. Pathophysiology
a. The genetic defect produces an abnormal cystic fibrosis transmembrane conductance regulator (CFTR) protein that causes sodium and chloride transport dysfunction in exocrine epithelial cells and submucosal glands.
b. In the lungs, abnormal thick, viscous mucus results in airway obstruction, inflammation, and infection causing bronchiectasis.
5. Clinical features
a. Recurrent or chronic respiratory symptoms, steatorrhea, and failure to thrive (FTT) are typical presenting features. Clinical expression is variable. See Figure 9-3 for the multisystem signs and symptoms of CF.
b. Chronic, recurrent sinopulmonary disease includes chronic productive cough, dyspnea, lung hyperinflation, lung crackles, wheezing, pansinusitis, nasal polyps, digital clubbing, and progressive hypoxemia.
1. PFTs show decreased respiratory flow rates (consistent with obstruction) and eventually decreased lung volumes (consistent with restriction).
2. Pneumonia develops as the lungs become colonized, first with Staphylococcus aureus and later with mucoid Pseudomonas aeruginosa.
3. Common pulmonary complications include hemoptysis, pneumothorax, recurrent pneumonia exacerbations, severe bronchiectasis, allergic bronchopulmonary aspergillosis, pulmonary fibrosis, cor pulmonale, and eventually respiratory failure.
c. GI and nutritional abnormalities, include pancreatic insufficiency in 90% of patients, with malabsorption predisposing to malnutrition, deficiencies of vitamins A, D, E, and K, and FTT, with possible later complication of CF-related diabetes mellitus.
d. Salt depletion syndromes secondary to sweat electrolyte losses
e. Male urogenital abnormalities, including congenital absence of the vas deferens
6. Diagnosis requires the following:
a. One or more characteristic phenotypic features or positive family history or
increased immunoreactive trypsinogen (IRT) on newborn screen AND
b. Laboratory evidence of abnormal CFTR function, including sweat chloride
>60 mmol/L or two CFTR mutations or a characteristic ion transport abnormality across the nasal epithelium
7. Management. Goals are to preserve the lung function, optimize nutrition, and both prevent and treat complications, while maintaining quality of life.
a. Airway clearance therapies (e.g., postural drainage and percussion, chest wall oscillating vest) combined with mucus-altering therapies (e.g., DNase, hypertonic saline) to remove abnormal secretions
b. Antibiotics (inhaled, oral, IV) to control chronic airway infection and treat acute pulmonary exacerbations
c. High-calorie diet, pancreatic enzyme replacement, fat-soluble vitamins (A, D, E, and K), and insulin, if needed, to optimize nutritional status
d. Anti-inflammatory therapy (e.g., high-dose ibuprofen, but not corticosteroids) to treat chronic airway inflammation
e. Mutation-specific disease-modifying therapies (e.g., ivacaftor) to correct gene defects
f. Oxygen as needed for hypoxemia
g. Lung transplantation
h. Psychosocial support for patients and families

C. Bronchopulmonary dysplasia (BPD; also termed chronic lung disease of infancy [CLDI]; see also Chapter 4, section VI.G.2.a)
1. Definition. Infants with lung disease of prematurity who require supplemental oxygen
≥28 postnatal days are classified as having mild, moderate, or severe BPD, depending on the level of respiratory support needed.
2. Epidemiology. BPD follows exposure of premature lungs to various antenatal and postnatal insults. Risk increases with increased prematurity and decreased birth weight.
3. Etiology and pathophysiology
a. Previously, the development of BPD followed treatment with high FiO2 (fraction of inspired oxygen) and aggressive mechanical ventilation, which resulted in diffuse airway damage, smooth muscle hypertrophy, polymorphonuclear cell (PMN) inflammation, and parenchymal fibrosis.
b. The current BPD phenotype is manifest primarily by impaired alveolar and vascular development secondary to extreme prematurity. “New” BPD has milder airway injury, inflammation, and fibrosis than “old” BPD because of improved neonatology practices.
c. Decreased and simplified alveoli result in less surface area for gas exchange.
4. Clinical features vary and range from transient oxygen dependency to a prolonged need for ventilatory support.
a. Diminished oxygenation (decreased PaO2) and hypercarbia (increased PaCO2) are often found on ABG testing.
b. Chronic increased work of breathing with intermittent episodes of tachypnea, wheezing, sputum production, and respiratory distress.
c. Frequent respiratory tract infections, airway hyperreactivity, and pulmonary hypertension may result.
d. CXR is diffusely hazy to coarsely irregular and may remain abnormal for several years.
e. Nonpulmonary manifestations include increased caloric needs, feeding intolerance, delayed growth, and neurodevelopmental sequelae.
5. Management
a. Goals of treatment are to minimize the lung damage, promote growth of new lung tissue, maintain optimal oxygenation, and prevent complications.
b. Most important therapy is supplemental oxygen, which may be needed after discharge to home.
c. Optimize high caloric intake for growth.
d. Consider bronchodilators, diuretics, and/or fluid restriction to transiently improve pulmonary function.
e. Prevent complicating infections through avoidance of ill contacts, appropriate immunization practices, and RSV prophylaxis.
f. Avoid passive smoke exposure.
g. Focus on early identification and treatment of complications, such as subglottic stenosis, gastroesophageal reflux disease, and tracheobronchomalacia.
6. Prognosis. Pulmonary symptoms and disease usually improve with time and lung growth. Some patients have increased risk of rehospitalization, continued airway hyperreactivity, exercise limitation, delays in development, and poor tolerance of respiratory infections. There is a possibility of risk of developing chronic obstructive pulmonary disease (COPD) during adulthood.
D. Foreign body aspiration
1. Epidemiology. Children 3 months–5 years of age are at greatest risk for small object aspiration.

2. Etiology. Typical aspirated objects include seeds, popcorn, hot dogs, candy, grapes, and small toy parts.
3. Clinical features depend on location and biologic reactivity of the material aspirated.
a. History may elicit choking episode in 50–80% of cases.
b. Laryngotracheal foreign bodies (extrathoracic) result in cough, hoarseness, and
inspiratory stridor.
c. Bronchial foreign bodies (intrathoracic; right bronchus slightly more common than left)
1. Asymmetric findings on auscultation
2. Complete obstruction with atelectasis, partial ball-valve obstruction with unilateral emphysema, or no obstruction that initially can be asymptomatic.
3. Localized wheezing, persistent pneumonia, chronic cough, or hemoptysis
d. Esophageal foreign bodies may compress the trachea, producing respiratory symptoms.
4. Diagnosis is challenging. Have a high index of suspicion!
a. A radiopaque object is evident on CXR in only 15% of cases.
b. Consider inspiratory and expiratory films, or bilateral decubitus films in young children who cannot inspire and expire on command, or fluoroscopy to identify air trapping distal to a foreign body.
5. Management
a. Basic life support is the initial management for a severe choking episode.
b. Natural cough, if present, is the most effective expulsive mechanism.
c. Foreign bodies that remain in the airway must be removed by bronchoscopy.
E. Apnea, apparent life-threatening event (ALTE), Brief resolved unexplained event (BRUE), sudden infant death syndrome (SIDS), and obstructive sleep apnea syndrome (OSAS)
1. Definitions
a. Apnea of infancy is the unexplained cessation of breathing for ≥ 20 seconds, or a shorter respiratory pause associated with bradycardia, cyanosis, pallor, or hypotonia in a full-term infant.
1. Respiratory pause may be central (no respiratory effort), obstructive (efforts at respiration are made but are unsuccessful, usually because of upper airway obstruction), or both.
2. Short central apnea for ≤15 seconds is normal at all ages.
b. Apnea of prematurity is the unexplained cessation of breathing for ≥ 20 seconds in a premature infant (see also Chapter 4, section IX). This usually resolves by 37–
40 weeks postconceptual age.
c. Periodic breathing is a normal breathing pattern in young infants with three or more respiratory pauses lasting at least 3 seconds each, with less than 20 seconds of normal respiration in between.
d. ALTE/BRUE is a frightening event characterized by some combination of apnea, color change, change in muscle tone, choking, or gagging, in which recovery occurs only after stimulation or resuscitation.
e. SIDS is the sudden death of a child younger than 1 year of age that is unexplained after a thorough investigation, including a complete autopsy, an examination of the death scene, and a review of the clinical history.
f. OSAS is a disorder of breathing during sleep that is characterized by prolonged partial upper airway obstruction and/or intermittent complete obstruction (obstructive apnea) that disrupts normal ventilation during sleep and normal sleep patterns. Obstructive sleep apnea (OSA) is typically worse during rapid eye movement (REM) sleep. Ongoing OSA is associated with risk for neurocognitive

and cardiovascular morbidity.
2. Epidemiology
a. SIDS reaches its peak incidence at 2–4 months of age, and 95% of cases occur before 6 months of age.
b. Risk factors for SIDS
1. Prone sleeping position
2. Soft bedding, overbundling, and overheating
3. Prematurity
4. Being the twin of a sibling who died of SIDS
5. Low birth weight or growth retardation
6. Recent illness
7. Lack of breastfeeding
8. Maternal smoking, drug abuse, or infection
3. Etiology
a. Apnea of prematurity is usually caused by immature central respiratory center control.
b. Obstructive apnea may be secondary to craniofacial anomalies, adenotonsillar hypertrophy, obesity, or hypotonia.
c. The cause of SIDS is unknown.
d. No definite cause and effect relationship has been proven among apnea, ALTE/BRUE, and SIDS.
4. Differential diagnosis of ALTE/BRUE
a. Seizure disorder
b. Gastroesophageal reflux disease (GERD)
c. Upper airway obstruction
d. Intracranial mass lesion
e. Sepsis or other infections, including RSV, pertussis, and meningitis
f. Metabolic abnormalities, including electrolyte imbalance and hypoglycemia
g. Inborn errors of metabolism
h. Arrhythmia, including long QT syndrome
i. Abnormal central control of breathing
j. Munchausen by proxy
k. Nonaccidental trauma (shaken baby syndrome)
5. Evaluation
a. Detailed history and physical examination, especially HEENT (head, eyes, ears, nose, and throat), is essential.
b. Further testing is based on clinical impression from the history and physical examination and may include the following:
1. Hospital observation and monitoring
2. Blood work, including complete blood count, ABG, electrolytes, and evaluation for infection
3. CXR, electrocardiogram, and electroencephalogram
4. Multichannel recording (sleep study), which simultaneously evaluates oxygen saturation, airflow, chest wall movement, and cardiac rhythm
5. Barium esophagram or pH probe study to evaluate for GERD
6. Imaging studies of the head and neck
7. Workup for metabolic disease
6. Management
a. For infant apnea and ALTE, teach caregivers cardiopulmonary resuscitation techniques.

b. For moderate–severe OSAS, consider adenotonsillectomy and/or continuous positive airway pressure (CPAP) therapy.
c. Home cardiorespiratory monitors should not be prescribed to prevent SIDS, and the following prevention strategies should be followed:
1. Sleep on the back
2. Firm bedding without pillows or blankets
3. Avoid overheating
4. Smoke-free environment
5. Early prenatal care and regular well-child care
6. Breastfeed

FIGURE 9.1 Differential diagnosis of acute wheezing.

FIGURE 9.2 Differential diagnosis of recurrent or chronic wheezing. BPD/CLD = bronchopulmonary dysplasia/chronic lung disease.

Table 9-4
Classifying Asthma Severity and Initiating Therapy in Patients Not Taking Long-Term Controller Medications

Components of Severity Classifying Asthma
Severity
Intermittent Persistent
Mild Moderate Severe
Ages 0–4 Ages 5–11 Ages
0–4 Ages
5–11 Ages
0–4 Ages 5–11 Ages
0–4 Ages 5–
11
Symptoms ≤2 days per week >2 days per week but not
daily Daily Throughout the day
Night awakenings 0 <2× per month 1–2×
per month 3–4×
per month 3–4×
per month >1× per week but not
nightly >1×
per week Often 7× per
week
Short-acting beta-agonist: use for symptom control ≤2 days per week >2 days per week but not
daily Daily Several times per day
Interference with activity None Minor
limitation Some limitation Extremely
limited
Lung function: FEV1 or peak flow N/A Normal between exacerbations
(>80%) N/A >80% N/A 60–80% N/A <60%
Exacerbations In general, more frequent and severe exacerbations (e.g., hospitalizations, urgent care, intensive
care unit admission) indicate greater underlying disease severity
Recommended step for initiating therapy (see
Table 9-5)
Step 1 Step 2 Step 3 Step 3 or 4
National Asthma Education and Prevention Program, Third Expert Panel on the Diagnosis and Management of Asthma. Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. Bethesda (MD): National Heart, Lung, and Blood Institute (US), August 2007:40 and 42.
FEV1 = forced expiratory volume during the first second of forced breath.
Table 9-5
Stepwise Approach to Managing Asthma Long Term

STEP-UP MEDICATION IF NEEDED (Check Medication Adherence, Inhaler Technique, Other Contributing Factors)
STEP-DOWN MEDICATION (If Asthma Is Well Controlled for at Least 3 Months)
Step 1 Step
2 Step 3 Step 4 Step 5 Step 6
Intermittent Asthma Persistent Asthma (daily medication)
0–4 years SABA
as needed Low- dose ICS Medium-dose ICS Medium-dose
ICS + either LABA or montelukast High-dose ICS + either LABA or
montelukast High-dose ICS + either LABA or
montelukast + oral
corticosteroids
5–
11 years SABA
as needed Low- dose
ICS Low-dose ICS + either LABA, LTRA or theophylline OR
Medium-dose ICS Medium-dose ICS + LABA High-dose ICS + LABA High-dose
ICS + LABA + oral corticosteroids
>12 years SABA
as needed Low- dose
ICS Low-dose ICS + LABA OR
Medium-dose ICS Medium-dose ICS + LABA High-dose ICS + LABA High-dose
ICS + LABA + oral corticosteroids
Adapted from National Asthma Education and Prevention Program, Third Expert Panel on the Diagnosis and Management of Asthma. Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. Bethesda (MD): National Heart, Lung, and Blood Institute (US), August 2007:42.
Quick Relief Medication: SABA as needed for relief of symptoms. Short course of oral steroids may be needed for exacerbations.
SABA = short-acting beta-2 agonist; ICS = inhaled corticosteroid; LABA = long-acting inhaled beta-2 agonist; LTRA = leukotriene receptor antagonist.

FIGURE 9.3 Features of cystic fibrosis.

Review Test
1. A 2-year-old toddler presents with a 3-day history of increasing inspiratory stridor, cough, and increased work of breathing. On examination, you confirm the inspiratory stridor and also note intercostal retractions and tachypnea with a respiratory rate of 44 breaths/minute. Which of the following is correct regarding the cause and management of the probable diagnosis?
A. Parainfluenza virus is the most likely cause.
B. Foreign body aspiration is unlikely because of the absence of a history of choking.
C. Corticosteroid therapy is contraindicated.
D. A “thumbprint sign” will be found on a lateral radiograph of the neck.
E. Antibiotics against Staphylococcus aureus are indicated.
2. A 5-month-old female infant in a day care facility develops a low-grade fever (temperature up to 100.8°F [38.2°C]), rhinorrhea, and cough. A few days later, she is brought to the emergency department with tachypnea, chest retractions, diffuse expiratory wheezing, and fine inspiratory crackles bilaterally. Which of the following is correct regarding her likely diagnosis?
A. Chest radiography will demonstrate decreased lung volumes with bilateral lobar consolidation.
B. Chlamydia trachomatis should be considered as a possible etiologic agent.
C. Supportive care is the most important management.
D. Intravenous antibiotics should be started.
E. Bronchoscopy is indicated.
3. A previously healthy 13-year-old boy presents with a 2-week history of nonproductive cough and low-grade fever. On examination, you note a normal respiratory rate and no evidence of respiratory distress but are surprised to hear inspiratory rales at the bilateral lung bases. Which of the following is the most likely cause of pneumonia in this adolescent?
A. Pneumocystis jiroveci
B. Staphylococcus aureus
C. Group B streptococcus
D. Bordetella pertussis
E. Mycoplasma pneumoniae
4. A 7-month-old male infant presents with failure to thrive, and he has had two previous episodes of pneumonia. Past medical history is also significant for meconium ileus during the neonatal period. Which of the following is correct regarding his likely diagnosis?
A. Electrolytes demonstrate hypernatremic, hyperchloremic metabolic acidosis.
B. His lungs are likely colonized with Staphylococcus aureus.
C. Pulmonary function studies show decreased lung volume consistent with restrictive lung disease.
D. There is a 50% chance that a subsequent sibling will have the same illness.
E. Pathophysiology involves abnormal calcium transport.
5. A 5-year-old girl presents with failure to thrive. Workup reveals a sweat chloride level of 90 mmol/L, which is consistent with cystic fibrosis. Which of the following is true regarding this patient’s management?
A. Dietary restriction is the preferred treatment for malabsorption from pancreatic insufficiency.
B. Antibiotic therapy should be avoided to prevent development of resistant organisms.
C. Mucus-altering therapies are ineffective in this condition.
D. Replacement of vitamins A, D, E, and K is necessary.
E. Chest physical therapy provides little added benefit.

6. A male infant born at 26 weeks’ gestation was diagnosed with surfactant deficiency syndrome. He required 3 months of mechanical ventilatory support and oxygen therapy. Now he is ready for discharge from the neonatal intensive care unit and will go home on 0.25 L/minute of oxygen by nasal cannula. Which of the following is correct?
A. He would be a candidate for palivizumab prophylaxis during respiratory syncytial virus season.
B. Because of the difficulties breathing and swallowing in young premature infants, his caloric intake should be minimized.
C. His lung function will continue to deteriorate with time and further growth.
D. His chest radiograph will be normal because he has improved clinically.
E. His lung disease should not affect his development.
7. A 3-month-old female infant required stimulation by her mother when she became blue and limp after feeding. In the emergency department, the physical examination is completely normal. Which of the following is correct regarding her presentation, evaluation, and management?
A. A home apnea monitor should be ordered to prevent sudden infant death syndrome (SIDS).
B. Consideration should be given for further workup, including possible electroencephalogram to rule out seizure disorder and pH probe study to rule out gastroesophageal reflux.
C. It is not useful to observe the infant feeding in the emergency department.
D. It is likely that this infant may later have SIDS.
E. These parents should now co-sleep with their infant to monitor for any future events.
8. A 3-year-old boy presents with acute onset of fever (temperature up to 103.5°F [39.7°C]), diminished appetite, and drooling. He has been previously well, and inspection of his immunization records reveals that all are up-to-date for his age. On examination, you note that he appears very ill and prefers to sit leaning forward on his hands with his neck hyperextended. His voice is muffled. Which of the following is correct regarding his likely diagnosis?
A. This patient likely has bacterial tracheitis and should be started on antistaphylococcal antibiotics.
B. Racemic epinephrine should be administered immediately.
C. Anesthesiology and otolaryngology should be consulted to visualize his airway and intubate him in a controlled environment (e.g., operating room).
D. An anterior–posterior radiograph of the neck will show a “steeple sign.”
E. The throat should be examined with a tongue depressor to rule out a retropharyngeal abscess.
9. A 6-week-old female infant presents with increased work of breathing and a staccato-type cough for 3 days. On physical examination you note a temperature of 98.8°F (37.1°C), a respiratory rate of 60 breaths/minute, and bilateral conjunctival erythema. The lungs are clear except for mild wheezing at the bilateral lung bases. Which of the following is correct regarding her likely diagnosis?
A. Pneumonia is unlikely given the absence of fever, and therefore a noninfectious cause of the patient’s symptoms should be sought.
B. Infection was transmitted by a maternal genital infection.
C. Blood culture will be positive in 50% of cases.
D. Corticosteroids are indicated and will improve the patient’s clinical course.
E. Inhaled mucolytics should be considered.
10. A 9-year-old girl with asthma is brought to the office for the first time. On average, she uses her albuterol inhaler three times per week, but for the past 10 days, she has been wheezing

both day and night and is using the inhaler three to four times per day. On examination, you note diffuse wheezing and moderate subcostal retractions. Which of the following is the next step in management?
A. Order a chest radiograph to assess for pneumonia.
B. Refer her to an allergist for allergen immunotherapy.
C. Start an oral leukotriene modifier.
D. Start a low-dose inhaled corticosteroid.
E. Start a short course of systemic corticosteroids.

The response options for statements 11 and 12 are the same. You will be required to select one answer for each statement in the set.

A. Short-acting inhaled β2-agonist as needed for symptom relief plus daily medium-dose inhaled corticosteroid
B. Short-acting inhaled β2-agonist as needed for symptom relief
C. Short-acting inhaled β2-agonist as needed for symptom relief plus daily long-acting β2-agonist.
D. Long-acting inhaled β2-agonist as needed for symptom relief plus daily low-dose inhaled corticosteroid
E. High-dose inhaled corticosteroid as needed for symptom relief

For each description of a patient with asthma, select the most appropriate initial pharmacologic therapy.

1. A 8-year-old girl with daily wheezing and nighttime symptoms two times per week.
2. A 4-year-old boy with transient mild wheezing two to three times per year associated with cold symptoms.

Answers and Explanations
1. The answer is A [III.B]. Croup is the most common cause of acute stridor with cough in toddlers, and parainfluenza virus causes the majority of these infections. Foreign body aspiration may cause stridor or cough and should be considered as a cause, because in as many as 50% of foreign body aspirations, choking is not witnessed. Corticosteroid therapy is the treatment of choice for symptomatic croup. An anterior–posterior radiograph of the neck will show a “steeple sign” characteristic of subglottic narrowing, while a “thumbprint sign” on lateral neck radiograph is associated with epiglottitis. Antibiotics are not indicated for croup.
2. The answer is C [III.E.3–6]. This patient’s clinical features are consistent with bronchiolitis, a viral lower respiratory tract infection. Supportive care is the most effective management. Respiratory syncytial virus is the most common cause of bronchiolitis. Chest radiography usually demonstrates hyperinflation and atelectasis. Chlamydia trachomatis pneumonia generally occurs in a young infant, 1–3 months of age, and would be very unlikely in a 5- month-old infant. Antibiotics are not effective for viral bronchiolitis. Bronchoscopy would be indicated if foreign body aspiration was suspected, which is less likely in a 5-month-old.
3. The answer is E [Table 9-2 and III.F.3]. The most common cause of pneumonia in older children and adolescents is atypical infection with Mycoplasma pneumoniae and Chlamydia pneumoniae. Pneumonia in immunocompromised patients may be caused by Pneumocystis jiroveci. Although pneumonia as a result of Staphylococcus aureus may occur in an adolescent, the patient would be more acutely ill. Group B streptococcus is an organism unique to the neonatal period. Bordetella pertussis is the cause of whooping cough.
4. The answer is B [IV.B.3–5, IV.B.7, and Figure 9-3]. The likely diagnosis is cystic fibrosis (CF). Lung disease eventually develops in all individuals with classic CF; the lungs are initially colonized with Staphylococcus aureus and subsequently with mucoid Pseudomonas aeruginosa. Neonates with CF may present with meconium ileus, an impaction of inspissated meconium that causes congenital intestinal obstruction. Pulmonary function studies demonstrate decreased respiratory flow rates and air trapping, consistent with obstructive lung disease early in the disease process. Later, restrictive lung disease patterns are present. The autosomal recessive inheritance of CF means that each subsequent sibling has a 25% chance of having the disease. Pathophysiology involves an altered ion-channel regulator (CFTR) protein, resulting in abnormal sodium and chloride transport in epithelial cells, which can cause a hyponatremic, hypochloremic metabolic alkalosis.
5. The answer is D [IV.B.7]. Pancreatic insufficiency and malabsorption are very common and require pancreatic enzyme replacement and the administration of fat-soluble vitamins (vitamins A, D, E, and K). Nutritional support is very important, as patients commonly have failure to thrive with difficulty gaining weight, for which high-calorie diets are prescribed. Broad-spectrum antibiotics should be used for the treatment of pulmonary exacerbations. Other effective treatment modalities in cystic fibrosis are mucus-altering agents with aggressive pulmonary toilet, including chest physical therapy to help expectorate thick mucus.
6. The answer is A [IV.C]. Prematurity and barotrauma from prolonged mechanical ventilation are significant risk factors for the development of bronchopulmonary dysplasia or chronic lung disease of infancy. These patients are at risk for significant deterioration with respiratory syncytial virus infections during their first year of life, and would therefore benefit from palivizumab (RSV monoclonal antibody) prophylaxis. To meet their metabolic demands and facilitate growth, patients require very high caloric intakes. Pulmonary disease improves with time and lung growth, although chest radiographs may remain abnormal for years. Development is often delayed in children with chronic lung disease.
7. The answer is B [IV.E]. This patient had an apparent life-threatening event (ALTE) now more

often referred to as a brief resolved unexplained event (BRUE). The evaluation of an ALTE should include attempts to identify an underlying cause, and workup may include an electroencephalogram to rule out a seizure disorder, an electrocardiogram to rule out a dysrhythmia such as long QT syndrome, electrolytes, a barium esophagogram or pH probe study to rule out gastroesophageal reflux disease, and a sleep study. It might be useful to observe the infant while feeding in the emergency department. The effectiveness of home apnea monitor in preventing sudden infant death syndrome has not been established. In addition, no definitive relationship between ALTE and sudden infant death syndrome (SIDS) has been established. To prevent SIDS or ALTE, co-sleeping is not recommended. SIDS prevention includes firm bedding and sleeping supine.
8. The answer is C [III.A.7]. This patient’s presentation with fever, toxic appearance, muffled speech, tripod positioning when seated, drooling, and neck hyperextension all suggest epiglottitis as a possible diagnosis. Epiglottitis is now a very uncommon infection as a result of the successful immunization of children against Haemophilus influenzae type b; however, epiglottitis may still occur secondary to infection with streptococcal and staphylococcal species. Management includes avoidance of excessive stimulation, such as examination of the pharynx with a tongue depressor, because this may induce respiratory distress. Evaluation of the airway and intubation by experienced personnel in a controlled setting are necessary. Racemic epinephrine is not effective in epiglottitis. A “steeple sign” on a radiograph of the neck is consistent with the diagnosis of croup, not epiglottitis (which demonstrates a “thumbprint sign” on lateral radiograph of the neck). Bacterial tracheitis presents with fever and stridor (rather than a muffled voice), and drooling and neck hyperextension are unlikely to be present.
9. The answer is B [III.F.3, III.F.4.c, and Table 9-2]. This patient’s clinical features point to a likely diagnosis of pneumonia secondary to infection with Chlamydia trachomatis, which is a common perinatally transmitted cause of pneumonia in infants 1–3 months of age. Patients are afebrile, have a characteristic staccato-type cough, and may have a history of conjunctivitis (in 50% of cases). Blood cultures are not positive in this infection. Management includes oral macrolide antibiotics. Neither corticosteroids nor mucolytics are effective treatments for C. trachomatis pneumonia.
10. The answer is E [IV.A.7 and Tables 9-4 and 9-5]. This patient presents with an acute exacerbation of her chronic asthma and therefore would benefit from a short course of systemic corticosteroids. Both inhaled corticosteroids and leukotriene inhibitors are effective management options for the prevention and chronic management of asthma, and these agents can be considered for her long-term controller therapy. Allergen immunotherapy may also be beneficial but would not be the initial step in management. Chest radiographs are not routinely indicated for asthma exacerbations.
11. The answers are A and B, respectively [Tables 9-4 and 9-5 and IV.A.7]. Asthma is graded on a severity scale on the basis of the frequency of asthma symptoms during the day and night, and also on pulmonary function testing. The 8-year-old girl’s asthma would be characterized as moderate persistent asthma because of the presence of daily symptoms and nighttime wheezing more often than once per week. The recommended initial treatment for moderate persistent asthma is either a medium-dose inhaled corticosteroid OR a low-dose inhaled corticosteroid with a long-acting inhaled β2-agonist for the controller, AND an inhaled short- acting β2-agonist as needed for the reliever. The 4-year-old boy’s asthma would be characterized as intermittent asthma. Intermittent asthma only needs a short-acting inhaled β2- agonist for symptom treatment without need for a long-term controller. Long-acting β2- agonists should not be used as quick relievers.