Parents must understand your terminology, and you must understand theirs (see Chapter 1). What parents describe as a wheeze may, in fact, be stridor. What you call asthma may mean something much more alarming to parents. Do not assume that parents understand what is meant by terms such as wheeze. Be prepared to imitate a wheeze, stridor, or whoop, or ask the parents to imitate the sound they are trying to describe.

Key Point

Establishing whether the child makes the sound on inspiration or expiration may seem easy to you, but many parents have difficulty making that distinction.

Some parents have difficulty recalling the circumstances or triggers that cause or aggravate their child’s respiratory symptoms. This situation occurs frequently in children with asthma. Have a prepared list of common asthma triggers on hand to help them (Fig. 9–1).

FIGURE 9–1 The common triggers of asthma.

Each symptom should be probed until it has been characterized well with respect to timing, aggravating and relieving factors, and associated features. Establish whether the symptoms are acute (less than 3 weeks’ duration); long-standing or chronic (more than 3 months’ duration); or recurrent (with symptom-free intervals of at least 2 weeks’ duration).

These answers help narrow the diagnostic possibilities when dealing with stridor or wheezing. To narrow the diagnostic possibilities further, try to relate symptoms to each other; for example, cough and stridor; cough and wheeze; and cough, wheeze, sputum, and failure to thrive.

Before completing the history, ask the parents and child what they see as the major problem. Parents occasionally bring up concerns they did not mention earlier in the interview. Likewise, do not assume that their concerns are the same as yours; often they are surprisingly different.

Chief complaints

Cough, wheeze, and recurrent infections are the most common complaints arising from respiratory diseases, although parents of younger children may complain that their child has noisy breathing. To characterize the main complaint, you must consider the child’s age, duration of the symptom, timing, aggravating and relieving factors, and the effect of previously prescribed medications.

Begin the history-taking for young children by asking about details of the pregnancy and birth. Ask about a history of maternal infections, drug use, cigarette smoking, and any problems during labor and delivery. The baby’s gestational age, birth weight, Apgar score, and need for resuscitation, oxygen, or assisted ventilation should be documented. Difficulty establishing feedings, episodes of apnea, or any evidence of respiratory distress in the neonatal period may set the stage for respiratory problems later in infancy. Dating the onset of symptoms can help; the closer to birth the symptoms began, the more likely they are due to a congenital disorder. If the child appeared well early in life, ask how old the child was when the symptoms began.

The following sections describe some common complaints and important questions to ask about them during history-taking.

Previous hospitalization

Record the dates and circumstances of previous hospitalizations and treatments. Try to determine whether the hospitalizations resulted from failed medical management at home and whether the parents have sufficient information and the tools required to reduce the frequency of future hospitalizations.

Medications

It is not enough simply to list the medications given to a child. Dosages and timing of administration are essential information. Try to distinguish between the medication regimen the child is supposed to be following and what the child actually takes. Remember that compliance with regularly prescribed medications in children is very poor. Ask, “Many children have trouble remembering to take their medications—does this ever happen to you?” If the child replies in the affirmative, ask, “How many times a week do you remember to take your medications?”

For patients using home nebulizers, record details of how the medications and diluent are mixed and administered. Inquire about the particular devices being used to deliver aerosol medications and the technique used (i.e., open-mouth versus closed-mouth technique when using metered aerosols), or if a spacer device is used (e.g., Aerochamber), which one. Ask about adverse effects from medications. Some children experience adverse effects from normal therapeutic doses of bronchodilators.

Key Point

It is not sufficient simply to ask whether the child’s technique in using a particular device is satisfactory. Observing the child while he or she uses the device is essential.

Immunizations

Inquire whether the child has received influenza or pneumococcal vaccines in addition to his or her regularly scheduled immunizations.

Smoking

Ask who smokes in the child’s environment and how much. The history of smoke exposure applies not only to the home and the family car but also to friends and relatives who visit the home and visits to relatives or friends in their homes. Does smoke exposure aggravate the child’s respiratory symptoms? Ask the child how he or she feels when exposed to smoke. Parents who smoke often say their child does not have respiratory symptoms when exposed to their cigarette smoking, but the child may tell quite a different story. Remember, children as young as 10 years may smoke cigarettes; always ask about this possibility out of parents’ hearing.

Environmental factors

Ask about the effects of exposure to specific home environments and inhalants—for example, moldy basements, dusty areas, sprays, perfumes, and substances the parents may use in their occupations—because they can trigger symptoms. Ask about symptoms from exposure to (1) grass, trees, and pollens; (2) dust and chalkboard dust at school; and (3) pets at home or in the homes of family or friends. Regularly recurring symptoms during a particular season may provide the essential tip-off to allergies; for example, the child may have symptoms related to trees in spring, grass in summer, and ragweed in autumn. Symptoms occurring at school sometimes can be difficult to sort out, to the frustration of many parents.

Family history

Pets

List all pets with which the child comes into contact, both inside and outside the home. Ask whether the child has any symptoms when such exposures occur, and describe examples of symptoms, such as itchy eyes or nose. Not infrequently, a child admits to having symptoms upon being exposed to the pet of a neighbor or relative but not to his or her own pet.

Key Point

Parents sometimes neglect to mention a pet that does not come into the house, such as an outdoor cat or dog, or they overlook exposure to pets at the homes of neighbors or relatives or at school (e.g., the pet rabbit or guinea pig in the nursery school classroom).

Exercise-related symptoms

The relationship between increased physical activity and respiratory symptoms is important. Toddlers with asthma often cough when they are excited or when they are tickled. Ask about symptoms associated with normal activities, such as running or bike riding, during school recess, or when participating in sports, and particularly during cooler weather in the fall and winter. Rather than asking parents whether their child has symptoms during gym class in school, ask the child what happens when he or she runs around the gym at school. Sometimes, the previously undiagnosed asthmatic patient replies, “I cough.” For older children, the type of exercise that triggers symptoms is important. Activities such as cross-country running, soccer, competitive basketball, hockey, and ice skating, which do not allow for a rest period, often can aggravate asthma, particularly if carried out in cold, dry air. Ask children previously diagnosed as having asthma whether they take any medication before, during, or after exercise, and if so, whether it prevents or reduces the symptoms.

School absenteeism

Parents may underestimate or overestimate the amount of school time a child misses because of respiratory symptoms. Brief absences often are forgotten. Checking the school records may give you a more accurate picture of absenteeism. Ask the parents to obtain the information or, with their permission, contact the school.

Allergies

When eliciting a history of allergies, distinguish between unequivocal clinical reactions to specific allergens and the results of allergy skin testing. When parents volunteer a list of items to which the child is allergic, they often are merely reiterating reported positive results of previous skin tests, which may or may not reflect clinical hypersensitivity. Ask the parents whether they have noticed symptoms whenever the child is exposed to any of the items for which he or she had a positive skin test response. Ask about cough, wheezing, symptoms of allergic rhinitis or conjunctivitis, laryngeal edema, and hives. For serious allergic reactions, such as anaphylaxis, ask whether adrenaline (e.g., an EpiPen) has been prescribed and whether it has been used.

Allergic rhinitis

Because many parents are unfamiliar with the terms allergic rhinitis and hay fever, ask instead about whether the child has an itchy nose, a runny nose, displays the classic “allergic salute” (i.e., repeatedly rubbing the tip of the itchy nose with the palm or back of the hand) (Fig. 9–2), or has fits of sneezing. Establish whether any of these symptoms occur seasonally or year-round. Elicit the specific factors triggering these symptoms and the treatments that have been tried.

FIGURE 9–2 The “allergic salute.” The child repeatedly rubs the tip of the itchy nose with the palm or back of the hand.

Ear, nose, and throat

Recurrent otitis media, chronic otitis media with effusion, and sinus involvement often appear with respiratory symptoms in allergic children and in children with ciliary dysfunction or immunoglobulin deficiencies. Ask about snoring and mouth breathing. Curiously, adults are much less tolerant of snoring in children than in themselves or their spouses!

Eczema

Parents usually are aware of overt eczema, but they may forget to mention dry skin or small patches of eczema, particularly dry skin behind the ears, in the atopic child. List past treatments for this problem.

Croup

Croup is a viral infection of the larynx, trachea, and bronchi. If parents are unfamiliar with the term croup, they usually will recognize the symptom pattern, which consists of a harsh, barking cough and hoarse voice occurring at night, sometimes preceded by 1 or 2 days of upper respiratory symptoms (coryza). Spasmodic or recurrent croup occasionally occurs without any obvious preceding respiratory infection. The previously well child suddenly awakens during the night with a harsh cough like a dog barking, a hoarse voice, and inspiratory stridor. Symptoms often improve in a cool, moist atmosphere but may recur during the next few nights. Some children continue to have recurring bouts of croup during early childhood, and asthma later develops.

Gastrointestinal symptoms

Ask whether the child eats poorly or, alternately, is ravenous. Has the child had normal weight gain or weight loss or displayed failure to thrive? Inquire about previous growth measurements and determine the child’s growth pattern. Ask about swallowing difficulties (such as choking while eating or drinking) and symptoms of gastroesophageal reflux, as well as rectal prolapse (an important clue to CF), abdominal pain, stool frequency, and the appearance and odor of stools. A child with oily, foul-smelling stools and failure to gain weight satisfactorily despite a huge appetite usually has CF.

Key Point

When parents report that their child tastes salty when kissed, the youngster must be investigated for cystic fibrosis.

Unusual infections

Always note unusual or persistent infections; for example, a history of Pseudomonas cultured from the sputum suggests a diagnosis of CF. Pay attention to (1) recurrent infections involving the ear, nose, and throat, skin, or respiratory tract and (2) troublesome abscesses, which may suggest an underlying immunologic deficit. Ask about previous immunizations and any unusual reactions to them. Inquire about recent travel if an unusual infection is suspected.

Family attributes

The summary of the respiratory history also should include details regarding the family’s beliefs about and knowledge of the diagnosis of the child’s problems. Try to determine family strengths, weaknesses, coping abilities, and parental education, and inquire about financial resources and employment. Exercise caution when inquiring into such sensitive areas, particularly when meeting a family for the first time. The success or failure of your future management of the child’s problems may depend on the sensitivity you demonstrate and the rapport you establish during this part of the evaluation.

Approach to the Physical Examination

Begin the physical examination with observations as you take the history, before formally examining child; watch for the allergic salute, and listen for noisy breathing and the quality of the child’s cough.

A complete examination of the respiratory system of an infant or young child often is best accomplished with the child sitting in the parent’s lap (Fig. 9–3). Having older children and teenagers sit on an examining table is best. Although the order in which the examination is performed is not crucial, it should be complete. Forgetting to examine the child for clubbing or to listen to the child’s cough are major omissions. Use a pediatric stethoscope when examining infants, because the diaphragm and bell of an adult stethoscope often are too large to be used with infants.

FIGURE 9–3 Most of the physical examination of a young child is best accomplished with the youngster sitting on the parent’s lap.

Many aspects of respiratory examination and findings in a child resemble those in an adult, except for the following important differences:

1. Normal respiratory rates are faster in infants and children (Table 9–1).

2. Compliance of the younger child’s chest wall is markedly greater, as amply demonstrated by the indrawing associated with croup and bronchiolitis.

3. Respiratory sounds (noises) are readily transmitted to the child’s thorax from the upper airway; indeed, the air-filled thoracic cage acts as an amplifier for breath sounds.

TABLE 9–1 Normal Respiratory Rates in Children Who are Awake

Age (years)	Respiratory Rate (breaths/min)
0–1	25–40
1–5	20–30
5–10	15–25
10–16	15–20

Cyanosis

Examine the skin of the extremities, tongue, and mucous membranes for cyanosis, and distinguish between peripheral and central cyanosis. Central cyanosis indicates cardiorespiratory disease. Because central cyanosis occurs at different levels of arterial oxygen saturation according to the amount of total hemoglobin present, it is not a reliable early sign of hypoxemia.

Nasal flaring

You can easily overlook flaring of the alae nasi if you do not look for it specifically. Nasal flaring is a nonspecific but important sign of respiratory distress, probably reflecting increased work of breathing and dyspnea.

Ears, nose, and throat

A detailed examination may uncover serous otitis media, allergic shiners, inflamed nasal mucosa in the child with allergies, or, rarely, nasal polyps in the child with CF. Chronically draining ears, particularly following the insertion of tympanostomy tubes, may indicate a ciliary abnormality.

Use of accessory muscles

When airway obstruction or pulmonary disease is present, the child uses accessory muscles, mainly the sternocleidomastoid, scalene, and abdominal muscles, to aid respiration.

Retractions

When present in children, retractions usually involve soft tissue (suprasternal, supraclavicular, or intercostal) but can be in the lower sternum in younger children and in infants with compliant chest walls. Retractions result from differences between intrathoracic and atmospheric pressures in airway obstruction or from increased lung stiffness. Subcostal or lower costal retraction, whether it is chronic or of acute onset, usually is associated with flattening of the diaphragm due to air trapping and pulmonary hyperinflation. When it contracts, the flattened diaphragm pulls on the chest wall at the site of its attachments, creating a groove.

Chest wall shape and deformity

Observe whether the chest configuration is abnormal (Figs. 9-4 to 9-6); remember that infants’ chests are rounder than those of older children because of the more horizontal position of the ribs. Chronic, diffuse, small airway obstruction with air trapping produces an abnormally rounded or “barrel-shaped” chest with a greater anteroposterior diameter (see Fig. 9–4). This finding often is associated with subcostal or lower costal indrawing. Note bony thoracic deformities, such as pectus excavatum (funnel chest) (see Fig. 9–5) or pectus carinatum (pigeon breast) (see Fig. 9–6). As an isolated finding, pectus excavatum seldom is associated with any respiratory abnormalities. In some cases, pectus carinatum may be an isolated finding, but in other cases, it may signal a chronic cardiorespiratory problem. Occasionally, other chest wall deformities are found, which are either congenital or a result of thoracic surgery.

FIGURE 9–4 Increased anteroposterior diameter (“barrel chest”) and lower costal retraction in a child with poorly controlled asthma.

FIGURE 9–5 Pectus excavatum (funnel chest). For most children, this problem is purely cosmetic.

FIGURE 9–6 Pectus carinatum (pigeon-breast deformity) usually is not associated with cardiopulmonary disease.

Chest-abdominal movement

Carefully observe chest movement from the child’s side to confirm that the two sides of the chest move equally. By observing a child’s breathing with the youngster in both a standing and a supine position, you can easily see the relative contributions of the chest and abdomen during respiration. Children have more abdominal movement during respiration than do adults.

During sleep, further changes occur in the activity of respiratory muscles. During the rapid eye movement sleep cycle there is intercostal muscle inhibition and, occasionally, some paradoxical movement of the chest and abdomen, which is particularly noticeable in children with obstructive sleep apnea.

Kyphoscoliosis

Look at the spine’s configuration. Marked scoliosis affects the shape of the thoracic cage and may impede pulmonary function (Fig. 9–7).

FIGURE 9–7 Distortion of thoracic shape as a result of scoliosis.

Respiratory rate

An abnormally fast or slow respiratory rate may reflect a disturbance in the respiratory or cardiovascular system or in the central nervous system (CNS) control of breathing. Measure the respiratory rate by counting for a full minute. (See Table 9–1 for normal values at different ages.)

Depth of respiration

Deep breathing (hyperpnea) and shallow breathing (hypopnea) are appreciated easily if they are pronounced but can be missed if they are subtle.

Ease of respiration

Estimate the ease of respiration by observing whether the child appears short of breath (dyspneic), is distressed when lying supine (orthopneic), has retractions of soft tissue or sternum, has flaring of the alae nasi, or uses accessory muscles of respiration. Labored respiratory efforts reflect the increased work of the respiratory muscles and often are caused by airway obstruction.

Rhythm of respiration

Although several abnormal respiratory rhythms can reflect CNS disturbances, note particularly the presence of sleep apnea, and distinguish between central and obstructive types (this distinction requires observation while the child is asleep). Central apnea occurs when there is no airflow and no apparent respiratory effort. In obstructive apnea, airflow may be completely or partially reduced in association with vigorous inspiratory efforts and paradoxical movements of the rib cage and abdomen.

The duration of apnea considered to be abnormal varies with age. Apnea lasting up to 20 seconds is normal in premature infants, whereas shorter apneic periods may be significant in the older child. The diagnosis of obstructive sleep apnea syndrome should be considered in a child with partial or complete airway obstruction during sleep, which manifests as snoring and sleep disturbance, is associated with documented hypoxemia and hypercarbia, and results in failure to thrive, cor pulmonale, or neurobehavioral disturbance. Periodic breathing in infants, particularly premature babies, consists of two apneic periods of 3 seconds or more within 20 seconds of each other.

Finger clubbing

Inspect the lateral aspect of the finger and the angle formed at the skin-nail junction on the dorsal surface of the terminal phalanx. Finger clubbing (Fig. 9–8) results from a proliferation of nail bed tissue that raises the nail’s base. Gross clubbing is obvious, but subtle degrees of clubbing are easily missed. Clubbing is seen in children with CF, but it also can occur in children with other respiratory, cardiac, and gastrointestinal disorders.

FIGURE 9–8 A mild but significant degree of finger clubbing. Inspection must be made from the lateral aspect of the fingers.

Key Point

Always conduct a careful search for serious disease in the child with clubbing.

Cough

Familiarize yourself with the characteristics of different types of cough, and become adept at describing the cough. Characterizing the sound of a child’s cough is a neglected aspect of the physical examination. If the child has not coughed during the examination, ask him or her to do so. Gently pressing on the trachea in the suprasternal notch sometimes elicits a cough in a younger child.

Table 9–2 lists some common and some not so common respiratory illnesses and the types of cough associated with them.

TABLE 9–2 Illnesses and Associated Coughs

Illnesses	Cough	Comments
Bronchitis	Initially dry; after a few days, may become loose and rattling	Produces a small amount of sputum that is usually swallowed; occasionally, the sputum is thick and yellow, but this finding does not always indicate secondary infection
Asthma	Classic cough is dry, “tight,” and occasionally wheezy	Some children produce abundant secretions with a wet cough; coughing may be spasmodic, occur mainly at night, and be associated with vomiting; throat clearing that parents believe to be a habit may be an early manifestation of asthma; a wet asthma cough can mimic a cystic fibrosis cough
Croup (acute laryngotracheo-bronchitis)	Sounds like the “bark” of a seal	Sudden onset; the child goes to bed well or with a slight cold; often associated with an inspiratory stridor and a hoarse voice
Pertussis	Spasmodic, choking, repetitive cough with no inspiration during coughing spasms	Associated with eye tearing, profuse secretions, and facial suffusion; spasm punctuated by sudden crowing inspiration (the “whoop”) or vomiting
Pulmonary inhalation	May be dry or loose; often associated with lower airway obstructions	More commonly heard in children with swallowing incoordination or developmental delay; can be similar to the cough of asthma, bronchitis, or bronchiolitis
Chlamydia pneumoniae pneumonia	Typically paroxysmal, dry, and staccato (with a short inspiration between coughs), unlike pertussis	Usually occurs in young infants
Tracheomalacia	Has loud characteristic brassy or vibratory sound, reflecting its tracheal origin	When associated with coarse inspiratory and expiratory stridor, or an inspiratory stridor and an expiratory wheeze, the cough virtually pinpoints the diagnosis
Psychogenic	Uncommon, but not rare, cough; sounds like the loud “honk” of a Canada goose	Remarkably, this cough never occurs during sleep

Noisy breathing

Pay careful attention to any sounds emitted by the child while he or she breathes. See Table 9–3 for a full description of these sounds.

TABLE 9–3 Respiratory Noises

Noise	Quality	Comments
Snoring	Inspiratory noise of irregular quality	Produced by partial obstruction of the upper respiratory tract, usually in the region of the naso-oropharynx
Stridor	Continuous, usually harsh inspiratory sound	Caused by extrathoracic airway obstruction; may be heard on expiration if obstruction is in the subglottic area or trachea, where the sound resembles a wheeze
Wheeze	Continuous sound with musical quality heard mainly during expiration; often a shorter sound on inspiration	Indicates intrathoracic airway obstruction; results from dynamic compression of large central airways from either peripheral or central airway obstruction
Grunting	Episodic, short expiratory sound	Caused by partial closure of the glottis during expiration
Rattly breathing	Coarse, irregular sound heard mainly during inspiration; rattles can be felt through hands placed on the chest	Indicates secretions in the trachea or major bronchi

Palpation

Position of the Trachea

You can accurately assess the position of the trachea in the suprasternal notch by using two fingers when examining older children and one finger for younger children (Fig. 9–9). Tracheal shift indicates that the mediastinum has shifted, signifying either change in volume or pressure in one hemithorax. The mediastinum can be either pushed or pulled to one side, depending on the location and nature of the abnormality. Other aspects of the physical examination usually shed light on the underlying problem, so do not rush to order imaging studies when you detect tracheal shift.

FIGURE 9–9 Palpating tracheal position. Use two fingers in older children (A) and one finger in younger children (B).

Chest Expansion

It is seldom necessary to estimate chest expansion in children by palpation because this parameter usually can be approximated visually.

Vocal Fremitus

Palpating for vocal fremitus over an area of consolidation is easier in adults than in children, but it can be done in older children.

Pulsus Paradoxus

Pulsus paradoxus describes the fluctuation in systemic arterial pressure that occurs with normal respiration. Arterial pressure falls during inspiration and rises in expiration because of the effect of right ventricular preload and the greater force required by the left ventricle to maintain the previous arterial pressure (left ventricular afterload). Using a blood pressure cuff and stethoscope, note the difference in systolic blood pressure between the pressure at which the sporadic faint pulse sounds are first heard and the pressure at which all the sounds are first heard.

It often is difficult and usually unnecessary to try to correlate the pulse sounds with the phase of respiration, particularly in a child with tachypnea. In most normal children, the pulsus paradoxus is less than 5 mm Hg. Severe airway obstruction, pericardial effusion, or constriction can cause pulsus paradoxus of greater than 20 mm Hg. Inspiratory retractions and use of accessory muscles are obvious when airway obstruction is this severe, and it has been noted that pulsus paradoxus can be absent in as many as one third of patients with severe obstruction.

Subcutaneous Emphysema

The presence of subcutaneous air over the chest wall or up into the neck, which is felt as a crackling under the skin on palpation of the neck or chest, indicates an air leak and is usually associated with pneumomediastinum, which can be confirmed by chest radiograph. Pneumothorax may or may not be present but should be investigated because of its potential seriousness.

Percussion

In children, as in adults, you can use chest percussion to detect dull, flat, or hyperresonant areas and to locate the liver’s position and size. An area of consolidation may sound dull to percussion; a pleural effusion, flat; and a hyperinflated area, hyperresonant. Asymmetric findings on percussion are more obvious because a normal hemithorax can be compared with the abnormal side. With time and experience, you will find that the normal percussion note in the child becomes more familiar and that you can more readily detect subtle changes. Useful percussion of the chest in infants and young children calls for much lighter percussion than is used in older children or adults. In younger persons, as much or more can be learned from the feel of the percussion note as from its audible sound.

The chest radiograph has replaced percussion for precise location of the position and size of the heart, but percussion is still useful for detecting the upper and lower liver margins to determine whether a child has true hepatomegaly or whether the liver has simply been pushed downward by a hyperinflated lung.

Auscultation

Auscultation over each segment of both lungs is neither practical nor necessary in most circumstances. You should know the surface anatomy of the pulmonary lobes and listen over each one (Fig. 9–10).

FIGURE 9–10 Surface anatomy of the pulmonary lobes and suggested auscultation sites (indicated by solid circles).

Key Point

In general, auscultation is performed with the stethoscope diaphragm, because breath sounds tend to be higher pitched than heart sounds.

Always compare the two sides of the chest during auscultation, characterize the breath sounds, and then listen for adventitious sounds. Determine whether the breath sounds are normal, increased, or decreased in intensity, and describe their quality. Always note any asymmetric differences. The closer the stethoscope is to a larger airway, the more audible and tubular the note will be; these differences are best appreciated by listening during expiration. Always avoid auscultating through clothing. The bronchial breath sounds heard over an area of consolidation or atelectasis illustrate the improved transmission of sound through solid or airless tissue (Table 9–4). Note any adventitious or “extra” sounds, using the descriptions in Table 9–5.

TABLE 9–4 Breath Sounds

Sound	Quality	Comments
Tracheal	“Tubular,” high pitched	Heard during inspiration and expiration
Bronchial	Has a tubular quality that is less pronounced than in tracheal breath sounds	Heard on inspiration and expiration
Bronchovesicular	Pitched slightly higher than vesicular breath sounds	Heard mainly on inspiration, but an early low-pitched note may be heard on expiration
Vesicular	Softer, lower pitched	Heard in axillary area and lung bases; heard on inspiration and little heard on expiration

TABLE 9–5 Adventitious Sounds in the Chest

Sound	Description	Comments
Crackles/crepitations (formerly known as rales)	Short, crackling, nonmusical sounds heard on inspiration or expiration	Fine inspiratory crackles due to alveolar or bronchiolar disease that has allowed collapse of the peripheral airway, leading to a crackle as it gradually opens and a thin film of fluid bursts; coarser inspiratory or expiratory crackles may arise from air bubbling through mucus in larger airways, the auscultatory finding in a child with rattly breathing
Wheezes	Continuous musical, usually expiratory sounds produced by air moving past an obstruction or a narrowing airway	Distinguishing between high-pitched (sibilant) and low-pitched (sonorous) wheezes is probably unnecessary because it may reflect differences only in flow rates; wheezes arise from larger bronchi because air velocity in smaller airways is too slow to produce a musical sound
Friction rub	Harsh grating sound synchronous with respiration, indicating friction on movement between the two layers of pleura	Usually easily distinguished from a pericardial friction rub

Key Point

A child’s vocalization often can be heard clearly when the stethoscope is placed over an area of consolidation or atelectasis.

Differentiating extrathoracic from intrathoracic airway obstruction

Localizing the site of an obstruction in the respiratory tract can be both challenging and rewarding in children (Fig. 9–11). Remember that although the airway extends from the nose to the bronchioles, the anatomic site of an obstruction can be determined using the following simple clinical guidelines:

1. Extrathoracic (i.e., upper respiratory tract) obstructions are associated with inspiratory stridor, and intrathoracic obstructions are associated with expiratory wheeze.

2. Stridor is mainly an inspiratory sound, whereas wheeze is an expiratory sound. Holding the bell end of the stethoscope about 1 inch (2.5 cm) from the child’s mouth can help you distinguish between these sounds (Fig. 9–12).

3. Predominantly suprasternal and lower sternal retractions usually suggest extrathoracic obstruction.

4. Stridor and hoarseness indicate an obstruction in the larynx; when they are associated with a cough, the trachea is involved.

5. Stridor that worsens over weeks or months suggests a progressive airway obstruction.

6. Subcostal or lower costal retractions and an increased anteroposterior diameter of the chest reflect air trapping and a flattened diaphragm resulting from small airway obstruction.

7. A high-pitched monophonic wheeze that is heard mainly over one hemithorax usually indicates an obstruction in a single larger airway.

8. The symptoms must be identified as being either acute or chronic so that the diagnostic possibilities may be narrowed. Nocturnal onset of acute stridor with a barky cough and hoarse voice is most likely croup, whereas chronic stridor from early infancy in an otherwise healthy child usually indicates laryngomalacia and less often signifies congenital subglottic stenosis or some other anomaly in the region of the larynx or upper trachea.

FIGURE 9–11 The common sites of upper (extrathoracic) airway obstruction and lower (intrathoracic) airway obstruction and examples of each.

FIGURE 9–12 Holding the bell end of the stethoscope near the child’s mouth is a handy trick for differentiating stridor (extrathoracic airway obstruction) from wheeze (intrathoracic obstruction). This maneuver should precede auscultation of the chest, because it helps differentiate abnormal bronchopulmonary noises from transmitted and amplified upper airway noise.

Tracheomalacia and Laryngomalacia

Tracheomalacia is a term used when a portion of the trachea is unusually soft (Fig. 9–13). Tracheomalacia usually occurs in children with esophageal atresia and tracheoesophageal fistula, but it also can arise as a result of a vascular compression, usually by an anomalous artery. Tracheomalacia sometimes occurs without any associated abnormality. The soft area of the trachea is more collapsible and causes a rather coarse inspiratory stridor. A vibratory expiratory stridor, or occasionally a wheeze, often is heard in these patients. When the child coughs, the more easily collapsible soft area of the trachea generates a loud, brassy sound, best described as the “supermarket cough” because parents remark that their child draws immediate attention from other shoppers when they hear the loud, harsh cough. Full evaluation, including fluoroscopy and bronchoscopy, may be required to establish the exact nature of the disorder and to guide management. A loud vibratory cough without stridor or any other associated symptoms occasionally is heard in some older children and is of no clinical significance.

FIGURE 9–13 Bronchoscopic view of the trachea in a child with tracheomalacia.

Tracheomalacia and laryngomalacia are sometimes confused, but the distinction can be made easily on clinical grounds. Laryngomalacia (also known as infantile larynx and congenital laryngeal stridor) is the most common cause of chronic stridor in infancy. It is a supraglottic airway obstruction resulting from laxity of the soft tissue above the vocal cords (in the aryepiglottic folds), which fall inward on inspiration, partially obstructing the airway. Noisy stridor (“crowing”) develops soon after birth, but by 12 to 18 months, the noise disappears. There is no associated cough, feeding difficulty, or failure to thrive. Because laryngomalacia is an extrathoracic airway obstruction, the characteristic feature is a variable high-pitched crowing inspiratory stridor that many parents find alarming, at least initially. Typically, the loudness of the stridor varies with the baby’s position: it worsens when he or she is supine and in the presence of upper respiratory infections and improves when he or she is prone. There may be some associated sternal retraction, but the infant is rarely distressed.

Direct examination of the larynx is required only in the presence of atypical features (Fig. 9–14). In most cases, the only treatment required for laryngomalacia is reassuring the parents about the condition’s benign, self-limited nature. Parents should be told that the noise will get worse when the child has respiratory infections. Because laryngomalacia and tracheomalacia are quite distinct in both origin and clinical presentation, the use of the term laryngotracheomalacia is inappropriate.