Pulmonary Disorders

Inspection

Decreased subcutaneous adipose tissue typical of CF should be noted. The pattern of breathing should always be evaluated with the child disrobed. Any use of the expiratory muscles is abnormal. Suprasternal and intercostal retractions reflect excessive negative pleural pressure and can be seen in normal children with thin chest walls after vigorous exercise. Subcostal retractions are the result of hyperinflated lungs and a flattened diaphragm pulling inward on the chest wall. In advanced lung disease, the use of accessory muscles of inspiration can be noted; the sternocleidomastoid muscle, for example, helps lift the chest (in a “bucket handle” fashion) and increase its anteroposterior diameter, thereby increasing intrathoracic volume. In respiratory muscle fatigue, a pattern of breathing can be observed in which the diaphragm alternates with the intercostal muscles to inflate the lungs. This is known as respiratory alternans, or paradoxical chest wall motion, and is seen as alternating abdominal and chest expansion instead of the usual pattern of simultaneous chest and abdominal expansion. Chest wall deformities such as pectus excavatum or pectus carinatum (see Chapter 18 ) should be noted.

Palpation

Chest palpation is performed by placing the hands on either side of the chest as the patient takes a deep breath. The chest should expand symmetrically; asymmetry can be seen in unilateral pulmonary hypoplasia, mainstem bronchial obstruction, and diaphragmatic paresis. Placing fingertips on the upper abdomen just over the insertion of the rectus muscles into the lower rib cage can reveal subtle use of expiratory muscles in children with peripheral (lower) airway obstruction. Similarly, the anterior lower ribs should be assessed with the fingertips. In infants with obstructive lung disease, the lower ribs can be felt pulling inwards on inspiration. This is the palpable aspect of a subcostal retraction. With the patient’s head in the midline position, the trachea should be palpated at the sternal notch to evaluate for tracheal deviation, as is seen with mediastinal shift. Vocal fremitus should be assessed in patients with suspected pleural fluid accumulation; the vibrations transmitted from the larynx as the child says “99” are diminished when there is an accumulation of air or fluid in the pleural space. Infants and children with tracheomalacia and bronchomalacia often have a palpable vibration in the back. Palpable vibrations in only one hemithorax suggest a partial obstruction of the mainstem bronchus in that hemithorax as seen in bronchomalacia.

Percussion

Percussion of the chest can reveal much more than hyperresonance and dullness over an area of consolidation. Air trapping is the hallmark of small airway disease and results in a depressed position of the diaphragm. Ordinarily the diaphragm can be found just at or slightly below the tip of the scapula when the patient’s arm is at his or her side in children 5 years old and younger. In the patient with hyperinflation, the diaphragm is found several fingerbreadths below the scapular tips. An area of consolidation or pleural effusion results in dullness to percussion. Another disorder causing asymmetry of percussion of the two hemithoraces is diaphragmatic eventration, a congenital lesion in which the diaphragm is replaced with a thin fibrous membrane without contractile properties. Postoperative diaphragmatic paralysis (which may occur following cardiac surgery) can be diagnosed by percussion of the cooperative patient while holding his or her breath at maximal inspiration and at end-expiration.

Auscultation

Auscultation of the pediatric chest requires patience. One often must wait a minute or two for a deep breath in order to appreciate abnormal breath sounds that are not apparent on shallow breathing. Augmenting the expiratory phase with a gentle squeeze of the thorax while listening with the stethoscope may improve detection of expiratory wheezes.

Abnormal (“adventitial”) breath sounds include crackles and wheezes. Wheezes are continuous sounds, whereas crackles (formerly referred to as rales ) are discontinuous . Wheezes and crackles can be inspiratory or expiratory, although crackles are more commonly heard on inspiration and wheezes are more commonly heard on expiration.

Wheezes probably arise from the vibration within the walls of narrowed large and medium-sized airways. In a patient experiencing an acute exacerbation of asthma, the lungs have wheezes in a range of pitches (described as polyphonic, or heterophonous ) with substantial regional differences in auscultation. Patients with central airway obstruction such as tracheomalacia, on the other hand, have a single pitch of wheeze that sounds the same in all lung fields (monophonic, or homophonous) and is heard loudest over the central airway that is obstructed. Foreign bodies can cause a monophonic wheeze that can vary in pitch depending on the degree of obstruction.

Crackles are believed to arise from the popping of fluid menisci within airways. The fine crackles heard in the lungs of patients with interstitial lung disease (ILD) or pulmonary edema may arise from popping open of small airways. Coarse crackles are often audible at the mouth and can be found in CF patients with advanced bronchiectasis. Coarse crackles can also be made by pooled secretions in the central airways.

Other sounds that can be heard include friction rubs, which are creaking sounds heard during both phases of respiration as inflamed pleural surfaces rub over one another. One of the most important abnormal findings in children is the absence of breath sounds over an area of collapse or consolidation.

Extrapulmonary Physical Exam Findings

Digital clubbing may suggest lung disease ( Fig. 17.1 ), although extrapulmonary causes include cardiac, inflammatory, gastrointestinal, hepatic, familial causes, as well as clubbing observed with thyrotoxicosis ( Box 17.3 ). Bronchiectasis from CF or from other chronic infectious causes is the major cause of clubbing among all pulmonary diseases. Digital clubbing in any child with a chronic cough or wheezing warrants a thorough evaluation and investigation to determine the underlying disorder.

The astute pulmonologist will carefully examine the remainder of the patient. The exam should also include evaluation for nasal polyps (see Fig. 17.2 ), which can be associated with CF, triad asthma, or significant atopy. Tonsillar hypertrophy can be associated with obstructive sleep apnea (OSA). An increased second heart sound, or absence of a split-second heart sound, could suggest pulmonary hypertension.

Laryngomalacia

The inspiratory stridor associated with congenital laryngomalacia generally begins within the first week of life, varies with activity, and is more noticeable in the supine position. The obstruction can be caused by prolapse of the arytenoid cartilages or collapse of the epiglottis due to foreshortened aryepiglottic folds. Clinical symptoms may suggest the diagnosis; but if severe, bronchoscopic visualization of airway dynamics by flexible bronchoscopy is a safe and reliable method of excluding other causes of stridor. Parents can be reassured that this entity is self-limited, becomes less marked after 6 to 10 months of age usually with maturity of innervation or of the larynx, and rarely causes serious problems. In a small percentage of patients, obstruction of the larynx can interfere with feeding and cause dysphagia or failure to thrive, and in some infants it can cause cyanosis with feeding. In these cases, surgical treatment (“supraglottoplasty”) may be considered.

Croup

The most common cause of inspiratory stridor in children is infectious croup (acute laryngotracheobronchitis). This disease is most commonly caused by a respiratory virus (parainfluenza, respiratory syncytial, influenza, or rhinovirus), and the patient typically has coryza for 24 to 48 hours before the appearance of croupy cough, hoarseness, and stridor. Occasionally the inflammatory process may spread to the smaller airways and produce wheezing in addition to these symptoms. The “steeple sign” is a characteristic radiographic sign on anteroposterior projections that may be accompanied by marked dilation of supraglottic structures, particularly on lateral films. In most patients, serious airway obstruction does not occur and the disease is self-limited. Acute angioneurotic edema is a less common cause of stridor. In most cases, it results from an allergic reaction and is potentially fatal. Some children with anatomically normal airways suffer recurrent bouts of stridor, usually in the middle of the night, in the absence of signs of viral infection. Treatment for GER is helpful in some patients, suggesting that occult GER can contribute to bouts of recurrent airway obstruction.

Subglottic Stenosis

Narrowing of the subglottic region can be congenital or acquired, such as in subglottic stenosis associated with endotracheal intubation. Congenital subglottic stenosis improves as the child grows older, but narrowing associated with tracheal intubation may require a tracheostomy, particularly if the infant remains dependent on ventilatory support. The degree of subglottic stenosis can be determined by “sizing” of the airway with various sized endotracheal tubes and assessing for leak. Low grade stenosis may be monitored expectantly or amenable to balloon dilation, while higher grade stenosis may require laryngotracheal reconstruction.

Vocal Cord Paralysis

Vocal cord paralysis, either unilateral or bilateral, may be present in the neonatal period, although in the case of unilateral paralysis several weeks may pass before the diagnosis is suspected. A weak or absent cry, hoarseness, inspiratory stridor with or without respiratory distress, and feeding difficulties are usual signs of vocal cord paralysis. Bilateral vocal cord paralysis may be seen with hydrocephalus, myelomeningocele, Arnold-Chiari malformation, or other malformations of the brain. Unilateral and bilateral cord paralyses are observed in patients with abnormalities of the cardiovascular system that are accompanied by cardiomegaly (e.g., ventricular septal defect, tetralogy of Fallot) or that cause abnormalities of the great vessels (e.g., vascular ring, transposition, patent ductus arteriosus). The diagnosis is best made by flexible laryngoscopy under minimal sedation so that vocal cord movement can be examined adequately. Because of a strong association of dysfunctional swallow with vocal cord paralysis, a barium swallow should be performed in suspected cases to assess for aspiration.

Other Disorders of Larynx

Congenital laryngeal or pharyngeal masses can also produce stridor by obstructing the airflow. Although inspiratory stridor may be observed, hoarseness is a more common presenting feature. Laryngeal webs, papillomas, or hemangiomas may all present with ongoing stridor, as well as brassy or dry cough. Hemangiomas of the larynx or trachea may also produce stridor or a brassy or dry cough. Cutaneous or mucosal hemangiomas noted during the physical examination suggest the possibility of additional organ system involvement. Laryngeal webs ( Fig. 17.3 ), cysts, and laryngoceles are quite uncommon and are accompanied by respiratory distress, stridor, feeding difficulties, and cyanosis. Diagnosis is made by bronchoscopy. A foreign body in the pharynx or larynx may also cause stridor. For additional information on stridor, see Chapter 24 .