Wheezing


CHAPTER 1 WHEEZING


DUSTIN R. HAFERBECKER


DEFINITION OF THE COMPLAINT


Noisy breathing in infants is a common presenting complaint. The first step toward formulating a differential diagnosis is to characterize the type of sound heard. Stertor, a low-pitched rattling inspiratory noise, is caused by obstruction of airway above the level of the larynx. It is frequently heard in infants with nasal congestion and is often of little consequence. Stridor, a harsh, high-pitched respiratory sound typically heard on inspiration, often indicates laryngeal obstruction. Wheezing, a musical sound heard on expiration, is caused by partial obstruction of the lower airway. In young children, sometimes expiratory noises cannot be easily distinguished from inspiratory ones, and at times both may be present. Among these causes of noisy breathing, wheezing is the most common of clinical significance.


COMPLAINT BY CAUSE AND FREQUENCY


The causes of wheezing in childhood vary by age (Table 1-1) and may also be grouped in categories based on the following criteria: (1) Anatomic (extrinsic or intrinsic to the airway), (2) Inflammatory/Infectious, (3) Genetic/Metabolic, or (4) Miscellaneous causes (Table 1-2).



TABLE 1-1. Causes of wheezing in childhood by age.


Image



TABLE 1-2. Causes of wheezing in childhood by mechanism.


Image


CLARIFYING QUESTIONS


A thorough study of the child’s history is essential to arrive at an accurate diagnosis in a child who presents with wheezing. Consideration of age at onset, course and pattern of illness, and associated clinical features provides a useful framework for creating a differential diagnosis. The following questions may help provide clues to the diagnosis:


What was the age at onset of wheezing?


—Onset at birth or during early infancy suggests congenital structural abnormalities. Congenital diaphragmatic hernias are usually detected on prenatal ultrasound. Vascular rings and aberrant vessels can cause wheezing or other respiratory symptoms early in life. Infants <2 years of age are more susceptible to lower respiratory infection, such as bronchiolitis, whereas adolescents are more likely to have asthma or infection caused by atypical bacteria, such as Mycoplasma pneumoniae.


Is the wheezing a new onset or recurrent?


—The initial episode of wheezing in a previously healthy infant in conjunction with symptoms of upper respiratory tract infection usually indicates bronchiolitis. A sudden onset of wheezing is also characteristic of anaphylaxis; particularly in the presence of urticaria, stridor, or pertinent environmental exposures. Recurrent episodes of wheezing may suggest gastroesophageal reflux. However, if precipitated by upper respiratory infections, recurrent wheezing may suggest reactive airways disease. Recurrent wheezing or “difficult to control asthma” should lead to a consideration of cystic fibrosis, immotile cilia syndrome, recurrent aspiration, immune deficiency, or anatomic abnormalities.


Is the wheezing episodic or persistent?


—Persistent wheezing suggests mechanical obstruction from a variety of causes, such as airway foreign body, congenital airway narrowing, or external compression by a mediastinal mass or vascular anomaly.


Was the episode of wheezing preceded by choking or gagging?


—Aspiration of a foreign body is sometimes associated with the sudden onset of symptoms after gagging or choking. Foreign body aspiration is most common in children between the ages of 1 and 4 years. Symptoms depend on the size and location of the foreign body. The wheezing may be unilateral and secondary bacterial infection may occur.


Was the wheezing preceded by upper respiratory tract infection?


—Antecedent upper respiratory tract infection is suggestive of an underlying inflammatory or infectious etiology.


What is the child’s weight and height?


—Features suggestive of cystic fibrosis include failure to thrive, steatorrhea, or recurrent infections.


Is there a history of recurrent bacterial infection?


—Children with cystic fibrosis often have recurrent respiratory tract infections. Ciliary dyskinesis is associated with frequent cough, sinusitis, and otitis media.


Is there a history of preterm birth or did the child require mechanical ventilation or prolonged supplemental oxygen after birth?


—Bronchopulmonary dysplasia chronic lung disease of prematurity should be considered.


Are there allergic shiners, Dennie lines, nasal crease, or atopic dermatitis?


—The presence of atopy increases the likelihood of asthma.


Are symptoms exacerbated by feeding?


—Gastroesophageal reflux and tracheoesophageal fistula should be considered. H-type tracheoesophageal fistulas may not be accompanied by esophageal atresia.


Was the mother tested for sexually transmitted diseases during pregnancy?


Chlamydia trachomatis pneumonia may present during the second month of life with nonpurulent conjunctivitis, wheezing, and pneumonia without fever.


Is there a family history of wheezing or asthma?


—A family history of asthma in either or both parents increases the risk of the patient having asthma to 2-3 times above the baseline prevalence.


SUGGESTED READING


1. Bjerg A, Hedman L, Perzanowski MS, et al. Family history of asthma and atopy: in-depth analyses of the impact on asthma and wheeze in 7- to 8-year-old children. Pediatrics 2007;120:741-748.


The following cases represent less common causes of wheezing in childhood.


CASE 1-1


Eight-Month-Old Girl


DUSTIN R. HAFERBECKER


HISTORY OF PRESENT ILLNESS


The patient was an 8-month-old girl who presented to the emergency department for the third consecutive day with parental complaints of wheezing and cough. Two days prior to admission she was examined in the emergency department, diagnosed with bronchiolitis and otitis media and discharged on amoxicillin, nebulized albuterol, and prednisolone. One day prior to admission, she was again evaluated in the emergency department for continued wheezing and cough which improved with nebulized albuterol. A chest radiograph demonstrated hyperinflation and peribronchiolar thickening. There was no cardiomegaly or pleural effusion. On the day of admission, her cough was accompanied by two episodes of perioral cyanosis. She had decreased oral intake and urine output and was febrile to 39.7°C at home.


MEDICAL HISTORY


The girl’s history was remarkable for frequent episodes of wheezing since 5 months of age. She had received nebulized albuterol intermittently, including every 4 hours for the past month, without significant improvement in her wheezing. Her cough was worse at night but did not seem to be worse with feeding or supine positioning. Her birth history was unremarkable and the prenatal ultrasound was reportedly normal.


PHYSICAL EXAMINATION


T 38.3°C; RR 60/min; HR 110 bpm; BP 110/55 mmHg; SpO2 100% in room air


Height 25th percentile; Weight 25th percentile; Head circumference 25th percentile


Initial examination revealed a well-nourished, acyanotic infant in moderate respiratory distress. Physical examination was remarkable for purulent rhinorrhea and buccal mucosal thrush. Moderate intercostal and subcostal retractions were present. There was fair lung aeration with diffuse expiratory wheezing. No murmurs or gallops were heard on cardiac examination and femoral pulses were palpable. No hepatomegaly or splenomegaly was present.


DIAGNOSTIC STUDIES


Laboratory analysis revealed 14 600 white blood cells/mm3 with 38% segmented neutrophils, 53% lymphocytes, and no band forms. The hemoglobin was 11.0 g/dL and there were 580 000 platelets/mm3. Electrolytes, blood urea nitrogen, and creatinine were normal. Polymerase chain reaction performed on nasopharyngeal aspirate was negative for Bordetella pertussis. Antigens of adenovirus, influenza A and B viruses, parainfluenza virus types 1, 2, and 3, and respiratory syncytial virus were not detected by immunofluorescence of nasopharyngeal washings. However, respiratory syncytial virus subsequently grew in viral culture of the nasopharyngeal aspirate. Blood and urine cultures were subsequently negative.


COURSE OF ILLNESS


The patient was diagnosed with bronchiolitis, and her tachypnea and wheezing improved over time. She was treated with nebulized albuterol and oral prednisolone, with unclear benefit. She was discharged after 3 days of hospitalization, receiving albuterol every 4 hours as needed. A radionuclide milk scan was scheduled on an outpatient basis to assess the presence of gastroesophageal reflux and pulmonary aspiration.


Ten days later the patient returned to the emergency room with increased wheezing and recurrence of fever. She had poor oral intake which had not improved significantly since the last admission and was now accompanied by frequent emesis. She was admitted for treatment and further evaluation. Her radionuclide milk scan which had been performed between admissions revealed gastroesophageal reflux without pulmonary aspiration. During her current admission, careful examination of the chest radiograph suggested the diagnosis (Figures 1-1A and B). Magnetic resonance imaging (MRI) of the chest confirmed this diagnosis (Figure 1-1C).



Image


FIGURE 1-1. A. Antero-posterior chest radiograph. B. Lateral chest radiograph. C. Chest MRI.


DISCUSSION CASE 1-1


DIFFERENTIAL DIAGNOSIS


The causes of recurrent or persistent wheezing in infant are diverse. Common causes of recurrent wheezing in infancy include bronchiolitis, reactive airways disease, and gastroesophageal reflux with microaspiration. Less commonly, recurrent wheezing is caused by congenital abnormalities of the lung or respiratory tract (congenital cystic adenomatous malformations, tracheoesophageal fistula), diaphragmatic abnormalities (paralysis of the diaphragm, congenital diaphragmatic hernia), cystic fibrosis, or immunologic defects (congenital absence of thymus, DiGeorge syndrome or other 22q11 deletion syndromes, chronic granulomatous disease, gamma globulin deficiencies). Rarely, anomalies of the major arterial branches of the aorta or pulmonary blood vessels may compress the trachea and bronchi of the infant causing acute or progressive respiratory distress. The features of this case which prompted additional evaluation included recurrent episodes of wheezing, incomplete resolution of wheezing despite prolonged beta-agonist therapy, and episodes of cyanosis.


DIAGNOSIS


The chest radiographs revealed a midline trachea with bilateral indentations in the anteroposterior projection (Figure 1-1A, arrows) and anterior bowing of the trachea on the lateral projection (Figure 1-1B). These findings suggested the diagnosis of double aortic arch. MRI of the chest showed the bifurcation of this double arch as the “horseshoe” structure surrounding the trachea in the center of the image (Figure 1-1C). There were no associated structural defects of the heart. The diagnosis is double aortic arch.


INCIDENCE AND ANATOMY OF VASCULAR RINGS AND SLINGS


Vascular anomalies, commonly referred to “vascular rings and slings,” can cause tracheal or esophageal compression leading to respiratory symptoms or feeding difficulty. The term vascular ring refers to any aortic arch anomaly in which the trachea and esophagus are completely surrounded by vascular structures. The vascular structures do not have to be patent. For example, a ligamentum arteriosum may complete a ring. A vascular or pulmonary sling refers to an anomaly in which vascular structures only partially surround the lower trachea but cause tracheal compression. Vascular rings are seen in less than 1% of congenital cardiac anomalies.


The most commonly occurring rings and slings are depicted in Figure 1-2.



Image


FIGURE 1-2. Anatomy of vascular rings and slings: (A) double aortic arch; (B) right aortic arch with anomalous left subclavian artery and left ligamentum arteriosum; (C) aberrant right subclavian artery; and (D) aberrant left pulmonary artery.


Double aortic arch. This is the most common clinically recognized form of vascular ring and, as the name implies, both right and left aortic arches are present. Left and right aortic arch refer to which bronchus is crossed by the arch, not to which side of the midline the aortic root ascends. The ascending aorta divides anterior to the trachea into left and right arches, which then pass on either side of the trachea. The right arch is usually higher and larger and gives rise to the right common carotid and right subclavian arteries. The right arch travels posteriorly and indents the right side of the trachea and the right and posterior portions of the esophagus, as it passes behind the esophagus to join the left arch at the junction of the left-sided descending aorta. The left arch gives rise to the left common carotid and left subclavian arteries. The left arch is located anteriorly and indents the left side of the trachea and esophagus as it joins the descending aorta. Double aortic arch is rarely associated with congenital heart disease, but when present tetralogy of Fallot is the most common, and transposition of the great arteries is occasionally seen. Surgical division of one of the arches, usually the smaller one, is curative. Respiratory symptoms may persist for months postoperatively because of prolonged deformity of the tracheo-bronchial tree.


Aberrant right subclavian artery. This is also known as left aortic arch with retroesophageal right subclavian artery. It is the most common aortic arch malformation noted on postmortem examination. The incidence of this abnormality in the general population is approximately 0.5%. Aberrant right subclavian artery was found in 0.9% of 3427 consecutive patients undergoing cardiac catheterization at The Children’s Hospital of Philadelphia. It represented 20% of aortic arch anomalies found at catheterization. It is also seen in approximately one-third of Down syndrome patients with congenital heart disease. The left aortic arch has a normal course to the left and anterior to the trachea. However, the right subclavian artery arises as the last branch of the arch and runs posteriorly from the descending thoracic aorta to reach the right arm, passing obliquely up to and right behind the esophagus and indenting it posteriorly. Although most patients with this anomaly are asymptomatic, an older patient may complain of dysphagia. Symptomatic anterior tracheal compression results if there is a common origin of both carotid arteries in conjunction with a retroesophageal aberrant right subclavian artery. Rarely, an anomalous right subclavian artery in association with a left aortic arch, retroesophageal descending aorta, and right ligamentum arteriosum produces a symptomatic vascular ring.


Right aortic arch with anomalous left subclavian artery and left ductus arteriosus or ligamentum arteriosum. The aortic arch passes to the right of the trachea, becomes retroesophageal, and descends on left. The first branch is the left carotid artery, the second is the right carotid artery, the third the right subclavian artery, and the fourth the left subclavian artery, which arises from the descending aorta. The ductus arteriosus originates from a retroesophageal diverticulum of the descending aorta, courses to the left and connects to the pulmonary artery. Patients are usually asymptomatic. However, some patients present with wheezing or stridor because of tracheal compression and require surgical division of the ligamentum arteriosum. Older children with dysphagia may require relief of esophageal compression by actual division of the aortic arch. The retroesophageal portion is mobilized and reanastomosis of ascending and descending portions of the aorta is completed using a graft.


Aberrant left pulmonary artery (pulmonary sling). A normal pulmonary artery is absent, and the left lung is supplied by an anomalous left pulmonary artery arising from the distal right pulmonary artery. The vessel courses to the right of the trachea and then passes between the trachea and esophagus, causing compression of the right main stem bronchus, trachea, and esophagus. The resulting compression of the right main stem bronchus and trachea leads to airway obstruction, primarily affecting the right lung. Two-thirds of affected infants present in the first month of life with wheezing, stridor, or apnea. Dysphagia is rare. There may be associated collapse or hyper-inflation of the right lung. Aberrant left pulmonary artery is frequently associated with complete cartilaginous rings in the distal trachea, resulting in tracheal stenosis. It usually appears as an isolated abnormality but can be associated with other congenital cardiac defects, particularly tetralogy of Fallot. Surgical repair involves division of the left pulmonary artery from the right and reanastomosis in front of the trachea. Bronchoscopy is performed at the time of surgical repair because of the frequent association of complete cartilaginous rings causing tracheal stenosis.


CLINICAL PRESENTATION OF VASCULAR RINGS AND SLINGS


Most infants present with symptoms in early infancy. Superimposed viral infection with edema of the trachea or bronchi may account for or contribute to the respiratory symptoms. Asymptomatic infants, particularly those with aberrant right subclavian artery, are sometimes diagnosed incidentally on chest radiograph during a viral respiratory illness.


The symptoms of a vascular ring or sling are due to tracheal compression and, to a lesser degree, to esophageal compression. Symptoms of tracheal compression include wheezing, stridor, and apnea. Some infants hyperextend their necks to reduce tracheal compression. Symptoms related to esophageal compression include emesis, choking, and nonspecific feeding difficulties in infants, and dysphagia in older children. Less severe obstructions may present with recurrent respiratory infections as a result of aspiration or inadequate clearing of respiratory secretions.


DIAGNOSTIC APPROACH


Clinicians should have a high index of suspicion for a vascular anomaly in the evaluation of an infant with recurrent wheezing. Chest radiograph and barium esophagogram should be considered in the initial evaluation.


Chest radiograph. The diagnosis of a vascular ring may be suspected prior to barium esophagogram. Chest radiograph should be examined to assess laterality of the aortic arch and for evidence of tracheal or bronchial compression. The following features on chest radiograph are suggestive of a vascular anomaly and require additional evaluation: (1) A midline trachea in which there is no rotation of the patient or a sharp indentation on the right side of the trachea above the carina suggests a right aortic arch. The normal infant’s trachea is slightly displaced to the right by the normal left arch. (2) Lateral displacement of the right mediastinal pleural line indicates a right descending aorta. (3) Anterior bowing of the trachea rather than a normal posterior convexity on the lateral view indicates compression (Figure 1-1B). Generalized or focal areas of hyperinflation because of tracheal or bronchial compression can be mistakenly diagnosed as a foreign body aspiration.


Barium esophagogram. Patients with swallowing difficulties should undergo a barium swallow as part of the initial evaluation. Abnormal compression of the middle part of the esophagus posteriorly (vascular ring) or anteriorly (pulmonary sling) is typically evident.


Magnetic resonance angiography (MRA) and computed tomography angiography (CTA). Both MRA and CTA have been shown to provide excellent anatomic details and are helpful in planning reconstructive procedures.


Angiogram and transthoracic echocardiogram. In the absence of any other cardiac defect, catheter-based angiography has essentially become obsolete because of advances in three-dimensional renderings of MRA and CTA data. Transthoracic echocardiography is important to detect associated congenital cardiac defects but is less reliable at delineating vascular and tracheal anatomy.


Bronchoscopy. This enables direct visualization of compression on the trachea and is indicated when tracheal stenosis is present or suspected.


TREATMENT


Surgical management is necessary to relieve symptomatic obstruction of trachea and esophagus. Surgery should also be considered when the infant has frequent respiratory infections or poor weight gain. The infant with severe preoperative respiratory symptoms is likely to have postoperative tracheomalacia from prolonged compression by the vascular ring. However, feeding difficulties resolve rapidly.


SUGGESTED READINGS


1. Dillman JR, Attili AK, Agarwal PP, et al. Common and uncommon vascular rings and slings: a multi-modality review. Pediatr Radiol. 2011;41:1440-1454.


2. Berdon WE, Baker DH. Vascular anomalies and the infant lung: rings, slings, and other things. Semin Roentgen. 1972;7:39-63.


3. Edwards JE. Malformations of the aortic arch system manifested as “vascular rings.” Lab Invest. 1953;2:56-75.


4. Goldstein WB. Aberrant right subclavian artery in mongolism. Am J Roentgenol Radium Ther Nucl Med 1965;95:131-134.


5. Hawker RE, Celermajer JM, Cartmill TB, Bowdler JD. Double aortic arch and complex cardiac malformations. Br Heart J. 1972;34:1311-1313.


6. Moes CAF, Freedom RM. Rare types of aortic arch anomalies. Pediatr Cardiol. 1993;14:93-101.


7. Weinberg PM. Aortic arch anomalies. In: Emmanouilides GC, Riemenschneider TA, Allen HD, Gutgesell HP, eds. Moss and Adams Heart Disease in Infants, Children, and Adolescents, Including the Fetus and Young Adult. 5th ed. Baltimore: Williams & Wilkins; 1995:810-837.


CASE 1-2


Three-Year-Old Boy


DUSTIN R. HAFERBECKER


HISTORY OF PRESENT ILLNESS


A 3-year-old boy was referred to the emergency department for evaluation of wheezing, cough, and increased work of breathing. He had been well until 3 days prior to admission, when he developed rhinorrhea and cough without fever. Nebulized albuterol was prescribed for wheezing and retractions, with little improvement. On the day of admission, the child’s respiratory distress had continued and his cough had worsened and was accompanied by mild sternal discomfort exacerbated by coughing. He had received nebulized albuterol every 4 hours during the day of admission without significant relief. There was no vomiting or diarrhea. The onset of wheezing was not accompanied by an episode of choking or gagging. There was no history of trauma.


MEDICAL HISTORY


The boy’s medical history was unremarkable. There were no previous episodes of wheezing. He was born at 39 weeks gestational age without perinatal complications. There was no family history of atopic dermatitis or asthma.


PHYSICAL EXAMINATION


T 37.7°C; RR 52/min; HR 130 bpm; BP 108/70 mmHg; SpO2 95% in room air


Weight 50th percentile


Physical examination revealed a fair-haired Caucasian boy in mild respiratory distress. On examination, there was no conjunctival injection or chemosis. Clear rhinorrhea was present. He had mild intercostal and subcostal retractions. His lung examination revealed dullness to percussion, diminished breath sounds, and prominent wheezing at the left base. There was good aeration without wheezing, rales, or rhonchi in the remainder of the left lung and throughout the right side. An I/VI vibratory systolic ejection murmur was present at the left sternal border. His abdomen was thin and soft with active bowel sounds and no organomegaly or palpable mass. The remainder of the physical examination was normal.


DIAGNOSTIC STUDIES


Laboratory analysis revealed 15 100 white blood cells/mm3 with 0% band forms, 52% segmented neutrophils, 33% lymphocytes, and 5% eosinophils. Hemoglobin, platelet count, electrolytes, blood urea nitrogen, and creatinine were normal.


COURSE OF ILLNESS


The patient’s lung examination did not change with the administration of nebulized albuterol. A chest radiograph revealed the diagnosis as indicated in Figure 1-3.



Image


FIGURE 1-3. Chest radiograph. A. Antero-posterior view. B. Lateral view.


DISCUSSION CASE 1-2


DIFFERENTIAL DIAGNOSIS


The most likely cause of a first episode of wheezing in a 3-year-old boy, particularly in the context of an upper respiratory infection, is asthma. Foreign body aspiration should also be strongly suspected in this age group, especially if there are asymmetries on lung examination. Less common causes in this age group include anaphylaxis, which is typically associated with urticaria or other features of a systemic allergic response, and airway compression due to mediastinal tumors, lymph nodes, or other structures. In the immunocompromised host, Pneumocystis jiroveci (formerly P. carinii) pneumonia often presents with tachypnea, wheezing, and respiratory distress in the absence of fever. Children with cystic fibrosis usually have poor weight gain, pancreatic insufficiency, and recurrent respiratory symptoms. The characteristics of this case that prompted additional evaluation included hypoxemia, progressive respiratory distress that was unresponsive to beta-agonist therapy, and the presence of focal wheezing evident on lung examination.


DIAGNOSIS


The chest radiograph (Figure 1-3) revealed a heterogeneous opacity overlying the lower half of the left lung consistent with the appearance of both small and large bowel in the thorax. The mediastinal structures are displaced rightward. The diagnosis is postero-lateral congenital diaphragmatic (Bochdalek) hernia with delayed presentation.


INCIDENCE AND EPIDEMIOLOGY


Congenital diaphragmatic hernia (CDH) is a simple anatomic defect in which a hole in the diaphragm allows abdominal viscera to herniate into the thorax. CDH defects are usually left-sided (80%). The incidence of CDH is estimated to be 1 per 2000 to 5000 births. While most cases of CDH are diagnosed prenatally or during the neonatal period, approximately 10%-20% have delayed presentation (age >1 month). They are thought to occur most often as a sporadic developmental anomaly, although familial cases have been reported. The recurrence risk in a first-degree relative is approximately 2%. Approximately 40% of liveborn patients who have CDH have one or more associated anomalies including cardiac (60%), genitourinary (23%), gastrointestinal (17%), central nervous system (14%), and chromosomal (10%) (Table 1-3). Infants with isolated CDH are more likely to be premature, macrosomic, and male.



TABLE 1-3. The prevalence of associated anomalies detected in 40% of patients with congenital diaphragmatic hernia.


Image


Population-based studies of CDH among live-born, stillborn, and spontaneously aborted fetuses suggest that approximately 30% of fetuses who have CDH will die before birth, usually from chromosomal or lethal nonpulmonary malformations. Among fetuses with prenatally diagnosed CDH and without major associated anomalies, early term delivery (i.e., 37 weeks compared with 39-41 weeks gestational age) may confer a survival advantage. In CDH, the location of the defect may also affect postnatal survival and the development of chronic lung disease. In one study, more neonates with left-sided CDH died of severe pulmonary hypertension despite extracorporeal membrane oxygenation. Fewer neonates with right-sided CDH died, yet higher degrees of pulmonary hypoplasia and oxygen requirement were observed despite extracorporeal membrane oxygenation.


Congenital diaphragmatic hernias may vary in size and occur in various portions of the diaphragm. Types of CDH include postero-lateral (Bochdalek) (59.5%), antero-medial (Morgagni) (2.6%), hiatal (23.3%), and eventration (14.6%). Postero-lateral diaphragmatic hernias result from an absence or defective fusion of the septum transversum dorsally and pleuroperitoneal membrane postero-laterally. There appear to be two groups of patients with delayed presentations of postero-lateral CDH. In the first group, the defect is long-standing, but the viscera are confined by a hernia sac or obturated by a solid organ. Presentation occurs when the sac ruptures or the intraabdominal pressure is raised, causing the viscera to herniate. A previously normal chest radiograph is supportive. The second group also has a congenital defect but only present when a complication of the herniated contents such as volvulus, strangulation, or acute or recurrent respiratory distress develops.


CLINICAL PRESENTATION


Many patients with CDH are diagnosed antena-tally by ultrasound. In such instances, other congenital anomalies, particularly those affecting the cardiovascular and central nervous systems, should be sought. The presentation of CDH in the neonatal period is determined primarily by the severity of the pulmonary hypoplasia and pulmonary hypertension. The most severely affected infants show obvious respiratory signs within the first 24 hours of life. Classically, these infants are born with a scaphoid abdomen and develop progressive respiratory distress as swallowed air causes intestinal distension followed by worsening lung compression and mediastinal shift. These infants may have cyanosis, increased work of breathing, and respiratory failure.


In contrast, the presentation of diaphragmatic hernia outside the neonatal period is extremely varied, and may be associated with misleading clinical and radiologic assessments. Children who have CDH with delayed presentation may have recurrent respiratory distress, chronic pulmonary infection, or acute gastrointestinal symptoms caused by gastric volvulus or intestinal obstruction.


DIAGNOSTIC APPROACH


Prenatal ultrasound. CDH may be diagnosed by ultrasound during routine obstetric screening or during investigation of polyhydramnios, which may complicate up to 80% of pregnancies in which CDH occurs. The accuracy of prenatal diagnosis varies, depending on the site of the lesion and the presence of corroborating criteria, such as mediastinal shift and abnormal fetal abdominal anatomy. The diagnosis is suggested strongly by the presence of a fluid-filled stomach or intestine at the level of the four-chamber view of the heart.


Fetal MRI. In cases where CDH is expected based on ultrasound but remains unclear, fetal MRI has the potential to assist in the diagnosis. The additional information provided by MRI may also be helpful in counseling the family regarding potential value of prenatal and postnatal interventions.


Associated studies. Once the diagnosis of CDH in a neonate has been confirmed, a careful search for associated anomalies should be performed. Additional studies to consider include renal and cranial ultrasonography, echocardiography, and karyotyping.


Chest radiograph. The diagnosis is confirmed by a chest radiograph that demonstrates loops of intestine within the chest. The location of the gastric bubble should also be noted, and its position can be confirmed by placement of a nasogastric tube. Occasionally, a large multicystic lung lesion such as congenital cystic adenomatoid malformation will have the appearance of a CDH on plain radiography. In these instances, ultrasonographic visualization of an intact diaphragm or computed tomographic scan of the chest may be necessary. In an older child, the radiographic appearance of CDH may be misinterpreted pneumothorax, pneumatocele, or lobar consolidation.


Upper gastrointestinal barium series. Confirmative barium studies represent an unnecessary delay in appropriate therapy for the neonate. However, in the older child they serve to confirm the diagnosis. Additionally, up to 30% of children with delayed presentation of CDH have associated abnormalities of bowel fixation or rotation requiring repair.


TREATMENT


Prenatal care. Antenatal diagnosis of CDH has allowed optimal immediate care of affected infants. Birth at a tertiary care center that has pediatric surgery and neonatology services as well as advanced strategies for managing respiratory failure, including extracorporeal membrane oxygenation (ECMO), usually is most appropriate. A spontaneous vaginal delivery should be anticipated unless obstetric issues dictate otherwise.


Fetal therapy. The role of in utero surgery for CDH remains controversial. Fetal intervention is currently focused on temporary occlusion of the fetal trachea for those fetuses who have CDH and liver herniation above the diaphragm in an attempt to correct the severe pulmonary hypoplasia often associated with CDH. Normally, fetal lungs produce a continuous flow of fluid that exits the trachea into the amniotic space. In the presence of tracheal obstruction, the lungs grow, and there is gradual reduction of herniated viscera back into the abdomen. Following a period of intrauterine tracheal occlusion sufficient to cause a reversal of pulmonary hypoplasia, the fetus is delivered and maintained on placental support until the tracheal obstruction is relieved and an adequate neonatal airway is established. Other forms of antenatal therapy include the development of pharmacologic strategies that target pulmonary growth and development.


Delivery room and intensive care. Immediate resuscitation includes prompt endotracheal intubation, avoidance of bag-mask ventilation, placement of a nasogastric tube to provide intestinal decompression, and ongoing care in an intensive care nursery by individuals experienced in the management of the newborn who has CDH.


Surgical repair in the neonate. Historically, neonates who had CDH were rushed to the operating room under the mistaken belief that decompression of the lungs by reduction of the abdominal viscera offered the greatest chance of survival. This disorder is no longer thought to require immediate surgery because the primary problem after birth is not herniation of abdominal viscera into the chest but severe pulmonary hypoplasia and associated pulmonary hypertension. Average time to surgery now ranges from 3 to 15 days after birth. New treatments including ECMO and permissive hypercapnia with gentle ventilation to minimize barotrauma have led to incremental increases in survival rates which now range from 78% to 94%. Other treatments such as partial liquid ventilation, inhaled nitric oxide, surfactant-replacement therapy, and maternal corticosteroid therapy prior to birth require additional study in patients with CDH.


Surgical repair in the child with delayed presentation. The timing of repair in patients who present with CDH beyond the neonatal period typically occurs within days of presentation, or earlier if symptoms are acute. The prognosis in late-presenting CDH is good. It does not depend on lung hypoplasia as in neonatal CDH, but relates to accurate diagnosis of the condition and immediate operative correction in symptomatic cases. Complications of delayed repair in the symptomatic patient include incarceration or strangulation of herniated bowel and cardio-respiratory arrest due to mediastinal compression by the herniated viscera.


SUGGESTED READINGS


1. Deprest JA, Nicolaides K, Gratacos E. Fetal surgery for congenital diaphragmatic hernia is back from never gone. Fetal Diagn Ther. 2011;29:6-17.


2. Fotter R, Schimpl G, Sorantin E, Fritz K, Landler U. Delayed presentation of congenital diaphragmatic hernia. Pediatr Radiol. 1992;22:187-191.


3. Berman L, Stringer D, Ein SH, Shandling B. The late-presenting pediatric Bochdalek hernia: a 20-year review. J Pediatr Surg. 1988;23:735-739.


4. Dott MM, Wong LY, Rasmussen SA. Population-based study of congenital diaphragmatic hernia: risk factors and survival in Metropolitan Atlanta, 1968-1999. Birth Defects Res A Clin Mol Teratol. 2003;67:261-267.


5. Mayer S, Klaritsch P, Petersen S, et al. The correlation between lung volume and liver herniation measurements by fetal MRI in isolated congenital diaphragmatic herni: a systematic review and meta-analysis of observation studies. Prenatal Diag. 2011;31:1086-1096.


6. Schaible T, Kohl T, Reinshagen K, et al. Right- versus left-sided congenital diaphragmatic hernia: postnatal outcome at a specialized tertiary care center. Pediatr Crit Care Med. 2012;13:66-71.


7. Skarsgard ED, Harrison MR. Congenital diaphragmatic hernia: the surgeon’s perspective. Pediatr Rev. 1999;20:e71-e78.


8. Stevens TP, van Wijngaarden E, Ackerman KG, Lally PA, Lally KP for the Congenital Diaphragmatic Hernia Study Group. Timing of delivery and survival rates for infants with prenatal diagnoses of congenital diaphragmatic hernia. Pediatrics. 2009;123:494-502.


9. Stolar CJH, Dillon PW. Congenital diaphragmatic hernia and eventration. In: O’Neill JA Jr., Rowe MI, Grosfeld JL, Fonkalsrud EW, Coran AG, eds. Pediatric Surgery. 5th ed. St. Louis: Mosby; 1998:819-837.


10. Thibeault DW, Sigalet DL. Congenital diaphragmatic hernia from the womb to childhood. Curr Probl Pediatr. 1998;28:5-25.


CASE 1-3


Five-Week-Old Boy


DUSTIN R. HAFERBECKER


HISTORY OF PRESENT ILLNESS


A 5-week-old boy presented to the emergency department with a one-day history of fever and “wheezing.” His visit to the hospital was prompted by a rectal temperature of 38.6°C. His respiratory difficulty seemed worse with feeding. There had been no emesis, diarrhea, rhinorrhea, cough, or cyanosis. He had been drinking approximately 4 ounces of a cow milk-based formula every 3 hours. His only ill contact was his mother who had cough and rhinorrhea for one week.


MEDICAL HISTORY


The boy was born by spontaneous vaginal delivery at 39 weeks gestation. His birth weight was 3900 g. The pregnancy, labor, and delivery were uncomplicated. Prenatal ultrasound revealed polyhydramnios but was otherwise normal. The mother’s prenatal laboratory studies included a negative group B Streptococcus screen. Testing for antibodies to human immunodeficiency virus had not been performed. The infant had not previously been hospitalized.


PHYSICAL EXAMINATION


T 38.5°C; HR 180 bpm; RR 70/min; BP 62/40 mmHg; SpO2 96% in room air


Length 25th percentile; Weight 50th percentile


The infant was ill appearing with moderate respiratory distress. His anterior fontanelle was open and flat. There was no conjunctival injection or discharge. There was intermittent grunting and nasal flaring. Moderate intercostal and subcostal retractions were present. Breath sounds were diminished throughout the left chest. The right lung was clear to auscultation. There was no wheezing. The heart sounds were normal. The liver was palpable 1 cm below the right costal margin. The spleen was not palpable. The moro reflex, grasp, tone, and reflexes were normal. There were no rashes or petechiae.


DIAGNOSTIC STUDIES


Arterial blood gas revealed the following: pH, 7.40; PaCO2, 40 mmHg; PaO2, 214 mmHg; and bicarbonate, 26 mEq/L. Complete blood count demonstrated 37 900 white blood cells/mm3 (3% band forms; 67% segmented neutrophils; and 30% lymphocytes). The platelet count was 520 000/mm3 and hemoglobin was 9.4 g/dL. Serum electrolytes, blood urea nitrogen, and creatinine were normal. There were no white blood cells, protein, or nitrites on urinalysis. A blood culture was obtained. Lumbar puncture was not performed because of the patient’s respiratory distress. Chest radiograph demonstrated left lower lobe consolidation with an associated pleural effusion causing rightward shift of the mediastinal structures (Figure 1-4).



Image


FIGURE 1-4. Chest radiograph.

Only gold members can continue reading. Log In or Register to continue

Mar 23, 2021 | Posted by in PEDIATRICS | Comments Off on Wheezing
Premium Wordpress Themes by UFO Themes