Masqueraders of Asthma: Wheezing in Infants &Children

Howard B. Panitch, M.D.

Division of Pulmonary Medicine

The Children’s Hospital of Philadelphia

All that wheezes is not asthma….(Chevalier Jackson, MD)

…but often it is!

How is This Child Different?

• History• Physical examination

• Physiological differences• Pulmonary function studies• Imaging• Endoscopy

Historical Clues

• Perinatal respiratory problems• Prematurity? BPD? Airway intubation?

• Timing of symptoms• At rest / with exercise or crying• During feedings vs after feedings

• Recurrence vs Persistence• Dynamic vs fixed process

• Response to prior therapies

+

+

ExpirationInspiration

Physical Examination

Noise Reflects the Anatomic Site of Obstruction

Rc 1.8 10Rp 0.2 10Rt 2.0 20

Rc 1.8 10

Rp 0.4 20

Rt 2.2 30

Rc

Rp

Rc

Rp

Adult Infantcm H2O/L/sec

Human Tracheal Compliance

Croteau J and Cook C. J Appl Physiol 16:170; 1961

1-5 days (5)

1-7 months (3)4-11 yrs. (5)

16 yrs (1)50-58 yrs (5)69 & 94 yrs

150

-40 -20 20 40 60 cm H2O

120

90

60

30

-60

-30

-60

-90

∆VV

X 100

• Pleural pressure• Intraluminal pressure

• Intrinsic rigidity (compliance) of airway wall

Transmuralpressure

Factors Affecting Collapse of Large Airways

Effect of Collapsing Pressures on Tracheal Cross-Sectional Area

Collapsing Pressure (cm H2O)

0 20 30 40

From: Panitch HB et al. Pediatr Res 43:832; 1998

Effect of Peripheral Obstruction

Heterophonous Wheezing

• Acute• Bronchiolitis• Asthma• Vocal cord dysfunction

• Persistent / Recurrent• Asthma• Cystic Fibrosis• Gastroesophageal reflux• Local or systemic immune deficiency

Asthma: Key Diagnostic Elements-The R’s•Recurrence

• vs persistent•Response to bronchodilators

• Clinical, objective measurements•Reaction to “triggers”

• viral infections, allergens, smoke

*absence of unassociated findings (excludeother diagnoses)

Heterophonous Wheezing: Danger Signs

• Poor growth• Intestinal malabsorption• Recurrent infections

• Recurrent sinopulmonary infections• Extrapulmonary infections

• Digital clubbing• Neonatal distress

GERD and Asthma

•Both diseases occur frequently• 5-12% children with asthma• 8-13% infants and children with GERD

•Nocturnal or post-prandial symptoms• 44% wheezing infants with abnormal pH probeshad no sxs1

•Not all studies demonstrate improvementwith GERD Rx2

1Sheikh S et al. Pediatr Pulmonol 28:181; 19992Writing Committee for ALA Asthma Clinical Research Centers. JAMA 307:373; 2012

Asthma GER

•Vagal reflexes•Neurogenicinflammation

• Substance P• Neurokinin A

•Microaspiration•Heightenedbronchialreactivity

Scarupa MD et al. Pediatr Drugs 7:177; 2005

Homophonous Wheezing

• Acute• Foreign body aspiration

• Persistent / Recurrent• Non-structural

• Gastroesophageal reflux• Retained foreign body• Chronic bacterial bronchitis

Foreign Body AspirationClinical Findings

• Unequal breath sounds• Localized wheezes• History of choking episode absent in 30%

Foreign Body AspirationRadiographic Findings• Localized hyperinflation• Localized atelectasis• Differential density

• Inspiratory / Expiratory films• Decubitus views

*A normal radiograph cannot RULE OUT a Retained Foreign Body

• 10 month old with 3 month history of wheezing• Hospitalized at 7 months for wheezing, treated with

bronchodilators and steroids• Improved, but wheezing never resolved• Homophonous wheezing

2 yo with wheezing

Foreign Body AspirationManagement

• If HIGHLY SUSPECTED• Open tube (rigid) bronchoscopy

• If POSSIBLE but NOT HIGHLY SUSPECTED• May consider flexible bronchoscopy

Chronic Bacterial Bronchitis (Protracted Bacterial Bronchitis)•Longstandiung wheeze with “wet” cough•Protracted infection of conducting airways

• Non-typable Haemophilus influenzae• Moraxella catarrhalis• Streptococcus pneumoniae

•Biofilms, impaired mucociliary clearance•No identifiable immunodeficiencies•Definitive dx: bronchoscopy and BAL

Craven V et al. Arch Dis Child 98:72; 2013

Homophonous Wheezing

• Structural• Tracheomalacia / bronchomalacia• Vascular compression / Rings• Tracheal stenosis / webs• External compression• Intraluminal masses

TracheomalaciaClinical Considerations

• Often “happy wheezers”• May worsen obstruction after bronchodilator

therapy• Can often improve with bronchconstrictor

therapy• Bethanechol• Ipratropium

Tracheomalacia

• Congenital• Tracheoesophageal fistula• Vascular compression• Isolated

• Acquired• Mechanical ventilation• Severe peripheral obstruction

Hysinger EB and Panitch HB. Paediatr Respir Rev. 2015 Mar 17. doi: 10.1016/j.prrv.2015.03.002.

Normal Trachea

Intrathoracic Tracheomalacia

Wheezing in Congenital Heart Disease

• Mucosal edema with airway narrowing• Enlarged (hypertensive) pulmonary arteries• Vascular rings

Anomalous Innominate Artery

Double Aortic Arch

Quarello E et al. Prenat Diagn 27:1180; 2007

Complete Tracheal Rings

Choosing a path…

• Exclude “red flags” or specific diagnoses• Presence of “3R”s

Ask: How is this not like asthma?• Consider trial of anti-asthma therapy• Need to objectively monitor response

Evaluation of WheezingMain Studies

• Chest radiograph – 2 views• Chest CT(A) (insp and exp)• ?MRI/MRA• Pulmonary function testing

• Clinical response to agonist• Bronchoscopy +/- BAL

10 year girl“Asthma” x 3 yrsEx preemieBiphasic wheeze? Response to Rx

Dx.: subglotticStenosis

Rx: surgical

Evaluation of WheezingAdjunctive Studies

• Sweat test• Immunological evaluation• Airway fluoroscopy• pH probe / gastric scintigraphy

Summary

• Timing and quality of the sound help distinguish site(s) of obstruction

• Response to prior therapies can direct subsequent evaluation

• Establishing the site of obstruction leads the diagnostic evaluation