Post on 03-Apr-2018
transcript
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