wheeze in children
TRANSCRIPT
Wheezing in children
Dr Divya Nair
Department of Pediatrics,
Mahavir Hospital & Research Centre,
Hyderabad.
Introduction Wheeze is a continuous & musical sound that
originates from oscillations in narrowed
airways
Mostly heard in expiration due to critical
airway obstruction
Sign of lower (intra-thoracic) airway
obstruction
If there is widespread narrowing of airways
leading to various levels of obstruction to
airflow (eg. asthma), polyphonic wheeze is
heard i.e. sounds of various pitches
Monophonic wheeze (single pitch) is produced
in larger airways during expiration eg. distal
tracheomalacia, bronchomalacia
Infants & children are prone to wheeze due to different set of lung mechanics ( as compared to older children & adults)
Obstruction to airflow airway caliber
compliance of lung
1) Resistance = 1/ ( radius of tube)4
In children < 5 years, small caliber peripheral
airways can contribute upto 50% of airway
resistance
Marginal additional narrowing can cause further
flow limitation & subsequent wheeze
2) Compliant chest walls, especially in newborns,
leads to intra-thoracic airway collapse due to
inward pressure produced in expiration
3) Differences in tracheal cartilage composition &
airway muscle tone causes further increase in
airway compliance
All these mechanisms combine to make the
Infant more susceptible to airway collapse
Increased resistance
Subsequent wheeze
Many of these are outgrown in the 1st year
of life itself
4) Immunologic & molecular influences:
Infants have increased levels of lymphocytes &
neutrophils in BAL fluid
Variety of inflammatory mediators have been
implicated eg. Histamine, leukotrienes,
interleukins, etc
Fetal & early post-natal “programming” affects the
structure & function of fetal lung by factors
including fetal nutrition, fetal & neonatal exposure
to maternal smoking
DD’s of wheezing: 1) INFECTION:
Viral : RSV (Bronchiolitis)
Human metapneumovirus
Influenza, Parainfluenza
Adenovirus
Rhinovirus
Others: TB
Chlamydia trachomatis
Histoplasmosis
2) ASTHMA:
i) Transient wheezer - risk factor is primarily
diminished lung size
ii) Persistent wheezers – initial risk factors being
passive smoke exposure, maternal asthma
history, persistent rhinitis, eczema <1yr age,
increased IgE in 1st yr of life
At an increased risk of developing clinical
asthma
iii) Late onset wheezer
3) Anatomic abnormalities:
a) Central airway abnormalities:
- Malacia of larynx, trachea, bronchi
- Tracheoesophageal fistula ( H type)
- Laryngeal cleft (leading to aspiration)
b) Extrinsic airway anomalies (leading to com-
pression):
- Vascular ring/ sling
- Mediastinal LN’pathy (infection/ tumor)
- Esophageal foreign body
c) Intrinsic airway anomalies:
- Airway hemangioma
- Cystic adenomatoid malformation
- Bronchial/ lung cyst
- Congenital lobar emphysema
- Aberrant tracheal bronchus
- Sequestration
- CHD with L R shunt ( pulmonary edema)
- Foreign body
4) Immunodeficiency states:
- IgA deficiency
- B cell defiency
- AIDS
- Bronchiectasis
5) Mucociliary clearance disorders:
- Cystic fibrosis
- Primary ciliary dyskinesias
- Bronchiectasis
6) Bronchopulmonary Dysplasia
7) Aspiration Syndromes
- GERD
- Pharyngeal/ swallow dysfunction
8) Interstitial lung disease
9) Heart Failure
10) Anaphylaxis
11) Inhalation Injury – Burns
12) WALRTI, Wheeze a/w URTI
13) Drugs: Ibuprofen, Aspirin, Rifampicin, Erythromycin
Etiology: I) ACUTE BRONCHIOLITIS:
- It is acute inflammation of the airways
- predominantly a viral disease
- cause: RSV ( > 50%) , parainfluenza,
adenovirus, mycoplasma, human metapneumovirus
- more common in males, not breast fed, live in
crowded conditions
- older family members are source of infection
- LRTI manifestations are minimal in older patients in
whom bronchial edema is better tolerated
- RSV infection leads to a complex immune response
i) Eosinophils degranulate release Eosinophilic
Cationic Protein cytotoxic to airway epithelium
ii) IgE antibody release may be related to wheezing
iii) Other mediators: Chemokines (IL-8, Macrophage
Inflammatory Protein); Leukotrienes , IF gamma
- Characterized by bronchiolar obstruction with
edema, mucus & cellular debris
- Resistance in small airway is increased more in exhalation than
inspiration respiratory obstruction early air trapping &
overinflation complete obstruction atelectasis
- Hypoxemia occurs early in the course due to
VQ mismatch
- Hypercapnia develops due to severe
obstructive disease and respiratory fatigue
II) ALLERGY & ASTHMA:
- Important cause of wheezing
- Characterized by:
airway inflammation,
bronchial hyper-reactivity,
reversibility of obstruction
- 3 identified patterns:
a) Transient early wheezer: 20% of population
Before the age of 3yrs had wheezing at least
once, with LRTI but never wheezed again
b) Persistent wheezer: 14% of population
Before 3yrs age had wheezing episodes
still wheezing at 6yrs age
c) Late onset wheezer: 15% of population
No wheezing by 3yrs but wheezing by
6yrs
- The remaining 50% of children had never
wheezed by 6yrs of age
III) CHRONIC INFECTIONS:
- Should be considered in infants who seem
to fall out of range of a normal clinical
course
- Cystic fibrosis is a common cause
- Persistent respiratory symptoms, digital
clubbing, malabsorption, FTT, electrolyte
abnormalities, resistance to bronchodilator
therapy
IV) CONGENITAL MALFORMATIONS:
- Causes wheezing in early infancy
- Findings can be diffuse or focal
- Can be from an ext compression/ intrinsic abn
- External vascular compression: vascular ring/
sling compressing trachea/ esophagus
- CVS causes: massive cardiomegaly, LA
enlargement, dilated pulmonary arteries
- Pulmonary edema d/t CHF lymphatic &
bronchial vessel engorgement obstruction &
edema of bronchioles Wheeze
V) FOREIGN BODY ASPIRATION:
- Can cause acute/ chronic wheezing
- Common between 2mths- 4 yrs of age
- Infants may present with atypical histories or
misleading radiological/ clinical findings
- D/d: asthma, other obstructive disorders
- Esophageal FB can transmit pressure to
membranous trachea compromises the
airway lumen
VI) GASTROESOPHAGEAL REFLUX:
- can cause direct aspiration into tracheo-
bronchial tree
- may trigger a vagal/ neural reflex
increased airway resistance
airway reactivity
VII) TRAUMA & TUMORS:
- rare causes of wheezing in children
- trauma of any type to TB tree (aspiration/ burns/ scalds)
inflammation of the airways subsequent wheeze
- SOL (lung/ extrinsic) compression
obstruction to airway
Clinical Manifestations HISTORY & PHYSICAL EXAMINATION
- ODP & associated factors of wheezing:
- Birth history: weeks of gestation, NICU admission,
h/o intubation/ O2 requirement, maternal
complications eg. Infn- HSV, HIV; prenatal smoke
exposure
- Past medical history: co-morbid conditions eg.
syndromes or association
- Social history:
Environmental history of smokers at home,
number of siblings, occupation of inhabitants at
home, pets, TB exposure
- Family history:
of CF, immuno-deficeincy, asthma in 1st degree
relatives OR
any other recurrent respiratory conditions should
be obtained
RISKS OF FAMILY HISTORY OF ATOPY
No family history : 16%
Single parent atopy : 22%Maternal Atopy : 32 %
Both parents atopic : 50%
(Aberdeen Study 1994)
Pertinent medical history in wheezing infant:
Did the onset of symptoms begin at birth or thereafter?
Is the infant a noisy breather & when is it most prominent?
Is there a history of cough apart from wheezing?
Was there an earlier LRTI?
Have there been any emergency department visits, hospitalizations, or ICU admission for RD?
Is there a history of eczema?
How is the infant growing & developing?
Is there associated failure to thrive?
Is there failure to thrive without feeding difficulties?
Are there s/o intestinal malabsorption including frequent , greasy, or oily stools?
Is there a maternal history of genital HSV infection?
What was the gestational age at delivery?
Was the patient intubated as neonate?
Does the infant bottle feed in the bed or crib, especially in propped position?
Are there any feeding difficulties including choking, gagging, arching, or vomiting with feeds?
Any new food exposure?
Is there a toddler in the home or lapse in supervision in which foreign body aspiration could have happened?
Change in caregivers or chance or non accidental trauma?
Physical examination:
- Vitals especially RR, SPO2
- Growth charts for s/o FTT
- Upper airway s/o atopy: boggy turbinates ,
posterior oropharynx cobblestoning
- Evaluate skin for eczema, hemangioma
- Midline lesions may be associated with
intrathoracic lesions
- Clubbing
- S/O RD- Tachypnea, nasal flaring, tracheal
tugging, SCR/ICR, excessive use of accessory
muscles
- Prolonged expiratory time, expiratory whistling
sounds
- Auscultation: aeration to be noted, expiratory
wheeze, lack of audible wheeze due to complete
airway obstruction
- Trial of bronchodilators to evaluate change of
wheezing
- Stridor +/-.
Air Trapping Hyperinflated chest
Barrel shaped
Loss of cardiac dullness
Liver pushed down
Hoover sign
Normal diagphragm movement
Hyperinflation = diaphragm flattened
Diaphragm contraction = paradoxical inward
movement of lower interrcostal area during
inspiration
In Acute Bronchiolitis:
- h/o exposure to older contact with URTI
infant 1st develops mild URTI with sneezing &
rhinorrhea may be associated with
decreased appetite & fever gradually RD
ensues with paroxysmal wheezy cough,
dyspnea, irritability
- Apnea may be more prominent than
wheezing early in the course of disease esp
with very young infants ( < 2 mths ) or former
premature infants
- Degree of tachypnea doesn’t always correlate
with degree of hypoxemia/ hypercarbia
- Fine crackles/ overt wheezes present
- Hyperinflation of lungs palpation of liver &
spleen
Diagnostic evaluationInitial evaluation depends on likely etiology
1. Chest Xray: hyperinflation, SOL,
s/o chronic diseases like
bronchiectasis, focal infiltrates
2. Trial of bronchodilators-
diagnostic & therapeutic in
bronchiolitis & asthma, won’t effect fixed obstruction
May worsen wheezing in tracheal/ bronchomalacia
3. Baseline immunity in complicated cases
Exclude other conditions
4) Structural problems: bronchoscopy
5) URTD : Polysomnography
6) Esophageal disease: Barium swallow, pH probes, Upper GI scopy
7) Primary ciliary dyskinesia: nasal ciliary motility, Exhaled NO,
Electron Microscopy, saccharine test
8) TB: mantoux, induced sputum/ gastric lavage/ BAL = Culture,
microscopy & PCR
9) Bronchiectasis: HRCT scan, BAL
10) CF: sweat test, nasal potentials, genotypes
11) Systemic immune deficiency: Ig subtypes,
lymphocytes & neutrophil function, HIV
12) Cardiovascular disease: echo, angiography
13) Viral testing (PCR, viral culture) is helpful if diagnosis
is uncertain.
Treatment
1) Comfort the child –
Try to keep your baby calm. Having a cough and a
noisy wheeze frightens children and breathing is
more difficult when they are upset.
2) Offer frequent liquids –
Drinking less but more often may be easier
3) Bronchodilators:
- administer inhaled short acting beta-2 agonist
(eg salbutamol) & observe the response
- Children < 3 yrs: inhaled medications by MDI
with mask & spacer, if therapeutic benefit
demonstrated
- response is unpredictable
- Therapy to be continued in all asthma
patients with exacerbations with viral
illness
4) Ipratropium bromide:
- can be used as adjunct therapy
- also useful in patients with significant tracheal or
bronchomalacia
- Anticholinergic agent
5) Oral/ IV steroids:
- used for atopic wheezing infants thought to have
asthma i.e. refractory to other medications
6) Inhaled steroids:
- appropriate for maintenance therapy in known reactive
airways but not useful in acute illness
- to be used if significant h/o atopy ( food allergy, eczema)
present
- maintenance treatment with inhaled steroids is
recommended for multiple-trigger wheeze.
7) In acute bronchiolitis:
- hospitalze
- mainstay of treatment is supportive
- hypoxemic child: cool humidified oxygen
- avoid sedatives
- keep head & chest elevated at 30 degree angle
- NG tube feeds to avoid aspiration
- resp decompensation tracheal intubation
- Bronchodilators show modest short term
improvement in clinical features
- Nebulized epinephrine more effective
8) Montelukast is recommended for the treatment of
episodic (viral) wheeze,to be started when symptoms of a
viral cold develop
9) Ribavarine: antiviral administered by aerosol
- Used for children with CHD/ CLD
10) No role of antibiotics unless secondary bacterial
infection
Prevention 1) Reduction in severity & incidence of ac. bronchiolitis due to
RSV is possible through administration of pooled Hyperimmune
RSV Intravenous Immunoglobulin (RSV IVIg, Respigam) and
2) Palivizumab, a monoclonal antibody to the RSV F protein, before &
during RSV season
It is recommended for children < 2yrs age with chronic lung disease
(BPD) or prematurity
3) Inhaled corticosteroids and montelukast may be
considered in preschool child with recurrent wheeze.
4) Avoid smoking –
Smoking in the home or car increases the risk of respiratory
problems in children
5) Educating parents regarding causative factors and
treatment is useful.
6) Allergen avoidance may be considered when sensitisation
has been established
7) Meticulous handwashing is the best measure
to prevent nosocomial infection
Prognosis Approx 60% of infants who wheeze, will stop wheezing
Ac. Bronchiolitis: highest risk in 1st 2-3 days ; Case Fatality Rate < 1%
Death apnea, severe dehydration, uncompensated resp acidosis
Mean duration of symp - 12 days
High incidence of wheezing & asthma in children with h/o
bronchiolitis
CHD/ BPD/ Immuno-deficiency:
More severe disease, higher morbidity & mortality
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