DIAGNOSTIC PITFALLS IN PEDIATRIC
BRONCHIAL ASTHMA
Ibrahim A. Janahi, MD, FCCP, FRCPCH
Professor of Clinical Pediatrics, Weill
Cornell Medicine- Qatar
Division Chief, Pediatric Pulmomnology
Learning points
What is asthma/Differential diagnosis of wheezy chest
Asthma diagnosis
• Definition and overarching principles
• Predictive index of asthma
• Approach to establish asthma diagnosis
• Organization of diagnostic services
• Wheezing in pre-school children and persistent asthma
Pitfalls in asthma diagnosis
• Pitfalls/Remedies
• Take home message
WHAT IS ASTHMA /
DIFFERENTIAL DIAGNOSIS
Asthma….?
A heterogeneous disease, usually characterized
by chronic airway inflammation.
Recurrent episodes of:
• wheezing
• Shortness of breath
• Chest tightness/pain
• Coughing
This happens as a response to a trigger. It varies
over time and in intensity, together with variable
expiratory airflow limitation
Asthma Phenotypes
Causes of wheezing in children and infants
DEFINITION AND
OVERARCHING PRINCIPLES
Definition
• Diagnosis is defined as the presence of symptoms (more
than one of wheeze, breathlessness, chest tightness, cough)
and of variable airflow obstruction on chronic and recurrent
basis (more than 6-8 weeks)
• More recent descriptions of asthma have included
airway hyper-responsiveness
airway inflammation as components of the disease reflecting
a developing understanding of the diverse subtypes
(phenotypes and endotypes) of asthma.
• Wheezy chest has many differential diagnosis which might
be confusing to clinicians if not following a diagnostic
algorithm to confirm the diagnosis.
Overarching Principles of Asthma Diagnosis
1. Asthma diagnosis is based on clinical assessment + supported by
objective tests.
2. In patients with a very high probability of asthma prior to testing,
the results of a diagnostic test with a substantial false negative
rate will have minimal influence on the diagnosis.
3. In patients with an intermediate or low probability of asthma, a
positive diagnostic test may significantly shift the probability
towards an asthma diagnosis.
Tests influence the probability of asthma but do not prove the diagnosis:
Overarching Principles
Asthma status and the outcome of diagnostic tests for asthma
vary over time
1. Patients who have not received prescriptions for a year are
considered to be ‘inactive’, some patients may shift from
‘inactive’ to ‘active’ status (and vice versa) over time.
2. Objective tests performed when patients are asymptomatic or
during an ‘inactive’ period may result in false negatives.
Golden Rule
Compare the results of diagnostic tests undertaken whilst a patient is
asymptomatic with those undertaken when a patient is symptomatic to
detect variation over time.
Predictive Value
(symptoms, signs and diagnostic
tests)
Asthma Predictive Index
• It is a guide to determining which individual will develop
asthma in later years.
• Children younger than 3 years who have had four or
more significant wheezing episodes over the past year
are much more likely to have persistent asthma after the
age of five.
Predictive values
i. Test of Variability in lung functions
ii. Spirometry and bronchodilator
reversibility
- Combination of symptoms and signs will
be more helpful to accurately diagnose
rather than isolated ones.
Carry out quality-assured spirometry using
the lower limit of normal to
demonstrate airway obstruction, provide a
baseline for assessing response
to initiation of treatment and exclude
alternative diagnoses.
- Only “Quarter” of children who have
asthma signs were proven to be
asthmatic.
- Episodic nature of symptoms as opposed
to current symptoms may improve the
predictive value.
- Wheezy chest should be well
distinguished from noisy breathing or
stridor.
• Obstructive spirometry with positive
bronchodilator reversibility increases the
probability of asthma.
• Normal spirometry in an asymptomatic
patient does not rule out the diagnosis of
asthma.
iii. Tests of variability in lung function
iv. Tests to detect eosinophilic airway
inflammation or atopy
Direct challenge tests: (highly predictive)
A negative test in a child, makes a diagnosis of
asthma improbable.
Fractional exhaled nitric oxide (FeNO)
 Use measurement of FeNO (if available) to find
evidence of eosinophilic inflammation.
 A positive test increases the probability of asthma
but a negative test does not exclude asthma.
Indirect challenge tests (highly predictive)
 A positive response as a fall in FEV1of
greater than 15%, is a specific marker of
asthma
 In children, a positive challenge test is highly
predictive of asthma with a false positive rate
of less than 10%, while the negative excludes
it.
Peak expiratory flow monitoring
There is no evidence to support the routine use
of peak flow monitoring in the diagnosis of
asthma in children.
Tests of atopic status
Use a previous record of skin-prick tests, blood
eosinophilia of 4% or more,
or a raised allergen-specific IgE to corroborate a
history of atopic status, but do not offer these tests
routinely as a diagnostic test for asthma.
Sputum eosinophils
Induced sputum in school age children is more of a
research than a diagnostic tool.
Approach to Establish Asthma
Diagnosis
Initial Structured Clinical Assessment
Undertake a structured clinical assessment to assess
the initial probability of asthma. This should be based
on:
• History of recurrent episodes (attacks) of symptoms,
ideally corroborated by variable peak flows when
symptomatic and asymptomatic.
• Symptoms of wheeze, cough, breathlessness and chest
tightness that vary over time.
• Recorded observation of wheeze heard by a healthcare
professional.
• Personal/family history of other atopic conditions.
• No symptoms/signs to suggest alternative diagnoses.
Approach to Establish Asthma Diagnosis
Initial structured clinical assessment.
 High probability of asthma based on initial
structured clinical assessment.
 Low probability of asthma based on initial
structured clinical assessment.
 Intermediate probability of asthma based on initial
structured clinical assessment.
High Probability of Asthma Based on Initial
Structured Clinical Assessment
• Record the patient as likely to have asthma and commence a
carefully monitored initiation of treatment (typically six weeks of
inhaled corticosteroids).
• Assess the patient’s status with a validated symptom
questionnaire, ideally corroborated by lung function tests.
• With a good symptomatic and objective response to treatment,
confirm the diagnosis of asthma and record the basis on which
the diagnosis was made.
• If the response is poor or equivocal, check inhaler technique and
adherence, arrange further tests and consider alternative
diagnoses.
Low Probability of Asthma Based on Initial
Structured Clinical Assessment
• If there is a low probability of asthma and/or an
alternative diagnosis is more likely, investigate for
the alternative diagnosis and/or undertake or refer
for further tests of asthma.
Intermediate Probability of Asthma Based on Initial
Structured Clinical Assessment
• Spirometry, with bronchodilator reversibility, is the preferred initial
test for investigating intermediate probability of asthma in adults,
and in children old enough to undertake a reliable test.
• In children with an intermediate probability of asthma and airways
obstruction identified through spirometry; undertake reversibility
tests and/or a monitored initiation of treatment assessing the
response to treatment by repeating lung function tests and
objective measures of asthma control.
• In children with an intermediate probability of asthma and normal
spirometry results; undertake challenge tests and/or measurement
of FeNO to identify eosinophilic inflammation.
In children with an intermediate probability of
asthma who cannot perform spirometry:
• Consider watchful waiting if the child is asymptomatic
• Offer a carefully monitored initiation of treatment if the
child is symptomatic.
Diagnostic Algorithm
Indications for Referral
Organization of Diagnostic
Services
Diagnostic Services …
Streamline referral pathways should be developed for
tests not available or appropriate in primary care.
• Simple tests as spirometer and bronchodilator reversibility
mostly will be available in primary care centers.
• FENO and skin prick test are available in secondary care.
• Challenge test will require referral to a diagnostic center
(tertiary care).
Wheezing in Preschool
Children and Future Risk of
Persistent Asthma
Factors Associated with High / low Risk of
Persistent Asthma Development
• Age at presentation
• Sex
• Severity and frequency of previous wheezing
episode
• Coexistence of atopic disease
• Family history of atopy
• Abnormal lung function
Pitfalls in Asthma Diagnosis
Most common Pitfalls in Asthma Diagnosis
1.
2.
3.
4.
5.
Under-diagnosis of Asthma.
Ineffective inhalation therapy.
Ignoring concomitant disorder.
Ignoring common risk factors/triggers.
Failure to deliver asthma education.
1. Under-diagnosed Asthma
2. Ineffective Inhalation Therapy
3. Ignoring Concomitant Disorder
4. Ignoring Common Risk Factors / Triggers
5- Failure to Deliver Asthma Education
Take home message
Take home message
Case (1)
• 14 year old girl presents with history of recurrent attacks of
shortness of breath associated with wheezing for the last 2 years.
These attacks occur when she is exposed to certain perfumes but
she can’t pinpoint which ones. They occurred 4 times in the last 2
years each one of them lasting few hours and responding fairly
well upon taking salbutemol inhalers that she borrows from her
elder brother who has asthma.
• She reports annoying dry nocturnal cough that has not gone away
since it started few months ago. The cough some times wakes her
up from sleep early morning; at one stage she tried taking
salbutemol inhaler for this cough and she noticed improvement
and thus decided to use the inhaler whenever the cough is “very
bad”
• Her physical examination in normal apart from slight increase in
the AP diameter of her thorax.
Case (1) Questions
1. What is the most likely diagnosis?
2. How would you confirm the diagnosis?
3. How would you treat this girl?
Case (2)
• 2 year old boy is brought to your clinic because he has been having
recurrent episodes of wheezing and shortness of breath for the last
2 years. These episodes occur on monthly basis, mainly with URTIs
but some times without a trigger that the mother could pinpoint
• He first started to have these episodes when he was 10 months old
when he was admitted to the PEC for a day to treat a “bad” episode
of “chest infection”. You noted form the EMR that he was then
positive for Rhino Virus infection
• These episodes respond quite dramatically to salbutemol
nebulizations but some times he has to continue using the nebs for
3-4 days till he gets “completely clear”
• He is followed at the dermatology clinic for a “stubborn” eczema
• His elder brother (12 year) used to have “asthma” when he was
younger but he “outgrew it”
• His physical examination today is completely normal
Case (2) Questions
1. What is your diagnosis?
2. Can you confirm the diagnosis? And how?
3. How would you treat this child?
References
• The Diagnosis of Wheezing in Children LISA NOBLE WEISS, MD, MEd, Northeastern
Ohio Universities Colleges of Medicine and Pharmacy, Forum Health Family Practice
Center, Youngstown, OhioAm Fam Physician. 2008 Apr 15;77(8):1109-1114.
• Asthma: tips and pitfalls in diagnosis and treatment.Volume 21, Issue 15-16, Version
of Record online: 27 AUG 2010 m http://onlinelibrary.wiley.com/doi/10.1002/psb.658/pdf
• Pitfalls in the Management of Bronchial Asthma Medicine Update 2008 Vol. 18
http://citeseerx.ist.psu.edu/viewdoc
download;jsessionid=1B70F5B10EB971F24D66B7D163410FBE?doi=10.1.1.689.3978&re
p=rep1&type=pdf.
• British guidelines on the management of asthma; a national clinical guideline. SIGN
153-September 2016 http://www.sign.ac.uk/pdf/SIGN153.pdf
Thank You