1. www.pediatricianonline.in GSMC KEMH
ROAD + BHR
chronic inflammatory disorder of the airways characterized by an obstruction of airflow, which may be completely or partially reversed with or without specific therapy
Airway inflammation is associated with airway hyper reactivity or bronchial hyper responsiveness (BHR), which is defined as the inherent tendency of the airways to narrow in response to a variety of stimuli (e.g., environmental allergens and irritants).
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Pathophysiology
Environmental and genetic factors
Allergens, GER, weather change, Allergic rhinitis, sinusitis, and chronic URTI
Airway inflammation, bronchospasm, mucosal edema, and mucus plugs
Increased resistance to airflow and decreased expiratory flow rates
Hyperinflation and later alveolar hypoventilation
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Pathophysiology 2
In the early stages of an acute episode, ventilation-perfusion mismatch => results in hypoxia, No hypercarbia.
respiratory alkalosis results from hyperventilation.
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With worsening obstruction and increasing ventilation-perfusion mismatch => carbon dioxide retention
Increased work of breathing, increased oxygen consumption, and increased cardiac output result in metabolic acidosis. Respiratory failure leads to respiratory acidosis.
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4. New insights in the pathogenesis of asthma
a loss of normal balance between two "opposing" populations of Th lymphocytes
Th1 produce IL-2 and IFN-a, which are critical in cellular defense mechanisms in response to infection.
Th2 produce a family of cytokines (IL-4, -5, -6, -9, and -13) that can mediate allergic inflammation.
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5. "hygiene hypothesis" of asthma
immune system of the newborn is skewed toward Th2 cytokine generation.
Following birth, environmental stimuli such as infections will activate Th1 responses and
bring the Th1/Th2 relationship to an appropriate balance.
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6. genetic background of cytokine imbalance
Early asthmatic responses occur via IgE-induced mediator release from mast cells within minutes of exposure and last for minutes.
Late asthmatic responses occur 4-12 hours after antigen exposure and result in more severe symptoms that can last for hours and contribute to the duration and severity of the disease.
Inflammatory cell infiltration and inflammatory mediators play a role in the late asthmatic response.
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7. www.pediatricianonline.in GSMC KEMH
prevalence
Was 5%, and it has increased 20-40% in the past decade
Worldwide, 130 million people have asthma.
The prevalence is 8-10 times higher in developed countries (eg, United States, Great Britain, Australia, New Zealand) than in the developing countries.
Before puberty, the prevalence is 3 times higher in boys than in girls.
In most children, asthma develops before they are aged 5 years
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Clinical patterns
Among infants, 20% have wheezing with only upper respiratory tract infections (URTIs), and 60% no longer have wheezing when they are aged 6 years
"transient wheezers"
Children in whom wheezing begins early, in conjunction with allergies, are more likely to have wheezing when they are aged 6 and 11 years.
Similarly, children in whom wheezing begins after they are aged 6 years often have allergies, and the wheezing is more likely to continue when they are aged 11 years.
Cough variant asthma, exerxise induced asthma, nocturnal asthma
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National Asthma Education and Prevention Program US "Guidelines for the Diagnosis and Management of Asthma"
(a) episodic symptoms of airflow obstruction are present,
(b) airflow obstruction or symptoms are at least partially reversible, and
(c) alternative diagnoses are excluded.
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severity of asthma
Mild intermittent,
Mild persistent,
Moderate persistent, or
Severe persistent,
According to the frequency and severity of symptoms, including nocturnal symptoms, characteristics of acute episodes, and pulmonary function.
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11. www.pediatricianonline.in GSMC KEMH
mild intermittent
symptoms fewer < than 2 times a week
pulmonary function is normal between exacerbations.
Exacerbations are brief, lasting from a few hours to a few days
Nighttime symptoms occur less than twice a month
variation in peak expiratory flow (PEF) is less than <20%.
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mild persistent
Symptoms more than 2 times a week but less than once a day.
Exacerbations may affect activity.
Nighttime symptoms occur more than twice a month.
(FEV1) is less than 80% of the predicted value, and the variation in PEF is 20-30%.
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13. www.pediatricianonline.in GSMC KEMH
moderate persistent
Daily symptoms
Exacerbations more than 2 times a week and last for days. affect activity
Nocturnal symptoms occur more than once a week
FEV % of the predicted values, and PEF varies by more than 30%.
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14. www.pediatricianonline.in GSMC KEMH
severe persistent
Continuous or frequent symptoms
limited physical activity, and
frequent nocturnal symptoms
FEV1 less than 60% of the predicted values, and varies by more than 30%.
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15. Wheezing ≠ asthma, not synonymous
A musical, high-pitched, whistling sound produced by turbulence
Initially, wheezing is only end expiratory => then throughout expiration. => during inspiration => During a most severe episode, wheezing may be absent
Asthma can occur without wheezing
Wheezing can be associated with other causes of airway obstruction
Patients with vocal cord dysfunction have a inspiratory monophonic wheeze (different from the polyphonic wheeze in asthma), which is heard best over the laryngeal area in the neck. Patients with bronchomalacia and tracheomalacia also have a monophonic wheeze.
In exercise-induced or nocturnal asthma, wheezing may be present after exercise or during the night, respectively.
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symptoms
typical symptoms of wheezing, coughing, and chest tightness
shortness of breath, and
coughing after exposure to allergens, environmental irritants, viruses, cold air, or exercise.
with chronic asthma, airflow limitation may be only partially reversible because of airway remodeling
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17. www.pediatricianonline.in GSMC KEMH
Coughing
May be the only symptom
Especially in cases of exercise-induced or nocturnal asthma.
Nonproductive and nonparoxysmal
Coughing may be present with wheezing
Children with nocturnal asthma tend to cough after midnight, during the early hours of morning.
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18. Recurrent respiratory….=> HRAD
history of recurrent bronchitis,
bronchiolitis, or
pneumonia;
a persistent cough with colds; and/or
recurrent croup or chest rattling.
chronic or recurrent bronchitis
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19. Clinical grading of breathlessness
Breathless on walking
Breathless on talking
Breathless at rest
Breathless => impending respiratory failure
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20. www.pediatricianonline.in GSMC KEMH
physical findings
normal findings
signs of chronic respiratory distress and chronic hyperinflation
Signs of atopy or allergic rhinitis
prolongation of the expiratory phase, expiratory wheezing, coarse crackles, or unequal breath sounds.
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physical findings
Mild
Moderate
Severe
Status
Tachypnea + ++
+++
May be arrest
Tachycardia
Upto 100
Pulsus Para
>120
Pulsus ParaD++
bradycardia
Accessory muscles/ retractions
None
Suprasternal
Suprasternal and subcostal with alae nasae
paradoxical
Auscultaion
End exp wheeze
Expiratory
Biphasic wheeze
No wheeze?
saturation
>95%
91-95%
<91%
Cyanosis?
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22. Investigations : > 5 yr age
PFT –spirometry
an obstructive defect is present in the form of normal forced vital capacity (FVC), reduced FEV1, and reduced forced expiratory flow over 25-75% of the FVC (FEF 25-75). The flow-volume loop can be concave.
PFT - plethysmography
an increased total lung capacity (TLC) at plethysmography. Increased residual volume (RV) and functional residual capacity (FRC)
Documentation of reversibility of airway obstruction after bronchodilator therapy is central to the definition of asthma.
Bronchial provocation tests may be performed to diagnose BHR Bronchial provocation tests may be performed to diagnose BHR with methacholine.
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Other investigations
Eosinophil counts and IgE levels
fraction of exhaled nitric oxide (FeNO) as a noninvasive marker of airway inflammation
Chest radiography
Paranasal sinus radiography or CT scanning
Allergy testing
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24. goals of asthma therapy
prevent chronic and troublesome symptoms,
maintain normal or near-normal pulmonary function,
maintain normal physical activity levels (including exercise),
prevent recurrent exacerbations of asthma, and
minimize the need for emergency department visits or hospitalizations,
provide optimal pharmacotherapy with minimal or no adverse effects, and
meet the family's expectations for asthma care.
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25. www.pediatricianonline.in GSMC KEMH
Nonpharma treatment
Allergen avoidance
Sitting posture with arm support
Open mouth breathing during an episode
Avoid congested crowded or high altitude areas with relative hypoxia
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26. Pharmacologic management
inhaled corticosteroids,
inhaled cromolyn or nedocromil,
long-acting bronchodilators,
theophylline,
leukotriene modifiers,
anti-IgE antibodies
Relief medications include
short-acting bronchodilators, systemic corticosteroids, and ipratropium.
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27. Plan: inhaled medicines > systemic
Episodic bronchodilators with or without steroids, upto 7 days following the episode MP
Regular steroids, with Episodic bronchodilators
MoP
Regular steroids and bronchodilators SP
Plus antininflammatory or modulant agents
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Inhalation devices
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for various pediatric medicine related tips.
mar 2007
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