Os 213 Pediatric Asthma

OS 213: Pulmunology

Maria Liza B. Zabala, M.D. Exam 1

Pediatric Asthma

Lecture Outline

I. II. III. IV. V. VI. VII.

Epidmemiology Definition Review of Anatomy Pathophysiology Risk Factors Clinical Features/Diagnosis Management

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Primary physiologic manifestation is spontaneously variable airway obstruction which can be modulated by:  Increased obstruction caused by many stimuli  Alleviation of obstruction by bronchodilators and/or anti-inflammatory agents

REVIEW OF ANATOMY

EPIDEMIOLOGY 

Asthma ranked number 1 among the noninfections admissions in 57 of accredited hospitals PPS Registry of Diseases, 1994

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Prevalence of wheezing among 6-19 years in Metro Manila schools was 27.45% Del Mundo, textbook of Pediatrics 2002

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A large international survey study of childhood asthma prevalence in 56 countries found a wide range in asthma prevalence, from 1.6 to 36.8% ISAAC Study

Source: Masoli M et al. Allergy 2004 DEFINITION 

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a chronic inflammatory disorder of the airways in which many cells play a role, including mast cells and eosinophils this inflammation causes symptoms that are usually associated with widespread but variable airflow obstruction that is often reversible either spontaneously or with treatment, and causes associated increase in airway hyperresponsiveness to a variety of stimuli. a disorder defined by its clinical, physiological and pathological characteristics Clinically, asthma is characterized by airway hyperresponsiveness presenting as widespread narrowing of the airway which results from a variety of stimuli like allergens, exercise, physical factors and irritant gases

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PATHOPHYSIOLOGY is complex and involves the following components: 1) 2) 3)

Airway inflammation Intermittent airflow obstruction Bronchial hyperresponsiveness

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OS 213: Pulmunology

Maria Liza B. Zabala, M.D. Exam 1

Pediatric Asthma

Asthma Inflammation: Cells and Mediators

Key Mediators of Asthma: 

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Chemokines  recruitment of inflammatory cells into the airways and are mainly expressed in airway epithelial cells Cysteinyl leukotrienes  potent bronchoconstrictors and proinflammatory mediators mainly derived from mast cells and eosinophils  only mediator whose inhibition has been associated with an improvement in lung function and asthma symptoms Cytokines  orchestrate the inflammatory response in asthma and determine its severity Histamine  contributes to bronchoconstriction and to the inflammatory response Nitric Oxide  a potent vasodilator, produced predominantly from the action of inducible nitric oxide synthase in airway epithelial cell

Asthma Inflammation: Cells and Mediators

Mechanisms Of Airway Narrowing in Asthma 

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Contraction of Airway smooth muscle (ASM) is the predominant mechanism largely reversed by bronchodilators Airway wall thickening Accumulation of airway secretions, mucus casts, and cellular debris may partially occlude the lumen

Regulation of Airway Caliber  Cholinergic (parasympathetic) motoneurons innervate the airways via the vagus nerve  Nonadrenergic Noncholinergic (NANC) Nervous system  NANC system neurons in the vagus nerve release the peptides, SUBSTANCE P and VASOACTIVE INTESTINAL PEPTIDE  Appears to be the most potent relaxant component of the nervous system involved in regulation of airway diameter Factors that Influence Asthma Development and Expression Host Factors  Genetic  Atopy  Airway hyperresponsiveness  Gender  Obesity Environmental Factors  Indoor allergens  Outdoor allergens  Occupational sensitizers  Tobacco smoke  Air Pollution  Respiratory Infections  Diet RISK FACTORS FOR ASTHMA  

Host factors: predispose individuals to, or protect them from, developing asthma Environmental factors: influence susceptibility to development of asthma in predisposed individuals, precipitate asthma exacerbations, and/or cause symptoms to persist

Who gets asthma? Anyone!!!  Most children develop asthma before age 8 years and over half before 3 years

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OS 213: Pulmunology

Maria Liza B. Zabala, M.D. Exam 1

Pediatric Asthma

 30% < 1 year   

80-90% before 4-5 years old Before puberty: asthma occurs 11/2-3x male > female Adolescence male=female

Predisposing Factors involved in the Development of Asthma 

Atopy 

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defined as the preponderance to produce abnormal amounts of IgE in response to environmental allergens Familial association among asthma, allergic rhinitis and atopic dermatitis suggests a common genetic basis -chromosomes 5, 11 90% of asthmatic children have an allergic component 64-84% (+) family history of asthma among 1st degree relatives 30% & 3.5% of asthmatic patients reported asthma in one parent and in none respectively

Upper airway noise/congestion Cystic fibrosis (CF) Gastroesophageal reflux disease (GERD) Bronchopulmonary dysplasia (BPD) Foreign body aspiration Immunodeficiency (ID) Vocal cord dysfunction

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CLINICAL FEATURES Frequent episodes of wheeze (more than once a month) Activity induced cough or wheeze Nocturnal coughs in periods without viral infections Absence of seasonal variations in wheeze Symptoms that persist after the age of 3 Wheeze before the age of 3 and one major risk factor  parental history of asthma or eczema or two or three risk factors (eosinophilia, wheezing without colds, and allergic rhinitis) has been shown to predict the presence of asthma in later childhood

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Gender  Male preponderance

Triggers 

Masqueraders of asthma in children

DIAGNOSIS Risk factors that cause asthma exacerbation by inducing inflammation or provoking acute bronchoconstriction or both

Signs and symptoms to look for include: Frequent coughing spells, which may occur during play, at night, or while laughing. It is important to know that cough may be the only symptom present. Less energy during play Rapid breathing Complaint of chest tightness or chest "hurting” Whistling sound (wheezing) when breathing in or out See-saw motions (retractions) in the chest from labored breathing Shortness of breath, loss of breath Tightened neck and chest muscles Feelings of weakness or tiredness

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Trigger Factors of Asthma in Various Age Groups        

Anatomic and physiologic peculiarities that predispose to obstructive airway disease 1. 2. 3. 4. 5.

6. 7.

Decreased amount of smooth muscle in peripheral airways Mucosal gland hyperplasia in the major bronchi compared to adults favors increased intraluminal mucus production Disproportionately narrow peripheral airways up to 5 years of age Decreased static elastic recoil of the young lung predisposes to early airway closure during tidal breathing Highly compliant rib cage and mechanically disadvantageous angle of insertion of diaphragm to ribcage increases diaphragmatic work of breathing Decreased number of fatigue-resistant skeletal muscles in the diaphragm Deficient collateral ventilation with the pores of Kohn and the Lambert canals deficient in number and size

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Spirometry 

Recommended in the initial assessment of patients suspected to have asthma

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OS 213: Pulmunology

Maria Liza B. Zabala, M.D. Exam 1

Pediatric Asthma

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Usually feasible in children from age >5 years Useful in assessing  Degree of airway obstruction  Disturbances in gas exchange  Response of airways to inhaled allergens/ chemicals/exercise  Assessing response to therapeutic agents  Evaluating long-term course of disease FEV1 is the single best measure for assessing severity of airflow obstruction FEV1 measurements <80% of predicted value is evidence of airway obstruction and reversibility with use of inhaled ß2-agonist (increase in FEV1 by 15%) makes a definitive diagnosis of asthma

Diagnosis of Asthma  1) 2) 3) 4)

Other Tests to help establish the diagnosis of asthma Methacholine/Histamine bronchoprovocation test Exercise challenge test Twice daily recording of peak flow to determine diurnal variation Therapeutic trial of five days steroid and bronchodilator course

Portable Peak Flow Meter   

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measure PEFR where spirometry is not available less sensitive, but correlates well with FEV1 offers an acceptable alternative to assess response to exercise challenge and peak flow variability The predicted normal PEFR for Filipino children between 6 and 17 years of age with height of at least 100 cm can be calculated:  Males: (Height in cm - 100) 5 + 175  Females: (Height in cm - 100) 5 + 170

MANAGEMENT “Basically longterm, involving both pharmacological and non pharmacological interventions” Philippine Consensus Report 2002 Goals of Therapy 1.

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to maintain normal activity levels including exercise;

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OS 213: Pulmunology

Maria Liza B. Zabala, M.D. Exam 1

Pediatric Asthma

2. 3. 4. 5.

to maintain ( near ) normal pulmonary function test; to prevent chronic and troublesome symptoms; to prevent recurrent exacerbations; and, to avoid adverse effects from asthma medications

Components of asthma care 1) 2) 3) 4)

Develop patient/doctor partnership Identify and reduce exposure to risk factors Assess, treat and monitor asthma Manage asthma exacerbations

Outcome Successful management of asthma should lead to an improvement or normalization of the child’s daily activities, respiratory symptoms, pulmonary function and personal and family psychosocial functioning. Richel: Haaaaaay. High stress itong trans na to. Half pa lang ng coverage ang nababasa ko :s at kailangan ko pa tong unahin, kaya basahin niyo to! Hello octetmates! Goodluck tom. Haha. :D

Objectives IDEAL MINIMAL Minimal or no chronic symptoms Least symptoms Minimal episodes Least need for PRN β2- agonist No ER visits Least limitation of activity Minimal need for PRN β2- agonist No limitation on activities Best PEFR PEF circadian variation < 20% Least adverse effects ( Near) normal PEF Minimal or no adverse effect

Long-term Management of Asthma in Children ASSESSMENT Asthmatic child is classified to an asthma severity category Category of severity will suggest the initial pharmacologic treatment Pharmacologic therapy is described as “step care”  control of symptoms should be established as soon as possible  short course of oral corticosteroids or higher doses of inhaled corticosteroids may be considered for faster control  therapy should be decreased as soon as possible to that which is required based on the identified asthma severity category On follow up:  if control is attained and sustained for at least three months, a gradual reduction in treatment may be possible  if control is not achieved within 2-6 weeks  review patient’s inhaler technique  review compliance and environmental control measures (such as: avoidance of allergens or other triggers)  diagnosis should be re-evaluated and treatment should be advanced to the next step *see Appendix for long term management Monitoring to maintain control • Control should be monitored to maintain control and establish lowest step and dose

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Should be seen one to three months after the initial visit and every 3 months thereafter After an exacerbation, follow-up should be within two weeks to one month

ALLERGEN IMMUNOTHERAPY IN ASTHMA • Administration of increasing quantities of specific allergic extracts to patients with IgE-mediated allergic rhinitis, asthma or stinging insect anaphylaxis • Should be considered o avoiding allergens is not possible o less than complete control of symptoms is achieved with bronchodilators or inhaled steroids • Greatest benefit of specific immunotherapy using allergen extracts has been obtained in the treatment of allergic rhinitis • Role of specific immunotherapy in asthma is limited • Specific immunotherapy should be considered only after strict environmental avoidance and pharmacologic intervention, including inhaled glucocorticosteroids, have failed to control asthma • Performed only by trained physician MANAGING EXACERBATIONS OF ASTHMA Exacerbations of asthma • Acute or sub-acute episodes of progressively worsening symptoms of shortness of breath, cough, wheeze and chest tightness or a combination of these • Exacerbations may be mild, moderate severe or even life threatening Key points • Prevention of exacerbations is the optimal goal

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Severity of future attacks cannot be predicted, thus early recognition is imperative Note: most cases of asthma morbidity and mortality are due to underassessment and undertreatment • In the event of an attack, early treatment is advised o Recognition of early signs of attack or worsening asthma o Appropriate use of relievers o Prompt communication between patient and physician • Management of asthma attack may include, but is not limited to: o Inhaled short-acting β2 agonist for immediate relief of airway obstruction o Systemic corticosteroids o Oxygen o Other agents (e.g. ipratropium bromide, theophylline) Note: close monitoring of patient’s condition as well as response to therapy is crucial Anticholinergics • Recent studies have shown that anticholinergics (e.g. ipratropium bromide) offer some benefit when used early and in combination with shortacting β2 agonists

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In children with acute asthma, addition of anticholinergics to inhaled β2 agonists for 3 doses given every 20 minutes appears to

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OS 213: Pulmunology

Maria Liza B. Zabala, M.D. Exam 1

Pediatric Asthma

improve lung function modestly and decrease hospital admissions. High risk patients These are the patients who have the potential to go into sudden and severe airway obstruction which may lead to respiratory failure or death. They should be educated to seek medical care early during an exacerbation. • infants in moderate/severe exacerbation • current use or recent withdrawal (< 1 week) from systemic corticosteroids • hospitalization for moderate or severe asthma in the past year • prior intubation or history of impending respiratory failure from asthma • psychiatric disease or psychosocial problems • difficulty perceiving airflow obstruction or its severity, and • non-compliance with asthma medication plan IMMEDIATE CASE OF ASTHMA EXACERBATIONS • Treatment should be started as soon as an asthma attack is recognized. • Initial treatment will include inhaled short-acting

β2 and if necessary, oxygen. o PE should be done to determine

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severity of exacerbation to serve as a guide to the type of management appropriate for the case. Brief but focused history pertinent to the attack

Pertinent points to ask • Severity of symptoms • History of prior attacks • Visits to the emergency room • Hospitalization (including history of intubation) due to asthma • Current medications • Any of other complicating illnesses (e.g. other pulmonary or cardiac problems) Particular attention should be given to patients who present with the following features, as they are the ones most prone to develop acute respiratory failure: • Cyanosis • absence of wheeze • bradycardia and bradypnea • paradoxical thoraco-abdominal movement • drowsiness or confusion • a normal or elevated pCO2 in a patient with severe distress Appendix. Severity of Asthma Exacerbations Admission to Intensive Care Unit Recommended in the following situations: 1) progressive worsening of asthma symptoms despite initial Management 2) presence of sensorial changes (drowsiness, confusion) or loss of consciousness 3) signs of respiratory fatigue (e.g. declining respiratory rate) 4) impending respiratory arrest (paO2 < 60 mmHg on supplemental oxygen, pCO2 > 45 mmHg)

From the Emergency Room 1) symptoms are absent or minimal 2) PEFR > 80% predicted 3) sustained response for at least four (4) hours From the Hospital 1) physical examination is normal or near normal 2) no nocturnal awakenings 3) PEFR > 80% predicted 4) sustained response to inhaled short-acting β2 agonist (at least 4 hours) Discharge Instructions  Identify and avoid the trigger(s) that precipitated the attack  Prescribe sufficient medications to continue treatment after discharge  Review inhaler technique  If peak flow meter is available, provide an action plan  Emphasize regular, continuous follow-up with the physician Drug Therapy 2 TYPES  RESCUE/RELIEVER -for acute relief of symptoms  PROPHYLACTIC/CONTROLLER -to prevent exacerbations 

RELIEVER

-bronchodilators which relax airway muscles that tighten in and around the airways -provide quick relief of symptoms but does not treat underlying airway inflammation Reliever Medications:  Rapid-acting inhaled beta2-agonist  Systemic glucocorticosteroids  Anticholinergics  Theophylline  Short-acting oral beta2-agonist 

CONTROLLER

-Consists of anti-inflammatory agents which prevent asthma attacks by reversing the underlying inflammatory changes -Prevents further inflammation of airways and controls chronic symptoms Controller Medications:  Inhaled glucocorticosteroids  Leukotriene modifiers  Long-acting inhaled β2-agonists  Systemic glucocorticosteroids  Theophylline  Cromones  Long-acting oral β2-agonists

 Anti-IgE 

Systemic glucocorticosteroids

Patient Discharge

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OS 213: Pulmunology

Maria Liza B. Zabala, M.D. Exam 1

Pediatric Asthma

On your way to ER, continue your quick relief inhaled bronchodilator every 20 minutes and take 1 dose of oral steroids _________ RED ZONE: EMERGENCY!!! - Presence of any:(Trouble walking or talking due to shortness of breath, lips and fingernails are blue) -Quick relief medicines have not helped -Cannot do usual activities -Symptoms are getting worse -Peak flow meter: _____ (< 60 % of your personal best)

Key Points to Inhalational Devices 1) There is little difference in the therapeutic effect between a correctly used MDI with or without a spacer, DPI, and a nebulizer 2) MDI spacer can increase ling deposition 3) MDI spacer can decrease oropharyngeal deposition 4) MDI with a spacer, DPI, or nebulizers can be used for patients who have difficulty coordinating with MDI activation, those with optimal breathing pattern, in children, and patients with severe illness Non-pharmacologic interventions include  Environmental control  Monitoring of the status of the disease  Asthma education

ACTION: - Proceed to ER - Take immediately 1 dose of your quick relief inhaled bronchodilator and continue your inhaled bronchodilator every 20 minutes while in transit - Take 1 dose oral steroids __________ *may mga blanks talaga yan ha ;) References Philippine Consensus For The Management Of Childhood Asthma Revised 2002  Global Initiative For Asthma Revised 2006  Nelson Textbook of Pediatircs  Lippincott’s Pathophysiology Series Pulonary Pathophysiology 1995 By Michael Grippi  Textbook Of Pediatric and Health Care 4th Edition By Del Mundo  Kendig’s Disorders of the Respiratory Tract in Children 7th Edition 

Action Plan The asthma action plan is a written asthma management plan that is jointly prepared by the doctor and the patient. This written instruction to the patient should be updated every visit as changes in peak flow measurements or asthma severity category may occur. GREEN ZONE: Doing Well - No symptoms day and night (cough, wheeze, chest tightness and shortness of breath) - Can do usual activities - Peak flow meter __________ (>80 % of your personal best or predicted)

Richel: Greetings ulit  Hello Phinoms!  Sarap ng potatoes no? Hehe. Saka na ulit yung next supply. Family day ulit? :p Tinatamad na ako bumati, hello na lang to everyone! Malunggays, sana matapos na natin itong research. Pahiraaaaaaaap. :D Happy birthday Lani, Fides, and Dr.Gana! :D Hello Raphael. Thank you 

ACTION: - Continue with your current medication as prescribed _________ YELLOW ZONE: Acute Attack - Presence of at least 1 of the following: (cough, wheeze, chest tightness or shortness of breath) - Waking at night due to asthma - Can do some but not all usual activities - Peak flow meter: _____ to _____ (60 to 79% of your personal best) ACTION: -Take your quick-relief inhaled brochodilator_______________ every 20 minutes up to 3 doses until relieved - Proceed to ER for further evaluation & possible admission if: 1. getting worse at anytime 2. if no relief after 3 doses of inhaled β2 agonist

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OS 213: Pulmunology Pediatric Asthma

Dec 11, 2008 | Thursday

Maria Liza B. Zabala, M.D. Exam 1

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