Approach To A Child With AsthmaPresentation Transcript
APPROACH TO ACHILD WITH ASTHMA By: Dr.S.Krishnapradeep Registrar (Paed),SBSCH,Peradeniya
WHAT IS ASTHMA? It is a chronic inflammatory disorder of the airways characterized by an obstruction to airflow, which may be completely or partially reversible with or without specific therapy.
COMPONENTS OF ASTHMA1. Airway inflammation2. Bronchial hyper-responsiveness (BHR)3. Bronchospasm
Disability-adjusted life year for asthma per 100,000 inhabitants in 2004 DALY = YLL + YLD"Death and DALY estimates for 2004 by cause for WHO Member States: Persons, allages“.World Health Organization. 2002. Retrieved 2009-11-12.
EPIDEMIOLOGY 300 million individuals are effected. 15 million disability-adjusted life-years are lost and 250,000 deaths are reported. 150,000 paediatric hospitalizations. Before puberty M:F = 3:1 During adolescence M= F In majority, asthma develops before age 5 years, and in more than half before age 3 years.
ETIOLOGY Geneticso Hundreds of genes are associatedo 20p13 is associated with bronchial hyper responsivenesso Risk of transmission greater through mother than father Foodo In 25% triggered by foodo Common foods are peanut, milk, egg and tree nutso Fish-oil 3 fatty acid supplementation has no benefit
ETIOLOGY…….. Infectionso Rhinovirus & RSV are the most common causeso Low production of IFN-ß was noted in patients with asthmao Rhinovirus isolated in wheezing infants is the strongest predictor for wheezing after 3rd year of life Pests & petso Dust, house dust mites, furry & feathered pets and endotoxins from gram negative bacteria play a role
ETIOLOGY…….. Obesityo ↑ BMI increases the risk Tobacco smokingo Parental smoking odds ratio 1:21 for asthmao Parental smoking causes high BHR at 1 month of age & lower lung function at 6 years Other causeso Paracetamol usage,Rhinitis
ETIOLOGY- THE HYGEINEHYPOTHESIS Children reared on farms have a lower incidence of asthma. Exposure to allergenic factors since newborn period encourages tolerance to common aeroallergens. The immune system of the newborn is skewed toward TH2 cytokine generation . Over time, environmental stimuli activate TH1 responses and bring the TH1/TH2 relationship to an appropriate balance. Anderson WJ, Watson L. Asthma and the hygiene hypothesis. N Engl J Med. May 24 2001;344(21):1643-4.
PATHOPHYSIOLOGY Interactions between environmental and genetic factors result in airway inflammation Airway inflammation → loss of normal balance between two "opposing" populations of T helper (Th) lymphocytes. Th1 → IL-2 and IFN-α → help cellular defense. Th2 → generates cytokines → mediate allergic inflammation.
PATHOPHYSIOLOGY………… Chronic inflammation of the airways → increased BHR → bronchospasm and airway obstruction Airway obstruction → increased resistance to airflow → decreased expiratory flow rates → air trapping and hyperinflation. Hyperinflation → alteration in pulmonary mechanics → increases the work of breathing → ventilation perfusion mismatch
COUGH Cough is an early symptom in childhood asthma which can be overlooked for years if the airway obstruction has not been severe enough to produce wheezing. National guidelines for management of asthma 2007;112
GRADING OF ASTHMASTEP DAY SYMPTOMS NIGHT FEV1 & PEF SYMPTOMSMILD ≤ 2times/week ≤ 2times/month FEV1 or PEF<80%INTERMITTENT PEF variability <20%MILD > 2times/week >2times/month FEV1 or PEF<80%PERSISTENT Less than 1time/day More than PEF variability 20- 2times/mo 30%MODERATE 1 time/day > 1 time/week FEV1 or PEF 60-80%PERSISTENT PEF variability >30%SEVERE continuous frequent FEV1 or PEF <60%PERSISTENT PEF variability >30%
DIAGNOSIS Primarily clinical Look for key features Consideration & exclusion of alternative diagnoses Expect improvement with bronchodilators If management ineffective -Question the diagnosis Objective tests are difficult to perform
OBJECTIVE TESTS Possible in children over 5 years Variability of Peak expiratory flow (PEF) and Forced expiratory volume in first second (FEV1) Percentage variability=(highest-lowest) × 100 highest
OBJECTIVE TESTS SPIROMETER PEAKFLOW METER
OBJECTIVE TESTS PEFo Low than predictedo 20 % change after bronchodilator or exercise FEV1o Low than predictedo Improvement by ≥ 12% after bronchodilatoro Worsening by ≥ 15% after exerciseo AM to PM variation ≥ 20%o FEV1/FVC < 0.8
OTHER INVESTIGATIONS CXRo During initial diagnosiso Severe life threatening episode HYPERSENSITIVITY TESTSo RAST & allergic skin testso Not available in SLo Trigger factor to be detected
MANAGEMENTGoals of Management Minimal or no symptoms Minimal or no exacerbation Minimal or no need of relievers FEV1 or PEF over 80% of predicted Minimal or no adverse effects from medications Normal activities and rare school absences Optimum growth Minimal effect on family members
NON PHARMACOLOGICALMANAGEMENTPrimary prevention Breast feeding Exposure to allergens/infections at early age Avoiding maternal smokingNo clear benefits with…… Avoidance of postnatal exposure Modified infant formula Vit C , fish oil Journal of Paediatrics 2001;139:261-6 Journal of Tropical Paediatrics 2001;47:142-5
NON PHARMACOLOGICAL MANAGEMENT…………. Secondary prevention Avoid identified allergens Avoid smoking, air pollution ObesityNo clear benefits with…….. Alternative medicine Generalized dietary restrictions Goats milk New England J medicine 1990;323:502-7 Clin Exp allergy 1999;29;905-11
PHARMACOLOGICALMANAGEMENT Long term management Management of an acute exacerbation
STEPWISE LONG TERMMANAGEMENT STEPS DAILY MEDICATION MILD INTERMITTENT No daily medication MILD PERSISTENT •Low dose inhaled steroids •Sustained release theophylline •Leukotriene receptor antagonists •Ketotifen MODERATE PERSISTENT •Medium dose inhaled steroids OR Low dose inhaled steroids + long acting ß2 agonists SEVERE PERSISTENT •High dose inhaled steroids + long acting ß2 agonists •May need oral steroids
STEPWISE LONG TERMMANAGEMENT Step down theory Step up theory Referring steps
INHALER DEVICES < 2 years -MDI + Baby haler 2-3years -MDI + Spacer device + face mask 3-5 years- MDI + Spacer device 5-8 years -MDI + Spacer device or DPI > 8 years- MDI or DPI
EVIDENCE BASED PRACTICE Combination inhalers- steroid and long acting beta agonists The new inhaled steroids - CICLESONIDE and MOMETASONE FUROATE The extra fine HYDROFLUOROALKANE BECLOMEHASONE Leukotiriene antagonists- MONTELUKAST Mononoclonal antibodies against IgE - OMALIZUMAB Immunotherapy Perera B J C .Paediatric respirology 2010 Perera B J C.Modern reinements in prophylaxis of wheezing 2011
MANAGEMENT OF SEVERE ATTACK Observe in the acute side/HDU High flow oxygen Nebulise with Salbutamol• every 15 mins or continuous Nebulise with Ipratropium• initially every 20 mins, then 6 hourly If no response exclude pneumothorax, heart failure Steroids• effects appear after 4 hours
MANAGEMENT OF SEVERE ATTACK….. If deteriorating, exhausted or confused admit to ICU IV Fluids to correct hydration IV Aminophyllineo bolus 5-10 mg/kg if was not on theophylline within 24 hours, maintenance 1mg/kg/hro can cause arrythmia, seizures, vomiting IV Salbutamolo bolus 5µg/kg over 10 mins, maintenance 0.5-1µg/kg/mino can cause hypokalemia
MANAGEMENT OF SEVEREATTACK….. IV Magnesium sulphateo Bolus 40-100 mg/kg for 20mins,maintenance 30mg/kg/hro Causes arrythmia, hypotension, vomiting Indications for mechanical ventilationo Worsening life threatening asthmao Severe exhaustiono Impending respiratory failureo PCO2>60mmHg, PO2<50mmHgo Worsening metabolic acidosis
EVIDENCE BASED PRACTICE In acute asthma MDI+spacer is equally effective as nebulisers. Addition of inhaled anti-cholinergics to beta agonists has proven benefit IV Aminophylline is useful than IV Salbutamol The place of IV Magnesium Sulphate is still not well established, but several studies show it to be beneficial. Perera B J C .Paediatric respirology 2010 Perera B J C.Modern reinements in prophylaxis of wheezing 2011
SUMMARY Asthma is a Multifactorial disease Correct diagnosis is the cornerstone in management Choosing the best drug combination, best mode of administration and correct technique will reduce the morbidity. Death due to Asthma is definitely preventable with the timely diagnosis and management of the life threatening episode