CHILDHOOD ASTHMA DR WANG MAY KAY PAEDIATRIC DEPARTMENT HOSPITAL SELAYANG ASTHMA 3 hallmarks: •reversible airway obstruction •airway inflammation •airway hyperresponsiveness Clinical manifestation of asthma derive primarily from airway obstruction What is the cause of asthma? The inflammation is produced by allergy, viral respiratory infections and airborne irritants. Allergic reactions produce both immediate and late phase (delayed) reactions. This late phase reaction produces more serious injury and airway inflammation irritability or hyperresponsive airway. Prolonged airway inflammation can cause scarring. Anatomy of the bronchioles and alveoli Narrowed and inflammed bronchial tube in acute asthma Pathophysiology of asthma Environmental factors Genetic predisposition Bronchial inflammation Bronchial hyperactivity + trigger factors Oedema Bronchoconstriction Mucus production Airway narrowing Symptoms Signs and Symptoms in children •Wheeze •Nocturnal cough •Exercise induced cough •Chest tightness and SOB •In a young child, the discomfort of chest tightness may lead to unexplained irritability . •Child with frequent cough / respiratory infections ( pneumonia / bronchitis) should be evaluated for asthma. Signs and symptoms in children • 33% of children have eczema • 50% have allergic rhinitis + conjunctivitis • Asthma presents as recurrent wheeze, breathlessness, cough • Chronic asthma – chest hyperinflation, pectus carinatum ( piegon chest) , • Harrison’s sulci ( permanent groove in the chest wall at insertion of diaphragm) Triggering factors •Exercise •Infections •Allergy •Irritants •Weather •Emotions Exercise • running can trigger an episode in >80% of children with asthma • bronchodilator medications used before exercise can prevent most of these episodes. Exceptions: prolonged running especially during cold weather, allergy season or illness from a “cold” • Swimming is the least asthma - provoking form of exercise. Infections • Respiratory infections usually trigger severe episodes of asthma • Bronchodilator medication, good hydration and corticosteroids are required to control an asthma episode triggered by viral infections. • Chronic sinusitis , ear infection and bronchitis can trigger asthma and this would require antibiotic therapy. . Allergy •during an allergic reaction, chemical mediators are released.This produces mucosal swelling, excessive mucus secretion and muscle contraction in the airways. Thus an allergy can provoke an asthma episode. •Allergens (house dust, feathers, pollens, milk,soy, egg etc) •These allergens may produce low - grade reactions which are of no obvious consequence; however , daily exposure to these allergens may result in a gradual worsening of asthma Useful measures to reduce exposure to house dust mite • install zippered plastic or vinyl covers • pillows should be encased in plastic or laundered once a month • fluffy stuffed animals and soft furnishings should be removed • carpets should be removed from bedrooms • all bedding should be laundered frequently • air conditioning is helpful to lower the relative humidity if patient is allergic to mites or pollen • vacuuming will remove < 10% of mites Irritants • Cigarette smoke, air pollution, strong odour, aerosol spray and paint fumes irritate the tissues of the lungs and upper airways. • The reaction (cough, wheeze, runny nose and watery eyes) produced by these irritants can be identical to those produced by allergens. • Cigarette smoke is highly irritating and can trigger asthma. • Irritants must be recognised and avoided. Weather • Cold air can trigger asthma • precaution is necessary to avoid inhalation of cold air. • A heavy scarf , worn loosely over the nose and mouth , will help to avoid cold air induced asthma. • The weather affects outdoor inhalant agents ( pollens ) . On a windy day more allergens will be scattered in the air, while a heavy rainfall will wash the air clean of allergens. Emotions •emotional stress (anxiety, frustration, anger) can trigger asthma •emotional responses involve deep rapid breathing which in turn can trigger asthma •children with asthma can suffer from severe anxiety during an episode of suffocation produced by asthma.This can produce hyperventilation , which further triggers asthma. •. Assessment of severity in childhood asthma Mild (Infrequent episodic) Episodes at least 4-8 weeks apart Episodes generally not major No interval symptoms apart from exercise induced No abnormal signs and normal lung function between episodes Moderate (Frequent episodic) Severe (Persistent) Episodes < 4-8 weeks Apart Episodes more troublesome More interval symptoms Symptoms many to most days or nights Acute episodes < 4-8 weeks apart Daily or near daily use of B2 agonist No abnormal signs and normal to near normal lung function in between episodes Abnormal lung function on “average” day Assessment of severity of acute asthma Mild(unlikely to need admission) No Altered consciousness Physical exhaustion No Moderate(may need admission) No Severe(needs admission) Yes No Yes Talks in Sentences Phrases Words Pulsus paradoxicus Not palpable May be palpable Palpable Central cyanosis Absent Absent Present Wheeze on auscultation Use of accessory muscles Sternal retraction Present Present Silent chest Absent Moderate Marked Absent Moderate Marked Initial PEF >60% 40-60% <40% Oximetry(SaO2) >93% 91-93% 90% and below Goals of therapy • • • • • • • participation in normal activities minimal chronic symptoms minimal absences from school minimal need for use of beta agonist elimination of necessity for ED visit/warded restoration to and maintenance of normal PEF and minimal adverse effects from medications Patient and parent education • • • • • reaching agreement goals rehearsals repetition reinforcement review Asthma therapy • RELIEVER • PREVENTER / CONTROLLER Types of drugs used in asthma reliever • Beta 2 – agonists – salbutamol (ventolin) • - terbutaline (bricanyl) • Ipratropium bromide (atrovent) Types of drugs used in asthma – preventive drugs • Corticosteroids: • - prednisolone • - beclomethasone diproprionate (becotide) • - budesonide (pulmicort/ inflammide) • - flucatisone propionate (flixotide) • Theophylline • Sodium cromoglycate (intal) • Long acting B 2 agonist – Salmeterol • Combination – salmeterol/ flucatisone • Antileukotrienes – montelukast (singular) Recommendation for different ages Age (yrs) < 8 years > 8 years MDI + MDI + Spacer + Spacer Aerocham ber + + + Dry powder inhaler - + Management Infrequent Episodic ( mild) - intermittent inhaled beta2 agonists Frequent Episodic (moderate) - continue intermittent beta2 agonists - add inhaled sodium cromoglycate Management of Childhood Asthma Con’t Persistent asthma (severe) - replace inhaled sodium cromoglycate with low dose inhaled steroid (<400mcg/day) - continue intermittent inhaled beta2 agonists - if still symptomatic, increase to moderate dose of inhaled steroids (400-800mcg/day) - if still not controlled, consider adding theophyllines or long acting beta2 agonists Management of Childhood Asthma Con’t If the child is still symptomatic, re-evaluate the symptoms and history - increase to high dose of inhaled steroids (800-1200mcg/day) Rationale for prolonged prophylactic therapy • acute bronchodilator therapy unsatisfactory for long term prognosis • need to treat underlying inflammation • reduction of bronchial hyperresponsiveness • prevention of later development of irreversible airflow obstruction Aims of treatment of acute asthma exacerbations • • • • Prevent death relieve airway obstruction relieve hypoxaemia restore patient’s clinical condition and lung function to normal as soon as possible • maintain optimal lung function and prevent early relapse • plan avoidance of future relapses and • develop an action plan in case of further exacerbations. Management of AEBA - prop up + O2 ( via face mask/ nasal prong) --combivent nebuliser ( salbutamol / ipratropium) -nebulised B2 agonist + ipratropium bromide -(salbutamol 0.5:3.5 < 1 year, 1:3 > 1 year) - steroids (oral / IV) : prednisolone 1mg/kg/day : hydrocortisone 4mg/kg/dose Q6H - - continuous observation Management of AEBA • • • • If no response to above, Start IV salbutamol continuous infusion Add IV aminophylline Mechanical ventilation THANK YOU