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). mar 2007 www.pediatricianonline.in GSMC KEMH

www.pediatricianonline.in GSMC KEMH 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 mar 2007 www.pediatricianonline.in GSMC KEMH

www.pediatricianonline.in GSMC KEMH Pathophysiology 2 In the early stages of an acute episode, ventilation-perfusion mismatch => results in hypoxia, No hypercarbia. respiratory alkalosis results from hyperventilation. ======================================= 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. mar 2007 www.pediatricianonline.in GSMC KEMH

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. mar 2007 www.pediatricianonline.in GSMC KEMH

"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. mar 2007 www.pediatricianonline.in GSMC KEMH

genetic background of cytokine imbalance Early asthmatic responses occur via IgE-induced mediator release from mast cells within minutes of exposure and last for 20-30 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. mar 2007 www.pediatricianonline.in GSMC KEMH

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 mar 2007 www.pediatricianonline.in GSMC KEMH

www.pediatricianonline.in GSMC KEMH 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 mar 2007 www.pediatricianonline.in GSMC KEMH

www.pediatricianonline.in GSMC KEMH 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. mar 2007 www.pediatricianonline.in GSMC KEMH

www.pediatricianonline.in GSMC KEMH 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. mar 2007 www.pediatricianonline.in GSMC KEMH

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%. mar 2007 www.pediatricianonline.in GSMC KEMH

www.pediatricianonline.in GSMC KEMH 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%. mar 2007 www.pediatricianonline.in GSMC KEMH

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 FEV1 60-80% of the predicted values, and PEF varies by more than 30%. mar 2007 www.pediatricianonline.in GSMC KEMH

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%. mar 2007 www.pediatricianonline.in GSMC KEMH

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. mar 2007 www.pediatricianonline.in GSMC KEMH

www.pediatricianonline.in GSMC KEMH 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 mar 2007 www.pediatricianonline.in GSMC KEMH

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. mar 2007 www.pediatricianonline.in GSMC KEMH

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 mar 2007 www.pediatricianonline.in GSMC KEMH

Clinical grading of breathlessness Breathless on walking Breathless on talking Breathless at rest Breathless => impending respiratory failure mar 2007 www.pediatricianonline.in GSMC KEMH

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. mar 2007 www.pediatricianonline.in GSMC KEMH

www.pediatricianonline.in GSMC KEMH physical findings Mild Moderate Severe Status Tachypnea + ++ +++ May be arrest Tachycardia Upto 100 100-120 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? mar 2007 www.pediatricianonline.in GSMC KEMH

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. mar 2007 www.pediatricianonline.in GSMC KEMH

www.pediatricianonline.in GSMC KEMH 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 mar 2007 www.pediatricianonline.in GSMC KEMH

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. mar 2007 www.pediatricianonline.in GSMC KEMH

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 mar 2007 www.pediatricianonline.in GSMC KEMH

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. mar 2007 www.pediatricianonline.in GSMC KEMH

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 mar 2007 www.pediatricianonline.in GSMC KEMH

www.pediatricianonline.in GSMC KEMH Inhalation devices mar 2007 www.pediatricianonline.in GSMC KEMH

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www.pediatricianonline.in GSMC KEMH Visit http://www.peditips.com for various pediatric medicine related tips. mar 2007 www.pediatricianonline.in GSMC KEMH