Download Pediatric Asthma

Pediatric Asthma
Asthma is a chronic inflammatory disorder of the airways. It is one of the most common chronic diseases worldwide and is the most common chronic condition and cause of hospitalization for children in the United States. Despite recent advances in understanding of the pathophysiology and treatment of asthma, the condition continues to have significant medical and economic impacts worldwide. According to the American Lung Association 22.9 million Americans had asthma in 2006. The most recent data shows that 8.4 million children between the ages of 5‐17 had asthma. In children, the rate for boys is 46% higher than among girls. The morbidity of asthma is significant. Every day in the US; 40,000 people miss school or work due to asthma, 30,000 people have an asthma attack, 5,000 people visit the emergency room, 1,000 people are admitted to the hospital (nearly half of these are children), and 11 people die from asthma. In New Mexico, 7.5% of children <17yrs currently have asthma. The pathophysiology of asthma involves several components including airway inflammation, intermittent airflow obstruction and bronchial hyperresponsiveness. Additionally, airway edema and mucus hypersecretion contribute to airflow obstruction. Inflammation in asthma may be acute, subacute, or chronic and results in bronchial hyper responsiveness. Airway hyper responsiveness in asthma is an exaggerated response to endogenous and exogenous stimuli (triggers) and typically correlates to the clinical severity of asthma. The result is obstructed and narrowed airways which manifests clinically as recurrent episodes of cough, chest tightness, shortness of breath and wheezing A careful history is the single most important element in evaluation of child suspected of having asthma. Special attention should be given as to whether symptoms are attributable to asthma, whether findings support the likelihood of asthma, asthma severity and identifying possible triggers and or aggravating factors. It is important to remember that symptoms can follow varying patterns (e.g. perennial vs. seasonal, episodic vs. continual, diurnal variations etc.). Common triggers include irritants (cigarette smoke, air pollution), climate/season changes, viral URI, exercise, inhaled allergens, and emotional stress. Aggravating factors may include allergic rhinitis and or postnasal drip, GERD, obesity, sleep apnea etc. The diagnosis of asthma in childhood is essentially a clinical one. Any child with recurrent episodes of wheezing should be considered as having asthma until proven otherwise. The diagnosis of asthma is even more likely if the symptoms are episodic, associated with a “trigger” and respond to anti‐asthmatic medications. It is also important to remember that ~ 5% of children with asthma present with a persistent or recurrent cough as the sole symptom. The cough is typically dry, worse at night and aggravated by exercise, allergen exposure and viral infections. In addition, exercise induced asthma occurs in the majority of patients with asthma and, is particularly troublesome in children because of their high level of physical activity Physical examination is usually normal. CXR is frequently normal although a history of persistent/ recurrent pneumonia on CXR is not unusual and represents atelectasis from mucus plugging of peripheral airways. Pulmonary function testing (spirometry) can be used to support the diagnosis of asthma. If airway obstruction is present, the diagnosis can be confirmed by demonstrating an improvement in FEV1 by at least 12% following administration of a short acting bronchodilator. In those with normal PFT and atypical clinical history, bronchial provocation testing (methacholine/histamine, cold air or exercise) to demonstrate airway hyper responsiveness can be helpful. Atopy is present in majority of asthmatics and does correlate with airway hyper responsiveness; therefore allergy testing for environmental allergens can be useful. This will allow parents to practice avoidance measures when possible The old adage “all that wheezes is not asthma” still applies today. History and physical examination should focus on excluding other potential causes for recurrent wheezing, especially in the younger child. Clinical features suggesting alternate diagnosis include wheeze associated with feeding, choking with feeds, and the sudden onset of choking/cough, recurrent infections, stridor or steatorrhea. Physical findings suggesting alternate diagnosis include failure to thrive, clubbing, cardiac murmur or unilateral signs. Further testing, such as: CXR, sweat test, barium swallow, immunology workup etc may then be necessary The long‐term outpatient management and control of asthma should follow the stepwise therapy model based on the National Heart Lung and Blood Institute (NHLBI) Guidelines for the Diagnosis and Treatment of Asthma (http://www.nhlbi.nih.gov/guidelines/asthma/index.htm). These guidelines, initially issued in 1991, were revised last year. The essential components of asthma care include: assessment and monitoring, patient education, control of factors contributing to asthma severity along with pharmacologic treatment. The expert panel recommends the stepwise approach to therapy, specifying treatment for three age groups: 0‐4 years, 5‐11 years, and 12 years and older. Goals of therapy are to maintain long term control by reducing troublesome symptoms and exacerbations, maintain normal (or near) normal pulmonary function and activity levels and to meet families expectations of and satisfaction with asthma care. Control should be achieved with minimal amount of medication so as to avoid adverse effects Medications used for asthma are generally divided into 2 categories, quick relief (also called reliever medications) and long‐term control (also called controller medications). Quick relief medications are used to relieve acute asthma exacerbations and to prevent EIA symptoms. These medications include short‐acting beta‐agonists, anticholinergics (used for severe exacerbations), and systemic corticosteroids, which speed recovery from acute exacerbations. Long‐term control medications for children are primarily inhaled corticosteroids. Long‐acting beta‐agonists (including combination therapy with inhaled corticosteroids), methylxanthines, and leukotriene antagonists, are added in step wise approach when patient demonstrates ongoing poor control despite being on inhaled corticosteroids at moderate dosages. The major cause of poor asthma control or lack of response to asthma medication is compliance, which also includes incorrect use of devices. At all follow up visits time should spent going over medications, parents understanding of and use of medications along with enquiry as to side effects and parents/patients overall level of happiness with asthma control and therapies. The natural history of asthma is not well described. For most infants/children, wheezing before the age of six years is most likely a benign condition reflecting smaller airways that will improve or resolve by 5‐6 years of age. A subgroup, characterized by atopy, relatively severe and persistent symptoms in first year of life, maternal asthma and maternal smoking, will have persistence of symptoms and eventually develop clinical asthma. Between 30‐70% of children who develop asthma are markedly improved or asymptomatic by early adulthood. The pattern of asthma during childhood also appears to predict the progression of disease decades later. Those with mild disease are unlikely to develop severe disease and those with severe symptoms have lower lung function and this persists into adult life. Evidence to date does not support the view that inhaled corticosteroids alter the natural history of asthma; rather they are used to control asthma symptoms and improve child’s quality of life.