a chronic inflammatory disorder of the airways in which many cells, including mast cells and eosinophils, play a part. The inflammation causes symptoms associated with obstructive airflow and characterized by recurring attacks of paroxysmal dyspnea, wheezing, prolonged expiration, and an irritative cough that is a common, chronic illness in childhood. Onset usually occurs between 3 and 8 years of age. Asthmatic attacks are caused by constriction of the large and small airways, resulting from bronchial smooth muscle spasm, edema or inflammation of the bronchial wall, or excessive production of mucus. It is a complex disorder involving biochemical, immunological, infectious, endocrinological, and psychological factors. Asthma attacks in the past were classified as either extrinsic or intrinsic. Most extrinsic attacks in children were associated with an allergenic hypersensitivity to a foreign substance, such as airborne pollen, mold, house dust, certain foods, animal hair and skin, feathers, insects, smoke, and various chemicals or drugs. In infants, especially those with a family history of allergic reactions, food allergy is a common precipitating factor. Intrinsic attacks were associated with physical stress resulting from fatigue or exercise, exposure to cold air, or psychological stress; this system of classification has been abandoned because many of the triggering factors overlap.
observations Asthma in children is often confused with acute middle and lower respiratory tract infections, congenital stridor, obstruction of the bronchi or trachea, bronchial or tracheal compression, and cystic fibrosis. The diagnosis is generally determined by observation during a physical examination, medical history, and familial allergic disease. Laboratory tests and x-ray studies may eliminate identification of other diseases. A diagnostic feature is the presence of large numbers of eosinophils and Charcot-Leyden crystals in the sputum. Pulmonary function tests are valuable for assessing the degree of airway obstruction and the volume of gas exchange. Asthmatic episodes vary greatly in frequency, duration, and degree of symptoms. They may range from occasional periods of wheezing, mild coughing, and slight dyspnea to severe attacks that can lead to total airway obstruction and respiratory tract failure (status asthmaticus). An attack may begin gradually or abruptly and is often preceded by an upper respiratory infection. Typically an attack begins with signs of air hunger; yawning; sighing; shortness of breath; paroxysms of wheezing; and a hacking, nonproductive cough. As secretions increase, the expiratory phase becomes prolonged. A large quantity of thick, tenacious mucoid sputum is produced as the attack subsides. The child appears apprehensive, speaks in a panting manner, and may assume a bent-over position to facilitate breathing. The prolonged expiratory phase is not as noticeable in infants and young children. In severe spasm or obstruction the respirations become shallow and irregular. A sudden increase in the rate of respiration, repeated hacking, and nonproductive coughing are indicative of lack of air movement with impending ventilatory failure and asphyxia.
interventions Management of asthma in children is based on four stages of severity: intermittent, mild persistent, moderate persistent, and severe persistent. Clinical features of intermittent asthma include symptoms that occur less than once a week, brief exacerbations from a few hours to a few days, nighttime episodes that occur less than twice a month, and normal lung function between exacerbations. Mild persistent classification is characterized by symptoms that occur more than once a week but less than once a day and nighttime episodes that occur more often than twice a month. Moderate persistent severity is manifested by daily symptoms with exacerbations that affect daily activities and sleep. Severe persistent asthma is characterized by continuous symptoms that limit physical activities, frequent exacerbations, and nighttime symptoms. Medications are classified as relievers and controllers to relieve symptoms immediately. A reliever may be a short-acting medication, such as a beta2 agonist that serves as symptomatic therapy. Controllers such as inhaled and systemic corticosteroids and sustained-release theophylline are prescribed on a regular basis to keep symptoms under control. In the long-term management of asthma in children, an effort is made to control the symptoms with the minimum amount of medication, increasing the number and frequency of medications as symptoms increase and reducing the level as symptoms are brought under control. The major drugs used to relieve bronchospasm are the beta-adrenergic agents, including the relievers isoproterenol, metaproterenol, terbutaline, and salbutamol; the methylxanthines, including theophylline and aminophylline; corticosteroids; expectorants; and antibiotics for cases in which infection is the triggering mechanism. Rarely an acute attack does not respond to any of these measures, resulting in status asthmaticus. Hospitalization is required. The child is usually in a state of dehydration and acidosis with hypoxia and hypercapnia. Management consists of administration of IV fluids; humidified oxygen given by mask or cannula; administration of sodium bicarbonate or tromethamine to keep pH at acceptable levels; and use of bronchodilators to alleviate bronchospasm and of antibiotics to reduce risk of infection. Mild, intermittent episodes of asthma are treated with bronchodilators in aerosol sprays, which provide quick relief and are effective in controlling an attack; oral administration is preferred for younger children. Those with persistent chronic asthma receive daily oral doses of a bronchodilator, often theophylline, usually in combination with an expectorant and corticosteroids. Bronchospasm induced by exercise can be treated prophylactically with cromolyn sodium, a controller that inhibits the release of histamine in the lungs. Long-range management and treatment include physical training and exercises to induce physical and mental relaxation, improve posture, strengthen respiratory musculature, and develop better breathing patterns. Hyposensitization is recommended when an allergen is known and cannot be avoided. Prognosis varies considerably; many children lose their symptoms at puberty but the symptoms reappear in their 40s. The prognosis depends on the number and severity of symptoms, emotional factors, and the family history of allergy.
nursing considerations The primary focus of nursing care for children with acute asthma is to relieve symptoms of respiratory distress by initiating IV infusion and oxygen therapy, correcting acidosis, and administering bronchodilators and corticosteroids. The nurse implements measures to promote physical comfort, induce rest, and reduce fatigue and anxiety. An especially important role is reassuring the child and parents about procedures, equipment, and prognosis. The nurse also plays a significant role in the long-term support of children with chronic asthma, primarily in teaching the child and parents about the disease and how to cope with the condition. Once an allergen is determined, the home environment must be modified to reduce or eliminate contact with possible causative agents, including presence of warm-blooded pets, tobacco smoke, cockroaches, dust mites, and fungi. The nurse teaches the child and parents how to use prescribed medications, especially nebulizers and aerosol devices, how to detect early signs of an attack so that it can be controlled with medication, how to determine any adverse effects of the drugs, especially the dangers of overuse, and how to implement physical exercise and play activities as therapeutic measures, especially those that promote proper breathing techniques. Further educational support for families of children with asthma may be obtained from organizations such as the Asthma and Allergy Foundation of America and the American Lung Association.