Asthma is the most common chronic condition of childhood and the most common cause of chronic illness that limits childhood physical activity. When uncontrolled, asthma can meaningfully limit daily life, and asthma is an occasional cause of death. Discussion
Status asthmaticus is a medical emergency where asthma symptoms are not responsive to early treatment with a bronchodilator. Patients may present with acute deterioration with chest tightness, shortness of breath, dry cough, and wheezing. Typically, they present within a few days after the onset of a viral respiratory infection or after exercise in an ambient cold environment with significant exposure to allergens and irritants but may also present with acute onset of symptoms and an undetermined etiology. Early recognition and management is believed to be critical before complications become detrimental and lead to potentially fatal complications such as respiratory failure. Aggressive treatment with beta-agonists, anticholinergics, and corticosteroids remains the gold standard for the disease in question. Asthma is the most common chronic disease of childhood and the leading cause of childhood morbidity from chronic disease, as measured by school absenteeism, emergency department visits, and hospitalizations. Diagnosis and Management of Asthma defines asthma as a common chronic disorder of the airways that is complex and characterized by recurrent and recurrent symptoms, airflow obstruction, bronchial hyper-responsiveness, and underlying inflammation. These features of asthma determine the clinical manifestations, disease severity, and response to treatment. Status asthmaticus is the clinical syndrome characterized by progressively worsening bronchospasm and respiratory failure due to asthma, unresponsive to conventional treatment, and potentially leading to respiratory failure that may require mechanical ventilation or death. Patients are admitted to the hospital for evaluation and management but their initial care should begin in the community before transfer.
Epidemiology
Asthma is the primary cause of admissions to hospitals in the United States, particularly for persons younger than 18 years of age. The number of people diagnosed with asthma has currently increased to 2.2 million in Australia; 14–16% of these are children. Asthma is also more common among Aboriginal Australians. Deaths are also more common among residents of less well-off regions within Australia. Onset of asthma during childhood is common, although onset tends to occur much earlier in males than females. Asthma is rarely the cause of death in children. The most important risk factor would be a delay in presentation in an individual who already has documented severe episodes of asthma. Occasionally the condition may be worse than reported or treatment may intensify over time.
Pathophysiology
Asthma is an inflammatory disease of the airways. It is a disease state characterized by reversible, diffuse lower airway obstruction brought on by diffuse and diffuse airway inflammation and edema, bronchial smooth muscle spasm and mucus plugging. Young children are primarily affected by status asthmaticus. Such triggers as viral infections, allergies, weather changes, exposure to cigarette smoke or other inhaled irritants, gastro-oesophageal reflux, exercise and cold air may sensitize the child's hyper-reactive airway to acute obstruction. Products may cause hyper-reactive airways. Nevertheless, in individuals who are not allergic to aspirin or nonsteroidal anti-inflammatory drugs, ibuprofen exposure does not appear to adversely affect asthma morbidity but may also reduce outpatient visits. Risk factors
It is very difficult to identify at-risk children who are at risk for experiencing fatal asthma attacks. However, one third of children who die due to asthma had illness that was previously reported as mild. Robertson et al14 reported that in an Australian study of the causes of asthma deaths, among 51 deaths, patients had only 39% of cases with potentially preventable factors: of those, 68% had suboptimal assessment of, or treatment for, antecedent asthma; 53% had noncompliance with treatment; and 47% had a delay in presentation. Most, 36%, were scored for severe asthma, 43% had routinely treated with inhaled blexamethasone or sodium cromoglycate, and 10% were routinely treated with oral steroids. Twenty-two percent had a previous admission to the intensive care unit. Patients at high risk of asthma-related death require close observation and should be encouraged to seek medical attention early in acute exacerbations.
Clinical presentation and assessment
Most children with an acute exacerbation of asthma will present with a cough, wheeze, dyspnea, and increased work of breathing (eg. tachypnea, intercostal recession, subcostal retraction). The severity of wheezes does not correlate well with the severity of the disease. The absence of breath sounds - 'silent chest' - may be a sign of respiratory failure in the face of increased work of breathing. Some other findings of severe asthma include disorientation, inability to voice, deeply decreased or absent breath sounds, and central cyanosis.
The history for the initial assessment of a child with acute asthma should include previous attacks and other risk factors, as well as assessing severity using the National Asthma Council Australia criteria. The history should be taken when treatment is started. • History of previous medications, particularly oral/inhaled steroids in the past 6 months • History of previous exacerbations including emergency room, hospitalisation, and intensive care unit admissions • Perception of severity • Associated symptoms and triggers for exacerbations • Current medications including dose, route, and when last given • History of doses missed due to non- or unadministered regimens. Other conditions may be involved in the diagnosis, for example an inhaled foreign body or structural anomalies should also be taken into account where a child is not clearly improving with typical treatments. The assessment in an acute attack basically rests on the diagnostic methods above. Although there are some instances where additional investigations using more definitive tests are considered appropriate and this will never become a routine, treatment should never wait for these procedures. • Chest radiography-This should be performed as an ancillary investigation rather than a routine examination unless pneumothorax or pneumonia is suspected, if the patient is to be intubated, or if other conditions that cause wheezing are suspected. • Degree of impairment of pulmonary gas exchange in critically ill children. They are only performed in children over 6 years of age.
Treatment The aim of treatment in status asthmaticus is reversal of bronchoconstriction, management of airway inflammation, correction of hypoxaemia and monitoring for complications. Oxygen All asthmatic patients suffer from a ventilation/perfusion mismatch and evidence of hypoxaemia should always be dealt with promptly. Oxygen supplements should therefore be administered until an oxygen saturation of greater than 94% is achieved. Bronchodilator therapy
Bronchodilator therapy was used to treat the disease by bronchodilator therapy. Beta-agonists are prescribed as the first prescription for asthmatics, as these cause relaxation of smooth muscle. The first dose of a beta-agonist may be given using an oxygen-powered nebuliser, when hypoxaemia predominates, or via a pressurised metered dose inhaler (MDI) with spacer, by mask or mouthpiece. The efficacy of an MDI plus spacer seems to be higher at higher doses than with a nebuliser in all children. Salbutamol is usually prescribed as a short-acting beta-agonist. Other preparations that are available include terbutaline. In the case of asthma, these are inappropriate. Intravenous beta-agonists should be given to patients who fail with continuous nebulization and to patients for whom nebulization is impossible, for example, intubated patients or any patient whose air entrapment is poor. The side effects of these drugs are tachycardia, arrhythmia, hypertension or hypotension, and hypokalemia. However, there is no such risk of cardiac toxicity. Therapeutic dose: • 6 puffs MDI by spacer (children less than 6 years) = 2.5 mg salbutamol • 12 puffs MDI by spacer (children 6 years or older) = 5 mg salbutamol These doses should be repeated every 20 minutes for three doses in the first hour. If the patient experiences improvement but requires salbutamol once again after 3-4 hours, additional doses are given. If the child requires frequent salbutamol, admit him to hospital. If the child has severe asthma, give continuous nebulised salbutamol with high-flow oxygen and organise urgent transfer to hospital. Anticholinergics 'Usually this class of drugs is given via an inhalation route, but ipratropium bromide is the most common. There are research findings showing that supplementing inhaled ipratropium bromide, for example, Atrovent, with a beta-agonist gives better outcomes with fewer hospital admissions for mild to severe asthma. Child under 6 years • 4–8 inhalations for children 6 years or older. The dose is given Q20min as needed up to three times in the initial hour, followed by Q4–6hrs as required.
Steroids Steroids form an integral component of the first line management of acute asthma. They induce changes in the inflammatory response that lead to reduced inflammation within the airways, repair of the epithelium, reduction in mucus secretion, and down regulation of pro-inflammatory cytokines production. Oral and parenteral steroids are effective; however, parenteral steroids are considered best for very sick children and for children who present with vomiting. Administration of steroids is most effective when given early in the exacerbation. Suitable doses of steroids are: • Prednisolone 1-2 mg/kg per day for 3-5 days is often sufficient. • Every 1 hour initially. If these drugs are not available, use another systemic steroid of a similar dose, eg. hydrocortisone 2-4 mg/kg. Magnesium sulfate The mechanism of action of magnesium sulfate (MGSO4) is believed to be smooth muscle relaxation by inhibition of calcium uptake. Magnesium sulfate may prolong hospitalization in children with severe asthma when added to bronchodilators and steroids. Intravenous MGSO4 is preferred. Methylxanthines Theophylline has two distinct actions on the asthmatic airways: it relaxes smooth muscle, and it stimulates airway sensitivity. Theophylline has a relatively narrow therapeutic index. Aminophylline (the IV formulation of theophylline) is not indicated for asthma in children, except in hospitalized children with very severe asthma. Newer agents, such as leukotriene inhibitors, cannot yet be determined whether they have any role in severe asthmatic episodes. Indications for hospitalisation' Any of the following are indications for hospital admission. • There is no response to three doses of a short acting beta-agonist within 1-2 hours. • The child is unable to speak or drink or is breathless. Intubation and mechanical ventilation Intubation in a patient with an acute severe attack of asthma should be performed at minimal facilities. This may risk the chance for barotrauma. It may also cause worsening of bronchoconstriction due to intubation. Absolute indications for intubation are a cardiopulmonary arrest, severe hypoxia, acute deterioration of the child's consciousness. If intubation is considered necessary, ketamine should be the induction agent due to its bronchodilatory action. Conclusion It is very prevalent within the developing countries and is associated with very severe morbidity in children as well as more developed ones. An at-risk child may not be easily identified. Hence first diagnosis and then initiation of treatment becomes the factor in preventing such threatening complications like failure within the respiratory system. Beta-agonist anticholinergics and corticosteroids as aggressive treatments remain the only strongholds for this type of condition.
