Asthma and Airway Emergencies: Assessment, Analysis, and Associated Dental Management Guidelines
Asthma is a condition that is a consequence of an immune response. The airways become sensitive to allergens causing bronchial hyper-responsiveness and narrowing. Increased inflammation and increased mucus production during an asthma attack causes further narrowing of the airways. Wheezing, coughing, shortness of breath, chest tightness, and increased respiratory rate are the hallmark features of asthma. Patients with allergies and eczema have a higher predilection for asthma. IgE is produced in excess in these patients and IgE blocks the β2 receptors, causing asthma.
Allergy-associated asthma is labeled as extrinsic asthma. This type of asthma is more common in childhood and improves with age or disappears completely in adulthood. Extrinsic asthma can persist in adulthood, but it rarely progresses to COPD. COPD is less often associated with familial allergies or eczema and is more often associated with intrinsic asthma and smoking.
Intrinsic asthma occurs in adulthood and it is often triggered by pulmonary infections. Intrinsic asthma often leads to COPD, and compared to asthma, COPD, in general, is less responsive to brochodilators.
Asthma Symptoms and Signs
Patients are usually symptomatic with asthma at night or during the early morning hours, but an anxious patient can have an asthma attack at any time when faced with stressful situations that act as triggers for the attack. During an asthma attack the respiratory rate is increased, the expiration is prolonged, and the patient experiences tachycardia. Ronchi and wheezing are primarily heard on expiration initially, but with progressive worsening of the asthma, the ronchi and wheezing can be heard by auscultation in both the inspiration and expiration phases. The patient uses the accessory muscles of respiration and the sternocleidomastoid and scalene muscles of the neck to assist with the breathing and oxygenation. Asthma is also associated with a paradoxical pulse, wherein the pulse increases during expiration and decreases during inspiration.
Asthma can be intermittent or it can result in chronic respiratory impairment. The range of severity of asthma is determined by the frequency of asthma attacks and the number of attacks that occur at night or in the early hours of the morning.
Asthma Classification per the US National Heart, Lung, and Blood Institute
The four categories of asthma identified by the US National Heart, Lung, and Blood Institute (NHLBI) are mild intermittent, mild persistent, moderate persistent, and severe persistent. A severe asthma attack is a true emergency needing immediate attention because it can be associated with near closure of the airways and decreased oxygen supply to the vital organs. This is of particular concern in the patient with severe persistent asthma where the FEV1 is <60%.
Asthma Etiological Factors
Common etiological factors causing asthma are:
- Viral infections, which are the leading cause for asthma attacks in children.
- Irritants, such as cigarette smoke and cold air.
- Allergens, such as dust and pollen.
- Medications, such as β-blockers, aspirin, sulfites, penicillin, glaucoma medications, and NSAIDS.
Asthmatic patients often have allergies, and allergy-associated asthma most often begins in childhood.
Diagnosis of asthma is made as follows:
The goal of asthma management should be such that the patient has good exercise capacity, has fewer attacks, and is less dependent on immediate-relief drugs, as much as possible. Asthma management is best achieved by:
- Elimination of the precipitating factors where possible, especially with allergens.
- Implementation of care by the patient immediately on recognizing the signs and symptoms of asthma.
The medications for the management of asthma can be categorized as:
- Immediate-relief medications.
- Medications for long-term control and prevention of asthma attacks.
- Asthma emergency treatment drugs.
Short-acting, inhaled β2 agonist bronchodilators (metaproterenol, albuterol, terbutaline, and pirbutrol) are the preferred quick-relief medications that open up the airways and bring relief within minutes of using the inhaler.
Patients should always carry their bronchodilator with them and use it immediately when becoming symptomatic. An early addition of corticosteroid inhalants with the β2 agonist can often show an arrest in the progression of asthma.
Occasionally, the β2 agonist bronchodilators can cause an increased heart rate or an increased BP at higher doses. When this happens, ipratropium bromide, an anticholinergic medication, can be used instead because the drug has no cardiac side effects. The disadvantage, however, is that ipratropium bromide is not immediate in action and is not as effective as the β2 agonist.
Medications for Long-Term Control and Prevention of Asthma Attacks
Medications for long-term control and prevention of asthma are taken daily (Table 31.1). To become optimally effective they need to be taken for weeks. Be aware that the long-acting inhalers are slow in action, so the short-acting inhalers may have to be used during an asthma attack.