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Chronic, reversible inflammatory airway disease characterized by recurrent attacks of breathlessness and wheezing
Four major classifications of asthma severity used primarily to initiate therapy 1,2:
Affects 5-10% of population
One of the most common chronic diseases of childhood, affecting 7 million children
In children, more common in boys than girls
In adults, more common in women than men, African Americans than Caucasians
Airway inflammation begins with inflammatory cell infiltration, sub-basement fibrosis, mucus hypersecretion, epithelial injury, smooth muscle hypertrophy, angiogenesis that then leads to intermittent airflow obstruction, and bronchial hyperresponsiveness.
Remodeling of airways may occur 1.
Inheritable component with complex genetics and environment interaction
A gene-by-environment interaction occurs in which the susceptible host is exposed to environmental factors that are capable of generating immunoglobulin (Ig) E and sensitization occurs.
Host factors: genetic predisposition, gender, race, BMI
Environmental: viral infections, animal and airborne allergens, tobacco smoke, and so on
Exercise, obesity, and emotional stress
Aspirin or NSAIDs hypersensitivity or β-blockers
Food allergies and asthma increased risk for fatal anaphylaxis from those foods
Eliminate or modify exposure to asthma triggers (e.g., allergens, smoking, aspirin, NSAIDs).
Consider allergen immunotherapy.
Treat comorbidities such as allergic rhinitis.
Annual influenza vaccine (inactivated influenza vaccine) for age ≪6 months
Patients at risk for anaphylaxis should carry an EpiPen.
Atopy: eczema, allergic conjunctivitis, allergic rhinitis
Obesity (associated with higher asthma rates)
Gastroesophageal reflux disease (GERD)
Obstructive sleep apnea (OSA)
Allergic bronchopulmonary aspergillosis (rare)
Question frequency of symptoms and rescue inhaler use.
Symptoms include the following:
May be normal
Blood tests are not required but may find eosinophilia or elevated serum IgE levels.
Spirometry: Normal test does not rule out asthma. It measures the FVC and the FEV1. A reduced predicted ratio of FEV1/FVC with reversibility (increase of 200 mL or 12% of FEV1/FVC) after using a short-acting bronchodilator establishes the diagnosis.
Bronchoprovocation (methacholine, histamine, cold air, or exercise) is used to simulate bronchoconstriction, which is very useful in atypical presentation/normal baseline spirometry. Abnormal test is not entirely specific for asthma, but normal test excludes asthma.
Peak expiratory flow (PEF) rates are inappropriate for diagnosis. Typically used for monitoring of symptoms in diagnosed asthma patients
Chest x-ray is used to exclude alternative diagnoses and to evaluate patients for complicating cardiopulmonary processes.
Allergy skin testing is not useful for diagnosis of asthma but may be considered to evaluate atopic triggers.
Sweat testing in diagnosis of cystic fibrosis
Arterial blood gases are indicated for patients with respiratory distress and hypoxia.
Identify triggers and control exposures.
Identify patients at risk for reactions to aspirin and NSAIDs and avoid exposure.
All patients requiring inhaled agents should be prescribed with spacer (holding chamber) device.
Short-acting β-agonist (SABA) for quick relief of acute symptoms and to prevent exercise-induced bronchospasm 1[A]
Systemic corticosteroids can be used.
Use of holding chambers (“spacers”) improves clinical benefit of inhaled agents and should be prescribed for all.
HFA inhalers provide smaller particle size, better lung deposition, and less oropharyngeal deposition.
All metered-dose inhalers (MDIs) need to be primed before use.
Reserve nebulized delivery of medication for those unable to use spacer (e.g., infants, those intubated).
All short-acting agents are pregnancy Category C.
Inhaled corticosteroids (ICS)
Additional asthma education needed
Comorbidities: rhinitis, GERD, sinusitis, OSA
Specialized testing (e.g., bronchoprovocation, skin testing)
Specialized treatments (e.g., immunotherapy, anti-IgE therapy)
Poorly controlled, moderate to severe persistent asthma in adults
Moderate to persistent asthma in children
Poorly controlled asthma: multiple emergency room visits for asthma
Poorly controlled asthma results in low birth weight, increased prematurity, and perinatal mortality.
Albuterol is the preferred SABA, and budesonide is the preferred ICS due to excellent safety profile 1.
Other ICS agents are pregnancy Category C, but no data indicate their unsafety in pregnancy 1. Montelukast and zafirlukast are Category B but are not studied extensively in pregnancy.
Allergen immunotherapy when clear relationship between symptoms and exposure to an unavoidable allergen
Omalizumab (Xolair): anti-IgE therapy, approved for patients >12 years with moderate to severe asthma
Cochrane Systematic Review found vitamin D supplementation in patients with mild to moderate asthma resulted in decreased exacerbations needing steroid use, ED visits, and asthma admissions 5.
Poor or no response to SABA
PEF or FEV1 ≪40%
Decision for admission should be based on duration and severity of symptoms, severity of airflow obstruction, response to ED treatment, course and severity of prior exacerbations, access to medical care and medication, and adequacy of home condition 1.
Supplemental oxygen to correct hypoxemia
Repeated doses or continuous administration of SABA 1[A]
Ipratropium bromide may be used in the ED but is not for inpatient treatment 1[B].
Systemic corticosteroids for acute exacerbations 1[A].
Adjunctive therapy with MgSO4 or helium-oxygen mixture (heliox) may be considered in severe cases 1[B].
Avoid aggressive hydration in older children and adults.
Careful respiratory monitoring including vital signs, pulse oximetry, response and duration of response to SABA, and when possible, an objective measure of lung function such as PEF or FEV1
Quality-of-life measures: impact on activities, sleep, ED visits/hospitalizations, and so forth
Pharmacotherapy: efficacy, compliance, side effects, technique
Peak flow to evaluate if cough is due to exacerbation in those with known asthma.
Patients' care plan and inhaled medication technique at every visit.
American Academy of Allergy, Asthma & Immunology: 800-822-2762 or http://www.aaaai.org/
American Lung Association: www.lungusa.org
Asthma and Allergy Foundation of America: 800-727-8462 or http://www.aafa.org/
Mattress and pillow covers DO NOT improve outcomes and should not be recommended.
Prognosis is good for male patients, nonsmokers, and children with mild disease.
Asthma worsens in 1/3 of women during pregnancy and improves in another 1/3.
Air leak syndromes: pneumomediastinum, pneumothorax
Medication-specific side effects/adverse effects/interactions
Death: ∽50% of asthma deaths occur in the elderly (age >65 years), and mortality is increasing in that population 6.
J45.909 Unspecified asthma, uncomplicated
J45.901 Unspecified asthma with (acute) exacerbation
J45.20 Mild intermittent asthma, uncomplicated
J45.30 Mild persistent asthma, uncomplicated
J45.902 Unspecified asthma with status asthmaticus
J45.998 Other asthma
493.90 Asthma,unspecified type, unspecified
493.92 Asthma, unspecified type, with (acute) exacerbation
493.00 Extrinsic asthma, unspecified
493.10 Intrinsic asthma, unspecified
493.91 Asthma, unspecified type, with status asthmaticus
195967001 Asthma (disorder)
281239006 Exacerbation of asthma (disorder)
424643009 IgE-mediated allergic asthma (disorder)
266361008 Non-allergic asthma (disorder)
SABA is the most effective rescue therapy for acute asthma symptoms.
Holding chambers should be used by all.
ICSs are the preferred long-term control therapy for patients of all ages.
Peak flow is an inexpensive and easily available monitoring device once the diagnosis of asthma has been established.