CLINICAL ACTIONS:

Asthma is a common lung disorder in which inflammation causes the bronchi to swell and narrow the airways (bronchospasm), causing reversible, recurrent airway obstruction. History and physical are important, not only for making the diagnosis but also to help guide classification which is essential for the management plan. Spirometry should be used in all patients >5 years of age to determine that airway obstruction is at least partially reversible.

History: Key Elements

• Wheezing
• Shortness of breath
• Difficulty breathing
• Chest tightness
• Coughing: Note associated timing
  • At night
  • During exercise
  • When laughing or crying
• Symptoms may interfere with normal activities
• Ask about aggravating environmental factors such as
  • Viral infection
  • Animals with fur or hair
  • Mold
  • Smoking
  • Pollen
  • Menstrual cycle

Physical Exam

• Auscultation: Listen for the following especially when exhaling
  • Wheezing
  • Whistling
• Other clinical findings: Include assessment of the following
  • ENT: Ears, nose, throat for swelling, drainage due to allergy and/or inflammation
  • Chest: Hyper expansion of thorax (especially children)
  • Skin and eyes: Atopic dermatitis | Eczema | Evidence of allergic condition

Pulmonary Function Tests

Spirometry

• Test used for both diagnosis and monitoring
• Normal score: ≥80 % of predicted value
  • Tests the forced expiratory volume of air that can be exhaled during forced breath
    • FEV1 (forced expiratory volume): Volume exhaled in the first second
    • FVC (forced vital capacity): Total volume exhaled after a deep breath
    • FEV1/FVC ratio: When FEV1 <80% of FVC, suspicious for obstructive rather than restrictive lung disease (more likely to decrease proportionally)
    • If FEV1 ≥12% after bronchodilator challenge indicative of reversible airway obstruction 

Fractional Exhaled Nitric Oxide (FeNO)

• FeNO testing measures the nitric oxide, a byproduct of inflammation, in exhaled breath
• May be useful in diagnosing, managing and predicting future exacerbations in some types of asthma
• May be used as an adjunct to the evaluation process

Notes: FEV6 (volume after 6 seconds) can be considered rather than FVC in adults for whom full exhalation may take several seconds and be associated with light headedness | There are contraindications to spirometry (e.g., unstable cardiac disease or recent MI, aneurysms, recent thoracic or abdominal surgery, active viral infection, unexplained hypertension) | pre and post bronchodilator testing may be done in pulmonologist practice

Allergy Testing for precipitating factors  

• Consider referral for allergy testing if possibility that patient has allergies which may precipitate asthma (e.g., cats, dogs, medications)

Chest X-Ray: Key Findings

• Typically, won’t show any abnormality
• Important for assessment of other causes of respiratory disease, or other causes of exacerbation and/or worsening symptoms (e.g., pneumonia | foreign body in airways)

SYNOPSIS:

While targeted questions and examination are helpful, a good overall history and physical remain important to identify co-morbidities (e.g., sinusitis, rhinitis, GERD, other respiratory disorders, obstructive sleep apnea). It is also important to remain cognizant that multiple external factors can trigger an attack, including respiratory infections, smoking, allergies, exposure to cold or humid air, pollution, exercise, severe emotional and/or physical stress. Spirometry is currently the primary diagnostic tool for asthma.

KEY POINTS:

Severity of Asthma

• Asthma severity is determined by the following
  • Reported symptoms over the previous two to four weeks
  • Standardized questionnaires – e.g., the Asthma Control Test
    • Provides numerical score to determine if the symptoms are well controlled
• Current level of lung function: PEFR | FEV₁ | FEV₁/FVC
• Number of exacerbations requiring oral glucocorticoids in the previous year

Types of Asthma

Intermittent

• No interference with normal activities between exacerbations
• Daytime asthma symptoms: ≤2 days per week
• Nocturnal awakenings: ≤2 per month
• Use of short-acting beta agonists to relieve symptoms: ≤2 days per week
• FEV₁ between exacerbations: Within normal range (i.e., ≥80 percent of predicted)
• FEV₁/FVC ratio between exacerbations: Within normal range (based on age-adjusted values)
• Oral glucocorticoids requirements: ≤1 exacerbation per year
• Other circumstances
  • Use of Short-Acting Beta Agonists (SABAs) to prevent exercise-induced asthmatic symptoms (even if exercising more than twice per week)
  • Infrequent circumstances: Exposures such as cat encounter or URTI

Mild persistent

• Minor interference with normal activities
• Symptoms: >2 weekly (not daily)
• Nocturnal awakenings: 3 to 4 per month (not every week)
• Use of SABAs: > 2 days per week (Not daily)
• FEV₁: between exacerbations: Within normal range (≥80 percent of predicted)
• FEV₁/FVC ratio between exacerbations: Within normal range (based on age-adjusted values)
• Oral glucocorticoids requirements: ≥2 exacerbations per year

Moderate persistent

• Daily symptoms of asthma
  • Some limitation in normal activity
• Nocturnal awakenings: ≥1 per week
• Need for SABAs: Daily
• FEV₁: 60 to 80 percent predicted
• FEV₁/FVC: Below normal 

Severe persistent

• Symptoms of asthma throughout the day
  • Extreme limitation in normal activity
• Nocturnal awakenings: Nightly
• Need for SABAs: Several times per day
• FEV₁: <60 percent of predicted
• FEV₁/FVC: Below normal

When to refer to pulmonologist and/or allergist/ immunologist 

• Life-threatening asthma exacerbation 
• >2 bursts of oral glucocorticoids in a year 
• Asthma not controlled after three to six months of active therapy and appropriate monitoring 
• Unresponsive to therapy 
• Diagnosis of asthma is uncertain 
• Comorbid conditions that are complicating management such as
  • Nasal polyposis | Chronic sinusitis | Severe rhinitis | Allergic bronchopulmonary aspergillosis (see review below in ‘Learn More – Primary Sources), COPD, vocal cord dysfunction
• Additional diagnostic tests are needed such as
  • Skin testing for allergies | Bronchoscopy | Complete pulmonary function tests
• Potential candidate for allergen immunotherapy  

Learn More – Primary Sources

2020 Focused Updates to the Asthma Management Guidelines | NHLBI, NIH

CDC: Asthma Resources for Healthcare Professionals

Asthma Control Test (ACT)

American Thoracic Society: Asthma Center

Diagnosing Allergic Bronchopulmonary Aspergillosis: A Review

Related ObG Topics:

Asthma: The Stepwise Approach to Treatment

Fish Oil During Pregnancy: Reduction of Asthma Risk in Offspring? 

Does Late Preterm Birth Increase Risk of Asthma?