From the Guidelines
A diagnosis of asthma should be established by determining the presence of episodic symptoms of airflow obstruction or airway hyperresponsiveness, airflow obstruction that is at least partially reversible, and a history of specific symptoms such as cough, wheeze, and difficulty breathing, as outlined in the expert panel report 3 (epr-3) guidelines 1. To diagnose asthma, a comprehensive evaluation is necessary, including a detailed medical history, physical examination, and lung function tests. The key symptom indicators for considering a diagnosis of asthma include episodic symptoms of airflow obstruction or airway hyperresponsiveness, such as cough, wheeze, and difficulty breathing, which occur or worsen in the presence of specific triggers like exercise, viral infections, or allergens 1. Some of the key points to consider in the diagnosis of asthma include:
- Episodic symptoms of airflow obstruction or airway hyperresponsiveness
- Airflow obstruction that is at least partially reversible, measured by spirometry, with an increase in FEV1 of >200 mL and 12% from baseline after inhalation of a short-acting beta-2 agonist (SABA) 1
- History of symptoms such as cough, wheeze, and difficulty breathing, which occur or worsen at night or in response to specific triggers
- Physical examination findings, such as wheezing, hyperexpansion of the thorax, and use of accessory muscles, although these may be absent between episodes 1
- Spirometry is an essential objective measure to establish the diagnosis of asthma, as it can demonstrate obstruction and assess reversibility in patients 5 years of age and older 1. It is also important to consider a differential diagnosis of asthma, as recurrent episodes of cough and wheezing can be caused by other conditions, and to rule out alternative diagnoses through additional tests if necessary 1.
From the Research
Diagnosis of Asthma
- Asthma is a heterogeneous disease, encompassing both atopic and non-atopic phenotypes, and its diagnosis is based on the combined presence of typical symptoms and objective tests of lung function 2.
- The diagnosis of asthma is made through a combination of clinical assessment and diagnostic testing, including symptoms such as cough, dyspnea, and wheezing, as well as physical exam findings like hyperinflation, wheezing, and increased work of breathing 3.
- Clinical diagnosis of asthma is often based on the presence of symptoms, but the presence of these symptoms is not exclusive to asthma, and clinical correlation with spirometry and other diagnostic testing is essential 4.
Diagnostic Testing
- Spirometry with bronchodilator reversibility testing remains the mainstay of asthma diagnostic testing for children and adults, and repetition of the test over several time points may be necessary to confirm airway obstruction and variability thereof 2.
- Repeated peak flow measurement is relatively simple to implement in a clinical and home setting, and bronchial challenge testing is reserved for patients in whom the aforementioned testing has been unrevealing but clinical suspicion remains 2.
- Methacholine challenge tests can be used to assess airway hyperreactivity in asthmatic patients, and the diagnostic accuracy of different lung function parameters can be compared to evaluate dose-response characteristics 5.
Clinical Assessment
- Patients with asthma present with varied symptomatology and exam findings, and the physical exam can demonstrate hyperinflation, wheezing, and increased work of breathing, but most patients will present with a normal pulmonary exam because they are between episodes 3.
- The diagnosis of asthma in the pediatric population may be more difficult because the classic symptoms may not be present in many of those patients, and the astute physician will rely on all three factors - clinical history, physical exam, and diagnostic testing - when making the diagnosis 3.
- The focus of care should be toward control of the disease once a diagnosis of asthma is established, and the pathophysiology, diagnosis, and clinical assessment of asthma in the adult patient population should be considered 4.