Diagnosis and Tests for Asthma
The first step in providing optimal care to patients with asthma is accurate diagnosis of the condition. Clinical evaluation should include a precise description of the symptoms, as in many patients, particularly children, asthma may present as chronic cough with few associated features. Similarly, it may present as isolated dyspnea in the elderly patients.
In the clinical setting, asthma is diagnosed based on the history, physical examination and physiological testing. A thorough occupational history is crucial to identify patients with work-related asthma.
Diagnosis of asthma in children is based on a compilation and review of the patient’s medical history and subsequent improvement with an inhaled bronchodilator medication.
In adults, lung function test with a peak flow meter which tests airway restriction by looking at both the diurnal variation and any reversibility following inhaled bronchodilators can help in the diagnosis.
The basic measurement is peak flow rates. The British Thoracic Society uses the following diagnostic criteria: 1
- Difference of ≥20% in peak flow on at least three days in a week for at least two weeks
- Improvement of ≥20% in peak flow following treatment
- Decrease of ≥20% in peak flow following exposure to a trigger
Use of a peak flow meter on an ongoing basis helps in self-monitoring of asthma. Subsequent to pulmonary (lung) function test, radiological studies such as chest X-ray or CT scan will help to exclude the possibility of other lung diseases.
Allergy testing is helpful in identifying allergens in patients with persistent asthma.
Related Articles...
Lung Function Tests
Peak Flow Meter
Written by: Healthplus24 team
Date last modified: July 03, 2011
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