Asthma

Asthma is characterised by phases of normalcy punctuated by attacks of breathlessness, wheeze and cough. It can present at any age and can have different clinical presentations. The only characteristics that are certain about asthma are itsvariability and its unpredictability.

What are the characteristics of asthmatic symptoms?

Asthma is characterised by breathlessness, cough, wheeze and chest tightness especially at night or in early morning 3.The severity of these symptoms is variable. Symptoms occur in episodes. These may occur abruptly or may develop over a period of days or weeks.

Some patients complain of asthmatic attacks mainly at night or in early morning. These episodes typically occur between 4 am and 6 am in the morning and they tend to wake up the patient. The mostcommon symptomof these patientsis breathlessness that may be due to dynamic lung hyperinflation leading to difficult inspiration. Wheezing is usually polyphonic in nature due to its origin from many airways of different calibre. The cough is usually dry but sometimes may be associated with small amounts of sticky sputum. Sputum, when present, is white or green in colour indicative of peroxidase released by eosinophils and neutrophils.

What are the trigger factors of asthma?

Trigger factors of asthma

Which tests are useful in a patient with asthma?

Initial diagnosis is based on clinical history and investigations are done mainly to confirm the diagnosis. Pulmonary function tests are done in a patient with asthma to demonstrate reversible and variable airway obstruction. Tests to measure airway inflammation and to assess atopy are also useful in patients with asthma.

1. To measure magnitude of airway obstruction

These tests form the mainstay of diagnosis and assessment of severity airflow limitation in

asthma.

1. Spirometry
2. Peak flow meter testing
3. To measure Hyper-responsiveness of airways:Bronchoprovocation testing
4. To measure airway inflammation
5. Exhaled nitric oxide (FeNO)
6. Sputum tests

2. How to identify triggers of asthma?

Clinical history is an important tool to identifytrigger factors of an asthmatic patient. Allergic triggerfactors can be identified by allergy tests. Allergy testsare based on the principle of presence of allergen

specificIgE in the tissues. These can be performed byestimation of specific IgE in blood or by skin pricktests.

Blood tests for allergen- specific IgE

Allergy skin prick test