08 Jan What are the clinical presentations associated with exposure to bushfire smoke?
Whilst many Australian communities are experiencing direct and immediate threats from bushfires this summer, so too are the general population in the form of environmental exposure to air pollutants. Over the course of the bushfire season it is expected that clinicians will experience an increase in patients presenting with respiratory distress. The risk is greater in immediate bushfire zones, however, pollutants from fires can travel hundreds of kilometres and adversely affect health in secondary zones. Furthermore, because smoke can cover large geographical areas, including major cities, it has the potential to affect millions of people.
For those patients living with pre-diagnosed respiratory conditions, such as asthma, COPD and chronic bronchitis, the risk is greater and it is advised that asthma management be included in their fire safety survival plan. These people may experience an increase in dyspnoea associated with wheeze, cough, increased mucous production and may be refractory to respiratory inhalers such as SABA/LABA/LAMA/ICS. As a first line of action Asthma Australia recommend patients:
- Follow your personal written asthma action plan
- If you don’t have an action plan, take 4 separate puffs of a blue/grey reliever
- If the symptoms aren’t going away or are getting worse, then follow the steps in “First Aid for Asthma”.
Other at-risk groups include those with existing heart conditions, pregnant women, older people and young children. Those in these high-risk groups are going to feel the effects of bushfire smoke more than the general population, however, healthy people will also experience adverse health as a result of prolonged exposure.
Bushfire smoke is a mixture of differently sized particles with larger micron particulate matter contributing to the visual haze we often see blanketing the region. During this time, it is common for patients to present with acute eye irritation and nasopharyngeal discomfort which can be treated accordingly. However, smoke also contains small micron particulate matter (PM2.5) in combination with water vapour and gases, including carbon monoxide, carbon dioxide and nitrogen oxides. This unique composition is often not visible to the naked eye and is demonstrated by elevated air quality index readings even on bright, sunny days. These particles are aspirated into the deepest segments of the lung and cause inflammation and may affect gas diffusion in affected patients. In the general population sustained exposure to these pollutants often manifest as irritating coughs, mild dyspnoea and rhinitis-like symptoms. Due to the “filter” effect of the nasopharyngeal portion of the upper respiratory system, in a clinical setting we are seeing an increase in eosinophilic inflammation, as demonstrated by elevated exhaled nitric oxide (FeNO). This inflammation can play a role in mucociliary clearance, bronchial smooth muscle tone and sensitive cough reflex.
During this challenging time, we advise clinicians to closely monitor at-risk patients as well as being aware of symptoms which may adversely affect ADL in the general population.