Acute Asthma Flashcards
What % of the population does asthma affect?
5-8%
What is asthma characterised by?
recurrent episodes of : -dyspnoea -cough -wheeze caused by reversible airways obstruction.
What 3 factors contribut to airway narrowing ?
1) bronchial muscle contraction
2) mucosal swelling / inflammation
3) increased mucus production
What are the symptoms of asthma?
- intermittent dyspnoea
- wheeze
- cough (often nocturnal)
- sputum
What are the precipitants of asthma?
- cold air
- exercise
- emotion
- allergens e.g. house dust mite, pollen, fur
- infection
- smoking
- pollution
- NSAIDs
- beta blockers
What is diurnal variation? (peak flow)
Patients who suffer from asthma may have variation in their symptoms or peak flow depending on the time of day.
-Marked morning dip in peak flow is common.
What are the associated symptoms of asthma apart form SOB, cough, wheeze, sputum?
- Reduced exercise ability.
- disturbed sleep (a sign of severe asthma)
- Acid reflux
- eczema, hay fever, allergy
What should you specifically ask about when taking a history from an asthma patient (apart from SOB, cough, wheeze, sputum)?
1) Precipitants (e.g. cold air, NSAIDs)
2) Diurnal variation (worse in morning? nightime cough)
3) Excerise tolerance
4) Disturbed sleep (sign of sever asthma)
5) Acid reflux
6) Eczema, hay fever, allergies
7) living conditions - pets, carpet, feather pillow.
8) Job (paint sprayers, welders, animal handler)
What are the examination signs of asthma?
- tachypnoea
- wheeze
- hyperinflated chest
- hyperresonant percussion note
- reduced air entry
What are the signs of a severe asthma attack?
- inability to complete sentences
- pulse > 110bpm
- resp rate >25/min
- Peak expiratory flow 33- 50% of predicted
What are the signs of a life threatening asthma attack?
- silent chest
- confusion
- exhaustion
- cyanosis (PaO2 < 8 KPa, PaCO2 4.6-6, SPO2 <92%)
- Bradycardia
- Peak expiratory flow <33%
What investigations should be done for an acute attack of asthma?
- Peak expiratory flow
- sputum culture
- FBC (raised WCC? infective trigger)
- U & E
- CRP
- Blood cultures (sepsis)
- ABG analysis (low PaO2, and low PaCO2) —> of PaCO2 raised send to ITU as it shows failing resp effort.
- CXR to exclude infection / pneumothorax
What does a raised PaCO2 in asthma indicate?
In an acute attack of asthma the ABG usually shows a low PaO2 and a low PaCO2 (hyperventilation). If the PaCO2 is raised this indicates a failing respiratory effort , the pt should be sent to intensive care. As this is fatal.
What drugs can trigger asthma?
- NSAIDS
- Beta Blockers
What are the investigations for chronic asthma?
- Peake expiratory flow rate
- spirometry (low FEV1/ FVC) —-> improved FEV1 after beta 2 agonist / steroids.
- CXR (hyperinflation)
- skin prick test for allergens
- Aspergillus serology