Asthma diagnosis
The table below (from the 2009 BTS/SIGN guidelines) lists the factors that increase or decrease the probability of the presentation being asthma:
If from history/examination you believe there is a:
- high probability the patient has asthma --> being a trial of treatment
- intermediate probability of asthma --> perform spirometry:
- FEV1/FVC <0.7 - trial asthma treatment
- FEV1/FVC >0.7 - refer to specialist
After a trial of treatment >400mls improvement in FEV1 or PEFR >15% is significant
In a peakflow diary, look for diurnal variation >25%
Treatment of asthma
Treatment of asthma follows a stepwise approach (BTS/SIGN guidelines):
- Mild intermittent asthma
- SABA (short-acting inhaled beta 2 agonist) PRN
- salamol, salbutamol
- Regular preventor therapy
- corticosteroid 200-800mcg per day
- beclometasone, fluticasone, budesonide
- Initial add-on therapy
- LABA (long-acting inhaled beta 2 agonist (eg salmeterol))
- if this doesn't work, stop and trial an oral therapy such as leukotriene receptor antagonist or theophylline
- Persistant poor control
- increase steroid inhaler up to 2000mcg per day
- add leukotriene receptor antagonist or theophylline
- Continuous or frequent oral steroids
If stable for 3 months, consider stepping down a step.
Severity of asthma
In acute asthma attacks, severity may be graded as follows:
Severe:
- unable to complete sentences
- RR>25
- PEFR<50% predicted or best
- pulse >110
Life-threatening:
- silent chest
- PEFR <33% predicted or best
- bradycardia
- hypotension
- normal or raised CO2
- exhaustion
Management of acute severe asthma
Think 'O! sip Ma':
- high flow oxygen
- 5mg salbutamol neb
- 500mcg ipratropium neb
- 30mg prednisolone (or 100mg hydrocortisone IV)
- magnesium 1.2g and aminophylline if still not improving
Now for a battle with cor pulmonale...
