Asthma Flashcards
What is asthma?
Reversible airway obstruction which responds to bronchodilators such as salbutamol
Typical triggers of asthma?
Cold, infection, night time or early morning, exercise, animals, dust and strong emotions
Presentation suggesting asthma?
Episodic symptoms, diurnal variability, dry cough with wheeze and sob, history of atopic conditions eczema and hay fever, family history, bilateral widespread polyphonic wheeze
What indicates a viral induced condition?
Wheeze related to cough and cold
What does unilateral wheeze suggest?
Focal lesion or infection
First line investigations for asthma?
Fractional exhaled nitric oxide
Spirometry with bronchodilator reversibility
If after first line investigations there is uncertainty then use?
Peak flow variability 2-4 weeks
Direct bronchial challenge test with histamine or methacholine
Which are the reliever or rescue medication?
SABA- Adrenalin acts on smooth muscle causing dilation
Which are the maintenance or preventer medications?
ICS beclometasone
How do LAMA work?
Block acetylcholine receptors, which are stimulated by parasympathetic nervous system causing contraction
What do leukotrienes cause?
Inflammation, bronchoconstriction and mucus secretion
Theophylline mechanism and important point?
Relaxes bronchial smooth muscle and reduces inflammation.
Narrow therapeutic index toxic in excess, monitor 5 days after starting and 3 days after dose change
What is MART?
ICS and fast acting LABA
Order of drugs?
- SABA
- ICS
- LTRA
4.LABA - MART
- ICS to moderate dose
- ICS to high dose or LAMA or oral theophylline
- Specialist
How many people die with asthma every year in UK?
1000
What type of hypersensitivity is asthma?
1
What is the predominant response?
Th2
How is occupational asthma diagnosed?
Reduced peak flows during week and weekend
Occupational allergens include?
Flour and isocyanates (spray painting and foam moulding), platinum salts, resin, gluteraldehyde, proteolytic enzymes
Symptoms of asthma?
Cough, sob and wheeze/ chest tightness
Signs of asthma?
Expiratory wheeze on auscultation
Reduced PEFR
Spirometry results in asthma?
FEV1 Reduced, FVC normal and FEV1% less than 70
Why do FENO test?
Nitric oxide produced by 3 synthase, one which is inducible and levels tend to rise inflammatory cells (eosinophils)
Side effect of salbutamol?
Tremor
Side effects of ICS?
Stunted growth in children
Oral candidiasis
Examples of ICS?
Beclometasone dipropionate fluticasone and propionate
Children under 17 should have which tests?
Spirometry with bronchodilator reversibility. If negative then FeNO
When is FeNO positive?
Adults>=40 parts per billion and in children 35 parts per billion
Reversibility testing?
Improvement in FEV1 of 12% or more and increase in volume of 200ml in adults
In children, improvement in FEV1 of more than 12%
What is difference in low dose, moderate and high ICS?
Less than 400 micrograms, 400-800, more than 800
How to reduce dose of inhaled steroids?
25-50% at a time
How often should you consider stepping down?
3 months
Presentation of acute asthma
Progressively worsening sob
Accessory muscles
Tachypnoea
Symmetrical expiratory wheeze
Tight chest with reduced air entry
Moderate grading of acute asthma?
PEFR 50-75
Severe grading of Acute asthma?
PEFR 33-50
Resp rate>25
Heart rate>110
Unable to complete full sentences
Life threatening acute asthma?
PEFR less than 33
Sats less than 92
Becoming tired
No wheeze- silent chest
Haemodynamically unstable- shock
Bradycardia dysrhythmia or hypotension
Exhaustion, confusion or coma
How to treat moderate acute asthma?
Nebuliser beta 2 agonist- salbutamol 5mg
Nebuliser ipratoprium bromide
Steroids- oral prednisolone and IV hydrocortisone- 5days
Antibiotic if infection
Treatment for severe acute asthma?
Oxygen to maintain sats
Aminophylline infusion
IV salbutamol
Life threatening acute asthma treatment?
IV magnesium sulphate infusion
HDU/ICU
Intubation
ABGs in asthma?
Respiratory alkalosis blowing CO2 off, if tiring hypoxia and normal CO2- life threatening asthma. Respiratory acidosis- high CO2 very bad sign
What should you monitor when giving salbutamol?
Serum potassium- absorbed into cells. Can cause tachycardia.
When do you refer to specialist?
If more than 2 attacks in 12 months
What is near fatal asthma?
Raised CO2 or requiring mechanical ventilation with raised inflation pressures
When to do ABG?
Sats less than 92
When to do CXR?
Life threatening asthma, suspected pneumothorax, failure to respond to treatment
Criteria for discharge?
No oxygen or nebulisers for 12-24 hours
PEF more than 75
Inhaler technique checked
ITU/HDU treatment options?
Intubation and ventilate
ECMO- blood pumped outside body to machine which removes CO2 and puts oxygen into blood
