Asthma Flashcards
Definition of asthma
Chronic inflammatory airway disease leading to variable airway obstruction
Type 1 hypersensitivity reaction
Risk factors for asthma
Personal or family history ofatopy
Antenatal factors: maternal smoking, viral infection during pregnancy (especially RSV)
Low birth weight
Not being breastfed
Maternal smoking around child
Exposure to high concentrations of allergens (e.g. house dust mite)
Air pollution
Common asthma triggers
Dust (house dust mites)
Animals
Cold air
Exercise
Smoke
Fool allergens (e.g. peanuts, shellfish, eggs)
Symptoms of asthma
Cough (often worse at night)
Dyspnoea
Wheeze
Tight chest
Asthma signs
Expiratory wheeze on auscultation
Reduced PEFR
Pathophysiology of asthma
Smooth muscle in airways is hypersensitive, and responds to stimuli by constricting and causing airflow obstruction
Asthma investigations
Spirometry
Forced expiratory volume (FEV1) - significantly reduced
Forced vital capacity (FVC) - normal
Asthma investigations
Spirometry
Fractional exhaled nitric oxide (FeNO)
Asthma investigations
FeNO
Nitric oxide produced by 3 types of nitric oxide synthases (NOS)
One of the types is inducible (iNOS) and levels tend to rise in inflammatory cells, particularly eosinophils
Levels of NO therefore typically correlate with levels of inflammation
Asthma management in under 5s
1) SABA inhaler e.g. salbutamol as required
2) Add low dose corticosteroid inhaler or leukotriene antagonist e.g. oral montelukast
3) Add other option from step 2
4) Refer to specialist
Asthma management in 5-12s
1) SABA
2) SABA + paeds low-dose ICS
3) SABA + paeds low-dose IC + LTRA
4) SABA + paeds low-dose ICS + LABA
5) SABA + switch ICS/LABA for MART (including paeds low-dose ICS)
6) SABA + paeds low-dose ICS MART or change back to fixed dose of moderate-dose ICS and separate LABA
7) SABA + one of the following:
- Increase ICS to paeds high-dose
- Trial of additional drug e.g. theophylline
- Seek advice from asthma expert HCP
Maintenance and reliever therapy (MART)
Form of combined ICS and LABA treatment in which a single inhaler (containing ICS and fast-acting LABA) is used for both daily maintenance therapy and relief of symptoms as required
Inhaler technique (without spacer)
Remove the cap
Shake the inhaler (depending on the type)
Sit or stand up straight
Lift the chin slightly
Fully exhale
Make a tight seal around the inhaler between the lips
Take a steady breath in whilst pressing the canister
Continue breathing for 3 – 4 seconds after pressing the canister
Hold the breath for 10 seconds or as long as comfortably possible
Wait 30 seconds before giving a further dose
Inhaler technique (with spacer)
Assemble the spacer
Shake the inhaler (depending on the type)
Attach the inhaler to the correct end
Sit or stand up straight
Lift the chin slightly
Make a seal around the spacer mouthpiece or place the mask over the face
Spray the dose into the spacer
Take steady breaths in and out 5 times until the mist is fully inhaled
Acute asthma definition
Rapid deterioration in the symptoms of asthma
Clinical features of acute asthma
Progressively worsening shortness of breath
Signs of respiratory distress
Tachypnoea
Expiratory wheezeon auscultation heardthroughout the chest
Chest can sound “tight” on auscultation, with reduced air entry
Silent chest (life-threatening, easily mistaken for no wheeze/distress)
Features of moderate asthma
Peak flow >50% predicted
Normal speech
Features of severe asthma
Peak flow <50% predicted
Saturations <92%
Unable to complete sentences in one breath
Signs of respiratory distress
RR >40 in 1-5s, >30 in >5s
HR >140 in 1-5s, >125 in >5s
Features of life-threatening asthma
Peak flow <35% of predicted
Saturated <92%
Exhaustion and poor respiratory effort
Hypotension
Silent chest
Cyanosis
Altered consciousness/confusion
Management of acute asthma
Supplementary O2 (if sats <90 or working hard)
Bronchodilators (salbutamol, ipratropium, magnesium sulphate)
Steroids (prednisolone orally, hydrocortisone IV)
Abx if bacterial cause suspected (amoxicillin or erythromycin)
Outline bronchodilator step-up
Inhaled or nebulised salbutamol(beta-2 agonist)
Inhaled or nebulised ipratropium bromide(anti-muscarinic)
IVmagnesium sulphate
IVaminophylline
Mild acute asthma management
Managed as outpatient with regular salbutamol inhalers via spacer
4-6 puffs every 4hrs
Management of moderate to severe acute asthma
Stepwise approach until control achieved
Salbutamol inhalers via spacer starting with 10 puffs every 2hrs
Nebulisers with salbutamol/ipratropium bromide
Oral prednisolone
IV hydrocortisone
IV magnesium sulphate
IV salbutamol
IV aminiphylline
If still not controlled, call anaesthetist & ITU
Prednisolone dose
2-5yrs: 20mg OD
> 5yrs: 30-40mg OD
