Asthma
Definition
- Excessive variation in expiratory flow
- Respiratory symptoms that vary overtime, that may be present or absent at any point in time
Pathophysiology
- Chronic inflammation
- Airway hyperresponsiveness
- Intermittent airway narrowing (bronchoconstriction, congestion, oedema, mucus)
- Can be controlled but not cured
- May represent a spectrum of diseases, may overlap with COPD in older people
- More likely in atopy
Dx
Lung function tests (clinical for young children), without current respiratory infection
- excessive variation in expiratory flow by any of (don't have to demonstrate hyperresponsiveness)
- increase in FEV1 of at least 12% or 200ml 10-15mins post bronchodilator
- increase in FEV1 of at least 12% or 200ml after 4 week trial of inhaled corticosteroids
- decrease in FEV1 of at least 12% or 200ml, or Peakflow of at least 20% after exercise
- reduction in FEV1 of 15-20% (depending on test) with airway hyperresponsiveness test (exercise challenge or bronchial provocation)
- variability of FEV1 of at least 20% with repeated testing
- Diurnal variability in Peakflow of 10%
If can't do lung function testing i.e. ~<5yo clinical
Sx wheeze, dyspnoea, tightness, cough
recurrent, worse at night and morning
Triggered by exercise, pets, cold air, damp air, emotions, laughing with no cold
Atopy
Response to treatment is the most important
Do not diagnose on cough alone, less likely if only with colds, moist cough, no wheeze, no response to treatment
Viral induced wheeze if only related to colds prior to PFT
DDX
If onset from very early life
- CF
- CLD of prematurity
- Primary ciliary dyskinesis
- BPD
- Congenital anomaly
Creps that don't clear on coughing
- pneumonia
- Bronchiectasis
FTT ?systemic
choking / vomiting / aspiration
stridor
abnormal voice
clubbing: CF, bronchiectasis
Moist: CF, bronchiectasis, chronic bronchitis, aspiration, immunodeficiency, PCDyskinesia
Focal lung signs: Pneumonia
Harrisons sulcus / Pectus excavatum if mild ?uncontrolled, if severe ?alternate
Cough absent at night (? habit / psychogenic)
Triggers
Pattern
Intermittent
- Infrequent episodic: symptom free for >6w between flares
- Frequent episodic: symptom free for <6w between flares
- Mild
- (FEV1 >80% + 1 of)
- day symptoms: not daily but weekly
- night symptoms not weekly but monthly
- no activity / sleep restriction
- flare free >6w
- Mod
- (FEV1 60-80%)
- day symptoms: daily
- night symptoms: weekly
- activity/sleep restricted: sometimes
- flare free >6w
- Severe (inc frequent persistent)
- (FEV1 <60%)
- day symptoms: continual
- night symptoms: frequent
- activity/sleep restricted: frequent
- flare free <6w
Initial preventer
- 0-1y
- VIW / single trigger / intermittant: no preventer
- persistent / multiple triggers: Specialist
- 1-2y
- VIW / single trigger / intermittant: no preventer
- persistent / multiple-trigger
- ICS (low) if interrupting sleep or play OTHERWISE
- Cromoglycate 10mg TDS
- 2-5y
- VIW / single trigger / infrequent intermittant: no preventer
- frequent intermittent / mild persistent / mild multi-trigger: montelukast 4mg PO (if poor response CHANGE to ICS (low))
- mod/sev persistent, mod/sev multi-trigger: ICS (low) (if poor response ADD montelukast and specialist)
- >5y
- infrequent intermittant: no preventer
- frequent intermittent / mild persistent: montelukast 5mg PO (or chromone) (if poor response CHANGE to ICS (low))
- mod/sev persistent: ICS (low) (if poor response ADD montelukast OR ↑ ICS (high) OR LABA/ICS (low))
- Exercise induced asthma
- If Asthma Dx
- current control partial/poor: treat as per usual
- current control partial/good:
- If on LABA change to SABA pre exercise
- 2-5y or >6y and daily: consider montelukast (sole if no preventer, with ICS if already on)
- >6y and not daily: Salbutamol 15 min prior to exercise
- if poor response and ICS (low)
- if exercise symptoms on most days start ICS (low) or increase to ICS (high)
- If no Dx Asthma i.e. standard LFTs NAD
- ? trial ventolin 15 mins prior
- ? trial preventer
- ? indirect challenge testing (for exercise asthma) and exercise testing (for cardiopulmonary fitness)
- NB check Rx against ASADA permitted list
- If Asthma Dx
Rx (All puffers via spacer +/- facemask depending on age)
Beta2 agonists (Inh)
- Short acting
- Salbutamol (Ventolin/Asmol/Airomir)
- Terbutaline (Bricanyl)
- Long acting
- Eformoterol (as Symbicort with budesonide, or Flutiform with fluticasone p.)
- Salmeterol (as Seretide with fluticasone p.)
- Vilanterol (as Breo with fluticasone f.)
- Ciclesonide Low (80-160) High (160-320) (Alvesco)
- Fluticasone p. Low (100-200) High (200-400) (Flixotide)
- Beclomethasone Low (100-200) High (200-400) (Qvar)
- Bedesonide Low (200-400) High (400-800) (Pulmicort)
- Ipratropium (Atrovent)
- Tiotropium (Spiriva)
- Aminophylline (IV)
- Theophylline (PO)
- Cromoglycate (Intal)
- Nedocromil (Tilade)
- Montelukast (Singulair) PO: MOA reduced bronchoconstriction and inflammation NB neuropsychologist side effects
- Omalizumab (Xolair) SC
Non-invasive PPV without sedation
I+V (?plus external chest pressure to assist expiration)
Goal planning with parents (no hospitalisations, not missing school)
Education and Rx training
Avoid triggers
Tobacco, Diet, Exercise, Wt, immunisations
Manage comorbidities
- Allergic rhinitis
- SABA only (if >12 ?Symbicort as preventer and reliever)
- SABA + ICS (low) or montelukast or cromone
- SABA + ICS (high) or combined ICS (low) and montelekast or LABA
Monitor: Control on prevention over last 4 weeks
- Good control: no limitations on activities, SABA 2 or </week resolve within mins, not at night
- Partial: missing any of above (SABA still relieves within mins)
- Poor: SABA not relieving within mins OR any 3 partial feature within the same week
poor response: review Dx and inh technique
Start Clinical Pathway
Use asthma discharge summary
If sats drop but CO2/clinically otherwise stable / improving ?VQ mismatch > wean salbutamol
Clinical trials
Fevipiprant: prostaglandin D2 receptor 2 antagonist