BTS/SIGN Asthma guidance

Latest revision 2019.

Diagnosis is about probability – high probability is recurrent episodes, documented wheeze, atopic history, documented variable PEF or FEV1. Start treatment, “typically” 6 weeks inhaled corticosteroids (ICS). If good response to treatment, then diagnosis is confirmed.

If intermediate probability then spirometry with reversibility is preferred initial test for children old enough to do it (Grade D recommendation). If spirometry normal, then do challenge tests and/or FeNO measurement. For younger children, watchful waiting or trial of treatment.

Red flags –

  • Focal chest signs
  • Abnormal voice or cry
  • Failure to thrive
  • Vomiting
  • Wet/productive cough
  • Nasal polyps

Management

Self management education, written personalized plan.

Ask specifically about medication use and assess prescriptions. Explore attitudes to medication as well as practical barriers to adherence.

Not for routine house dust mite avoidance measures. Avoid smoking and second hand smoke.

Weight loss (including dietary and exercise programmes) for overweight and obese. Breathing exercise programmes can be offered as an adjuvant to pharmacological treatment.

Treatment

ICS are recommended preventer. Give twice daily until good control established.

5yrs and over, if add-on is required then choice between inhaled long acting beta agonist (LABA) or leukotriene receptor antagonist (LTRA). Only then increase dose of ICS from very low to low.

For exercise induced symptoms, generally just a sign that inadequate control! But if otherwise well controlled then give inhaled short acting beta agonist immediately prior to exercise. Then choice between LRTA, LABA, cromoglicate or theophylline.

Acute Severe Asthma

  • Sats under 92%
  • PEF 33-50% of best or predicted
  • Can’t complete sentences in one breath, or too breathless to feed
  • HR >140 (under 5), >125 (over 5)
  • RR>40 (under 5), >30 (over 5)

Life threatening defined as:

  • PEF <33%
  • Exhaustion, poor resp effort [tautology?]
  • Hypotension
  • Cyanosis
  • Silent chest
  • Confusion

Treat –

  • Oxygen
  • MDI plus spacer if mild/moderate
  • If refractory to beta agonist, add ipratropium 250mcg mixed into beta agonist [same dose for everyone]
  • “Consider adding 150mg magnesium sulphate to each neb in first hour if symptoms started <6hrs and presenting with sats <92%” [Recommendation based on MAGNETIC trial – no overall benefit but better Asthma Severity Score at 1 hour for this subgroup – see below] – 2.5ml of 250mmol/ml (1000mg made up to 16ml)
  • Give oral steroids early, dose by age.

Second line treatment –

  • Consider single IV bolus of salbutamol (15mcg/kg over 10mins)
  • Consider aminophylline for severe asthma unresponsive to maximal doses of bronchodilators and steroids.
  • Consider IV MgSO4 40mg/kg/d

Poor evidence for Neb magnesium in children or adults, limited evidence for IV. Systematic review in children (2018) – pulmonary function improved, hospitalization and further treatment decreased. No such evidence for Nebs.

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