Chronic asthma

Introduction

• Establish diagnosis formally
• Identify and prevent triggers
• Stepwise therapy
• Education
• Refractory asthma
• Special situations

Initial assessment

• Good control (all of)
  • Daytime symptoms <=2 times per week
  • Need for reliever <=2 days per week
  • No limitation of activity
  • No symptoms during night or on waking
• Partial control (one or two of)
  • Daytime symptoms >2 times per week
  • Need for reliever >2 days per week
  • Any limitation of activity
  • Any symptoms at night or on waking
• Poor control (three or more of above)

Stepwise therapy

• Symptoms < twice per month and no flare-up requiring OCS in last 12 months
  • SABA – Salbutamol
• Symptoms > twice per month or waking at least once in last month or oral steroids required for an exacerbation in last 12 months
  • Low-dose ICS + SABA (alternatives are montelukast or cromones)
• Waking at least once in last month + frequent daytime symptoms
  • Moderate-high dose ICS + SABA
• If ongoing poor symptom control step-up to:
  • ICS/LABA combination (low dose) or budesonide/formoterol (low dose) maintenance and reliever
• If still poor symptom control
  • ICA/LABA combination (moderate-high dose) and consider referral

Inhaled corticosteroids

Other preventers

• Montelukast
  • Less effective than ICS but can be considered if:
    • Intolerable dysphonia with inhaled corticosteroids despite correct inhaler technique and use of a spacer
    • People who refuse other options
• Cromones
  • Less effective than ICS but can be consdiered if:
    • People cannot tolerate or don’t want to take ICS
    • Symptoms limited to exercise-induced bronchospasm

Prognostic factors

• Risk factors for increased exacerbations
  • Poor asthma control
  • Any asthma exacerbation in last 12 months
  • Other chronic lung disease
  • Poor lung function
  • Difficulty perceiving symptoms/severity
  • Eosinophilic airway inflammation
  • Smoking/passive
  • Low SES
  • Use of illegal substances
  • Major psychosocial issues
  • Mental health disorders

Prognostic factors

• Risk factors for life-threatening asthma
  • Previous ICU
  • 2 or more hospitalisations in last year for asthma
  • 3 or more ED visits for asthma in last year
  • Hospitalisations or ED visits in the last month for asthma
  • High SABA use (>2 canisters per month)
  • History of delayed presentations
  • History of brittle asthma
  • Cardiovascular disease
  • Sensitivity to unavoidable allergen
  • Inadequate treatment
  • Experience of side effects from oral corticosteroids (may prevent presentation)
  • Lack of written asthma action plan
  • Poor access to healthcare, low SES, mental health, substance abuse

Prognostic factors

• Factors associated with accelerated decline in lung function
  • Chronic mucous hypersecretion
  • Severe asthma exacerbation in patient not on ICS
  • Poor lung function
  • Eosinophilic airway inflammation
  • Cigarette smoke exposure
  • Occupational asthma

Refractory asthma

• 5% difficult to control
• Two major pattern: Persistent symptoms vs. brittle
• Most common cause is non-compliance, especially ICS
  • Compliance may be improved by combination ICS + LABA
• High allergen levels, unidentified occupational agents, severe rhinosinusitis
• GORD is common but does not seem to be a significant factor in poor control
• Chronic Mycoplasma/Chlamydia pneumophila infection and may benefit from coarse of doxycycline
• Beta-blockers, aspirin, COX-inhibitors
• Severe pre-menstrual symptoms may warrant progesterone therapy
• Vocal cord dysfunction syndrome
  • May be identified by large discrepancy in FEV1 and PEF with relatively normal airway resistance
  • Direct laryngoscopy is confirmatory

Brittle asthma

• Type I brittle asthma
  • Persistent pattern of variability and may require oral corticosteroids or, at times, continuous salbutamol infusions
• Type 2 brittle asthma
  • Generally normal or near-normal lung function with precipitous, unpredictable collapse and possible death
  • Do not respond well to corticosteroids or inhaled bronchodilators
  • Most effective therapy is SC adrenaline, suggesting that worsening is likely to be localised airway anaphylaxis
  • Look for food allergy

Special considerations

• Aspirin-sensitive asthma
  • 1% of asthmatics become worse with aspirin or COX inhibitors
  • Much more common in those with severe asthma and frequent hospitalisations
  • Usually preceded by perennial rhinitis and nasal polyps in non-atopic patients with late-onset asthma
  • Aspirin provokes rhinorrhoea, conjunctival irritation, facial flushing and wheezing
  • Genetic predisposition
  • Selective COX-2 inhibitors appear safe
  • Responds to usual therapy with ICS

Special considerations

• Pregnancy
  • 1/3 improve, 1/3 deteriorate and 1/3 are unchanged
  • Maternal complications slightly increased and perinatal mortality nearly doubles
  • Drugs used in asthma have been shown to be safe in pregnancy and outweigh any theoretical risk of harm
  • Use prednisolone is systemic steroids are required as cannot be converted to active prednisone by foetal liver
• Smoking
  • 20% of asthmatics smoke
  • Have more severe disease, more frequent admissions, more rapid decline in lung function and higher risk of death from asthma
  • Interferes with anti-inflammatory effects of steroids
  • Smoking cessation improves lung function and reverses steroid resistance
  • On cessation, temporary worsening can occur due to loss of bronchodilating effect of nitrous oxide in cigarette smoke

Special considerations

• Bronchopulmonary aspergillosis (BPA)
  • Uncommon and results from allergic pulmonary reaction to spores of Aspergillus fumigatus
  • Fleeting eosinophilic infiltrates in the lungs, particularly upper lobes
  • Airways block with mucoid plugs with coughing up of brown material or haemoptysis
  • May result in bronchiectasis
  • Asthma management remains unchanged but oral coarse of steroids required in exacerbations or pulmonary shadowing is found
  • Oral itraconazole is beneficial in preventing exacerbations

Last Updated on October 28, 2020 by Andrew Crofton