Pathology: Chronic,reversible airway inflammation causing obstruction to airflow due to increasedsensitivity to a variety of stimuli
2phases:
· Early reaction (minutes):bronchospasm
· Late reaction (3-5 hours): oedemaand mucus
Aetiology: Genetic: Polygenic inheritance, atopy
Environmental: house dust mites, pet-derivedallergens, smoke, pollen and
workplace agents, NSAIDs, beta-blockers, cold weather
Symptoms: Wheeze,shortness of breath, cough, chest tightness.
Signs: Polyphonicwheeze on auscultation, tachypnoea, diurnal variation
Investigations: Spirometry: >15% improvement after B2agonist/steroid trial
Peak Expiratory Flow (PEF): >20% diurnal variation for>3days
Hypersensitivity Testing: e.g. skin prick tests, RAST, totalIgE level
Chest X-Ray: To exclude pneumothorax orinfection
Treatment: Treatment is based on Figure 2.6 andtreatment regimes should be stepped down
after a period of well-controlled asthma forat least 3 months
Figure 2.5 ChronicAsthma Treatment Protocol
Complications: Persistent symptoms, infections,pneumothorax, long-term steroids, bronchiectasis
Prognosis: Generallyvery good
