Reading Time:
Pathology
Chronic, reversible airway inflammation causing obstruction to airflow due to increased sensitivity to a variety of stimuli
2 phases:
• Early reaction (minutes): bronchospasm
• Late reaction (3-5 hours): oedema and mucus
Aetiology
Genetic: Polygenic inheritance, atopy
Environmental: house dust mites, pet-derived allergens, smoke, pollen and work
place agents, NSAIDs, beta-blockers, cold weather
Signs
Polyphonic wheeze on auscultation, tachypnoea, diurnal variation
Symptoms
Wheeze, shortness of breath, cough, chest tightness.
Investigations
Spirometry: >15% improvement after B2 agonist/steroid trial
Peak Expiratory Flow (PEF): >20% diurnal variation for >3days
Chest X-Ray: To exclude other diagnoses e.g. pneumothorax, infection
ABG: To assess for hypoxia or acid base disturbance
Treatment
Assessment of severity: To classify Moderate, Acute Severe or Life-threatening
Supplementary oxygen: Aim to keep saturations between 94-98%
B2 agonist bronchodilators: inhaled or nebulised
Ipratropium bromide: Acute severe, life threatening or poor B2 agonist response
Steroids: Given in all cases of acute asthma
Magnesium sulphate: consider a single dose in near fatal or life-threatening asthma
ITU: if life threatening or near-fatal asthma failing to respond to initial therapy
Prognosis
Mortality from acute attacks is ~1200 per year
Pneumothorax, bronchiectasis
Key Facts
Lorem ipsum dolor sit amet, sapien platea morbi dolor lacus nunc, nunc ullamcorper. Felis aliquet egestas vitae, nibh ante quis quis dolor sed mauris.
Key Images
Lorem ipsum dolor sit amet, sapien platea morbi dolor lacus nunc, nunc ullamcorper. Felis aliquet egestas vitae, nibh ante quis quis dolor sed mauris.
Key References
Lorem ipsum dolor sit amet, sapien platea morbi dolor lacus nunc, nunc ullamcorper. Felis aliquet egestas vitae, nibh ante quis quis dolor sed mauris.