Airway Disease

Airway Disease

Acute Asthma


Pathology:                   Chronic,reversible airway inflammation causing obstruction to airflow due to increasedsensitivity to a variety of stimuli


·       Early reaction (minutes):bronchospasm

·       Late reaction (3-5 hours): oedemaand mucus


Aetiology:                   Genetic: Polygenic inheritance, atopy

Environmental: house dust mites, pet-derived allergens,smoke, pollen and work  

                                 place 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

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 classifyModerate, 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 orpoor B2 agonist response

Steroids: Given in all cases of acute asthma

Magnesium sulphate: consider a single dose in near fatal orlife-threatening asthma

ITU: if life threatening or near-fatal asthma failingto respond to initial therapy


Complications:    Pneumothorax,bronchiectasis


Prognosis:             Mortalityfrom acute attacks is ~1200 per year


Text Box: Assessment Of Acute Asthma Severity
o	PEF 50-75% of best/predicted 
o	Increasing symptoms

Acute Severe: 
o	PEF 33-50% of best/predicted 
o	Tachypnoea (Respiratory rate>25) 
o	Tachycardia (Pulse rate >110) 
o	Inability to complete a sentence in one breath

o	PEF <33% best or predicted
o	Saturation <92%
o	Cyanosis
o	Hypotension
o	Exhaustion/confusion
o	Silent chest
o	Tachy/bradycardia

Mnemonic for Life Threatening Asthma Features: ‘33-92 CHEST’
















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