Asthma (recurrent Wheezing)

Clinical Description

Asthma is chronic inflammatory airway disease characterized by recurrent reversible airway obstruction, increased responsiveness of bronchial tree to a variety of stimuli resulting into recurrent episodes of wheezing, cough, chest tightness and shortness of breath. Triggers include house dust mite, fumes, perfumes, pollen, infection, pets hair, smoke, air pollution, emotions, infection, exercise, drugs (e.g., Aspirin/NSAIDs, beta-blockers such as propranolol), food (e.g. milk, peanut, egg, fish, wheat), weather change etc.

Asthma Phenotypes:

• Allergic asthma phenotype: easy to recognize and begins in childhood.
• Associated with a past and/or family history of allergic disease such as eczema, allergic rhinitis, conjunctivitis or food or drug allergy. Eosinophilic inflammation and respond well to inhaled corticosteroid (ICS) treatment.
• Non-allergic phenotype: in some adults and have neutrophilic or eosinophilic inflammation and may respond less to inhaled corticosteroid
• Occupation related asthma: symptoms may be triggered by work environment exposures
• Asthma with fixed airway obstruction: long-standing asthma develop fixed airflow limitation due to airway wall remodeling.
• Asthma with obesity: some obese asthma patients have little eosinophilic airway inflammation
• Exercise induced asthma: some patients/athletes have asthma symptoms during or after exercise

Signs and Symptoms

• Wheezing
• Chest tightness/breathlessness
• Coughing
• Nasal polyp and eczema (in some allergic asthma patients)
• Wheezes and respiratory distress (if during attack)
• May have normal physical examination (in between asthma attacks)

Investigations

• Asthma diagnosis is mainly based on classical recurrent nocturnal and daytime respiratory symptoms +/-wheezes on physical examination.
• Full blood count: mildly high eosinophil count in allergic asthma phenotype
• In some central/private hospitals: high total IgE (in allergic asthma)
• Spirometry: Reduced FEV1, FEV1/FVC <70% with reversible obstruction (increase in

FEV1 by 200ml and 12% post-bronchodilator).

Note: Patient with long standing uncontrolled asthma may develop irreversible airway obstruction due to airway remodeling. Spirometry can be normal in asthma between attacks.

• Peak Expiratory Flow Rate: reduced for expected value (for age, sex and height) and excessive diurnal variability of >10% in adults and >13% in children on twice daily measurement of PEFR
• CXR only to exclude complications of asthma (e.g., pneumothorax/pneumomediastinum, pneumonia) or other pathologies
• Stool analysis (to exclude helminths ova)

Beware of mimics of asthma

• Anaphylaxis reaction
• Heart failure causing cardiac asthma due to pulmonary edema
• COPD
• Helminthiasis (Loeffler syndrome)
• Upper-airway obstruction (stridor main feature)
• Vocal cord dysfunction syndrome (paradoxical adduction of vocal cords in inspiration in people with psychological stresses. Diagnosis is through direct laryngoscopy to confirm the paradoxical adduction of vocal cords during inspiration)

COMPLICATIONS OF ASTHMA

• Recurrent acute exacerbations (attacks).
• Pneumothorax/Pneumomediastinum/surgical emphysema (if in severe attack).
• Respiratory failure (in severe attack)
• Pneumonia risk