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Respiratory System

Asthma

A chronic inflammatory disease of the airways characterized by reversible airflow obstruction, leading to recurrent episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night or early morning. Acute attacks (exacerbations) can be triggered by various factors.

Also known as: Wheezing, Reactive Airway Disease

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Referral and warning signs

When to refer

Refer to higher level/specialist for: Difficulty confirming diagnosis. Poor symptom control despite Step 3/4 therapy. Frequent exacerbations requiring oral steroids. Severe or life-threatening exacerbation. Need for specialist therapies (e.g., biologics). Children <5 years with moderate persistent asthma (Step 3).

Red flags

  • Signs of severe/life-threatening attack (silent chest, cyanosis, confusion, exhaustion, inability to speak, PEF <50% or <33%)
  • Poor response to initial reliever therapy
  • History of previous life-threatening attacks or ICU admission for asthma

Signs and symptoms

  • Recurrent wheezing
  • Cough (often dry, worse at night)
  • Breathlessness / Difficulty breathing
  • Chest tightness
  • Symptoms often worse at night or with triggers (exercise, cold air, allergens, URTI)
  • Acute Attack (Mild/Moderate): Able to talk in sentences/phrases, PEF >50%, RR/Pulse elevated but within moderate ranges, SpO2 ≥92%.
  • Acute Attack (Severe): Cannot complete sentences, breathless at rest/feeding, uses accessory muscles, PEF <50%, RR/Pulse significantly elevated, SpO2 <92%.
  • Acute Attack (Life-threatening): Silent chest, feeble respiratory effort, cyanosis, exhaustion, confusion, bradycardia, hypotension, PEF <33%, SpO2 <92%.

Risk factors

  • Personal or family history of asthma or allergies (atopy)
  • Exposure to allergens (dust mites, pollen, animal dander, mould)
  • Exposure to irritants (tobacco smoke, pollution, occupational dust/chemicals)
  • Viral respiratory infections (common trigger for exacerbations)
  • Exercise
  • Cold air
  • Certain medications (e.g., Beta-blockers, NSAIDs/Aspirin in some individuals)

Diagnosis

Clinical assessment

Diagnosis is primarily clinical, based on pattern of recurrent respiratory symptoms (wheeze, cough, dyspnoea, chest tightness) and response to bronchodilator therapy. Assess severity based on symptoms frequency, night waking, activity limitation, and reliever use. Acute attack severity assessed using clinical signs, PEF, SpO2. Differential diagnosis: Heart failure, COPD, Bronchiolitis (infants), Bronchiectasis, Foreign body aspiration, Upper airway obstruction.

Investigations

  • Peak Expiratory Flow Rate (PEFR): Measurement at baseline and post-bronchodilator (>15-20% improvement suggests reversibility). Used for monitoring.
  • Spirometry: Shows obstructive pattern (reduced FEV1/FVC ratio) with significant reversibility (>12% and 200ml increase in FEV1) after bronchodilator. Gold standard for diagnosis.
  • Sputum Eosinophilia (less common).
  • Allergy testing (if identifying triggers needed).
  • Chest X-ray: Usually normal, used to exclude other diagnoses (e.g., pneumonia) during exacerbations.

Diagnostic criteria

Clinical pattern of episodic/variable respiratory symptoms suggestive of asthma, often confirmed by demonstrating reversible airflow obstruction (spirometry or PEFR response to bronchodilator).

Management

Non-pharmacological management

  • Patient Education: Understanding asthma, trigger avoidance, correct inhaler technique, action plan.
  • Trigger Avoidance: Identify and avoid specific allergens/irritants.
  • Smoking Cessation (patient and household).
  • Monitoring: Symptom diary, PEFR monitoring (optional for some).
  • Asthma Action Plan: Written plan for self-management, including adjusting medication and when to seek help.
  • Acute Attack: Reassurance, sit patient upright.

Pharmacological treatment

  • General Principles: Stepwise approach based on symptom control. Inhaled route preferred. Use spacers for children/poor technique.
  • Reliever Therapy (For symptom relief): Short-Acting Beta2-Agonists (SABA) - e.g., Salbutamol inhaler 100-200mcg (1-2 puffs) PRN.
  • Controller Therapy (Regular prevention - based on severity step):
  • - Step 1 (Intermittent): SABA PRN only.
  • - Step 2 (Mild Persistent): Low-dose Inhaled Corticosteroid (ICS) - e.g., Beclomethasone 100-200mcg BID. Plus SABA PRN.
  • - Step 3 (Moderate Persistent): Low-dose ICS + Long-Acting Beta2-Agonist (LABA) - e.g., Salmeterol/Fluticasone or Budesonide/Formoterol combination inhaler OR Medium/High-dose ICS. Plus SABA PRN. (UCG suggests high-dose ICS first). Consider adding Aminophylline 200mg BID (adults - less preferred now).
  • - Step 4 (Severe Persistent): High-dose ICS + LABA +/- other controllers (e.g., LTRA, Theophylline, Tiotropium). Consider regular low-dose oral Prednisolone (specialist). Plus SABA PRN.
  • Acute Asthma Attack Management:
  • - Mild/Moderate (Outpatient/HC3): Salbutamol inhaler (via spacer) 2-10 puffs OR Nebulized Salbutamol 2.5-5mg. Repeat Q20-30min PRN for 1 hour. Oral Prednisolone 1mg/kg (max 50mg) daily for 3-5 days.
  • - Severe (Referral/HC4/Hospital): Oxygen (aim SpO2 >94%). High-dose Salbutamol (nebulized or MDI+spacer, repeated frequently). Add Ipratropium Bromide nebulized (250-500mcg) Q20-30min initially. Systemic Corticosteroids (Oral Prednisolone or IV Hydrocortisone 100mg Q6H). Consider IV Aminophylline (loading + infusion - use with caution, specialist input).
  • - Life-Threatening (Hospital/ICU): As for Severe, plus consider IV Magnesium Sulphate, potential need for intubation/ventilation.
  • Rescue Course Oral Steroids: Short course (3-5 days) of Prednisolone can be used at any step for exacerbations.

Monitoring

  • Symptom control (daytime, nighttime, reliever use frequency, activity limitation).
  • Frequency of exacerbations.
  • PEFR (if used).
  • Inhaler technique and adherence.
  • Side effects of medications.
  • Regular review (e.g., every 3-6 months when stable) to assess control and step up/down therapy.

Complications

  • Severe/life-threatening exacerbations
  • Respiratory failure
  • Status asthmaticus
  • Pneumothorax (rare)
  • Airway remodelling (long-term uncontrolled asthma)
  • Side effects of medications (ICS: oral thrush, dysphonia; Systemic steroids: Cushingoid features, osteoporosis, diabetes, etc.)

Prevention

  • Trigger avoidance
  • Adherence to controller medications
  • Smoking cessation
  • Influenza vaccination

Patient education

  • Nature of asthma as chronic inflammatory disease.
  • Difference between reliever and controller inhalers.
  • Correct inhaler technique (demonstration, check).
  • Use of spacer devices.
  • Trigger identification and avoidance.
  • Importance of adherence to controller medication.
  • Written asthma action plan.
  • Recognizing worsening asthma and when to seek urgent help.
  • How to manage mild exacerbations at home ('rescue' steroids).

Uganda-specific notes

Diagnosis often clinical due to limited spirometry. Inhaled Salbutamol and Beclomethasone are key medications. Spacer devices crucial for children. Oral steroids used for exacerbations. Aminophylline use discouraged but may be used if other options limited. Trigger avoidance important (dust, smoke).

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 5, Section 5.1.1 (Acute & Chronic)

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