Acute asthma is one of the most common respiratory emergencies we encounter in paediatric practice, especially on the wards and in emergency settings. You can call this as a blog post is a overview of bedside-oriented discussion on acute asthma management, based on real-life clinical practice and aligned with established guidelines.
The aim is to keep things simple, systematic, and practical, while also highlighting important learning points and pitfalls through real clinical scenarios.
A Common Clinical Scenario
Let us start with a simple and typical example.
A seven-year-old boy, a known asthmatic, is on regular preventer and reliever therapy. He presents with:
Two days history of cough
No fever
Wheeze
Increasing breathing difficulty
Inability to speak in full sentences
This is a scenario all of us are familiar with. Before diving into detailed management, it is useful to have a snapshot approach—a quick overview of what needs to be done immediately. If you want a deeper understanding of the reasoning behind each step, it is important to go further into the details.
First Principles:
Assessment Comes First
The first and most important step in acute asthma management is assessment.
1. ABCD
A – Airway
B – Breathing
C – Circulation
D – Disability
This should not be a one-time assessment. It must be revisited repeatedly throughout management.
2. Assess Severity
Alongside ABCD, assess the severity of asthma. According to SIGN 158 guidelines (UK), acute asthma is classified into:
Moderate acute asthma
Acute severe asthma
Life-threatening asthma
It is important to remember that acute asthma has limitations in both clinical assessment and investigations. Clinical signs do not always correlate well with the degree of airway obstruction.
Important Clinical Caveats
Some children may not look as unwell as they actually are.
Younger children may not show classical signs despite severe disease.
Clinical signs that correlate poorly with severity include:
Degree of wheeze
Pulsus paradoxus
Respiratory rate
Because of this, systematic assessment and frequent reassessment are crucial.
Core Management Principles
1. Treat Hypoxia Early
If a child is in respiratory distress:
Start oxygen immediately
Do not wait for oxygen saturations to fall
Even children with “normal” saturations may still be hypoxic and struggling
2. Treat Bronchospasm and Inflammation
Acute asthma management revolves around:
Bronchodilation
Anti-inflammatory therapy
At the same time, always think about:
Possible trigger factors
Differential diagnoses
2. Bronchodilators
Salbutamol /Albuterol (β₂-agonist)
Salbutamol is the first-line bronchodilator.
β₂-agonist work by causing bronchial smooth muscle relaxation
Routes of administration:
Inhalation (via spacer or nebuliser)
Intravenous infusion
Subcutaneous injection
Doses (always double-check locally):
Inhaler: 100 micrograms per puff, usually 6–10 puffs as needed
Nebulised:
< 5 years: 2.5 mg
≥ 5 years: 5 mg
IV infusion: 1–5 micrograms/kg/min
Important side effects:
Tachycardia
Tremors
Hypokalaemia
Raised lactate
Rarely, allergy to salbutamol (I have personally seen this)
Ipratropium Bromide
Ipratropium is the second bronchodilator, often used in combination with salbutamol.
Mechanism of action:
Acetylcholine receptor antagonist
Reduces cyclic GMP
Different mechanism from salbutamol → synergistic effect
Use:
Inhaler via spacer or nebulised
Recommended only in the acute phase
Should be stopped later, continuing salbutamol alone.
Important caution:
Can cause paradoxical bronchospasm
Steroids: Treating Inflammation
Steroids MUST be given early.
Options include:
Oral prednisolone (if child can tolerate oral medication)
Dexamethasone
IV hydrocortisone (if oral route not possible)
Magnesium Sulphate
Magnesium sulphate is an important and interesting medication in acute asthma.
I have seen patients dramatically improve with magnesium, although not all respond. Literature shows variable efficacy, but:
Most major guidelines (GINA, NICE, SIGN) recommend its use in acute severe asthma.
Routes:
Nebulised
Intravenous infusion
Both can be used in the same patient
Dose:
IV: 40 mg/kg over 20 minutes (maximum 2 g)
Nebulised: 150 mg
Side effects to remember:
Hypotension
Arrhythmias
Hypermagnesaemia
Because of these risks, children receiving magnesium require at least a high-dependency level of monitoring.
Key point:
If you are at the stage of giving magnesium sulphate, you should already be preparing for aminophylline, as escalation takes time.
Aminophylline
Aminophylline has been used for many years but has limitations.
Actions:
Bronchial smooth muscle relaxation
Improves diaphragmatic and skeletal muscle contractility
Central nervous system stimulation
Limitations:
Poor efficacy compared to newer agents
Significant side effects
Important side effects (all of which I have seen):
Hypotension
Arrhythmias
Vomiting
Convulsions
It should be used cautiously and with appropriate monitoring.
High-Flow Nasal Cannula (HFNC) Oxygen
High-flow nasal cannula therapy is increasingly used and likely to become more common.
Benefits:
Supports work of breathing
Useful in children with severe respiratory distress, including asthma
Limitations:
Some anxiety or discomfort
Overall, well tolerated in most cases
This is an evolving area, and we are likely to see more evidence and wider use in future practice.
Adrenaline (Epinephrine)
If a child has severe asthma, no response to standard therapies, and no additional help is available, there is no harm in considering adrenaline.
Historically:
Adrenaline was one of the main drugs of choice
Used subcutaneously in repeated doses (every 30 minutes)
It still has a role in selected, severe cases.
The Importance of Reassessment
Revisit and reassessment are crucial in all acute management, including asthma.
Key steps to revisit:
ABCD assessment
Severity classification
Oxygen therapy
Response to bronchodilators and steroids
Need for escalation (magnesium, aminophylline, HFNC)
Role of Investigations
Investigations have a limited role in acute severe asthma.
Blood Tests and Blood Gases
Poor correlation with clinical condition
Use only if clinically indicated or if another diagnosis is suspected
Chest X-ray
Indicated if:
Severe respiratory distress
Suspected pneumothorax
Suspected infection
Learning from Clinical Cases
Case 1: When It Was Not Asthma
A 4.5-year-old boy with recurrent wheeze on montelukast presented with:
Fever
Cough
Breathing difficulty
He was treated as asthma, but after 1–1.5 hours, there was no improvement. On reassessment:
Focal signs
Reduced air entry on one side
A chest X-ray - pyo-pneumothorax.
Case 2: Asthma or Anaphylaxis?
Another child with known asthma presented with:
Sudden onset breathing difficulty
No preceding symptoms
No response to standard asthma treatment
On reviewing medications, the grandmother revealed an EpiPen—the child was nut allergic.
This was an allergic reaction, not asthma. After giving adrenaline, the child improved dramatically.
Lesson:
Always reconsider the diagnosis and check for alternative explanations.
Key Take-Home Messages
Acute asthma is common but can be deceptive
Always start with ABCD assessment
Treat hypoxia early
Use bronchodilators and steroids promptly
Escalate systematically: magnesium → aminophylline → respiratory support
Investigations have limited but targeted roles
Reassessment is critical
Learn from clinical cases—they are powerful teachers
Like ABCD in management, at every step of management we should be ready for Plan B, C and ...
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