Upper-airway obstruction and stridor — formative SAQs

SAQ 1 — The toddler with a barking cough (20 marks, ~15 minutes)

A previously well 2-year-old is brought to the emergency department at 2 am with a two-day coryzal prodrome and a sudden onset overnight of a barking, seal-like cough, a hoarse voice and inspiratory stridor that is worse when he cries. He is alert, pink, afebrile, drinking, and has mild intercostal recession with good air entry. Oxygen saturations are 98 percent in air. [1]

Questions

1. Give the most likely diagnosis and the typical causative organism, and state the two features that make a toxic airway emergency unlikely. (4 marks) [1]
2. Grade this child's severity, naming the score and its components. (4 marks) [1]
3. State your management for this child, with the specific drug and dose, and your management if he deteriorated to severe obstruction. (6 marks) [3]
4. State the evidence that supports treating even mild croup. (3 marks) [2]
5. State your disposition and the safety-netting advice you would give the family. (3 marks) [1]

Model answer (must-hit)

1. The most likely diagnosis is croup (laryngotracheobronchitis), most commonly caused by a parainfluenza virus. A toxic airway emergency such as epiglottitis is made unlikely by the absence of toxicity and drooling and by the child's ability to drink and to lie comfortably, together with the presence of the characteristic barking cough and hoarse voice, which are features of croup rather than supraglottic disease. [1]
2. Severity is graded with the Westley croup score, which uses five components: level of consciousness, cyanosis, air entry, stridor and retractions. This child has stridor only when upset, good air entry, no cyanosis, normal consciousness and mild retractions, giving a score below 3 — mild croup. [1]
3. Management of mild croup is a single dose of oral dexamethasone 0.15 to 0.6 mg/kg (commonly 0.15 mg/kg), keeping the child calm and undistressed, with observation until settled. If he deteriorated to severe obstruction (marked stridor at rest, reducing air entry, distress), I would give nebulised adrenaline 0.5 mL/kg of 1:1000 (maximum 5 mL) for rapid temporary relief, provide oxygen, involve senior and anaesthetic help, and observe for rebound as the adrenaline wears off at about two hours. [3] [4]
4. The randomised controlled trial of dexamethasone for mild croup and the Cochrane review of glucocorticoids for croup showed that corticosteroid reduces symptom severity and duration, return visits and the need for adrenaline and admission across all severities, including mild disease, which is why dexamethasone is given to essentially all children with croup. [2] [3]
5. A child with mild croup who is comfortable after dexamethasone can be discharged with clear safety-netting: croup fluctuates and is often worse at night; return if there is stridor at rest, increasing work of breathing, drowsiness, pallor or difficulty drinking. Keep the child calm at home. [1]

SAQ 2 — The toxic child with a threatened airway (20 marks, ~15 minutes)

A 4-year-old presents with a few hours of high fever, looking unwell, sitting forward, drooling and refusing to lie down, with a soft muffled voice, minimal cough and quiet inspiratory stridor. The parents are unsure whether his vaccinations are up to date. [6]

Questions

1. Give the two most important differential diagnoses and the mechanism of airway compromise. (4 marks) [6]
2. State the immediate do-not-distress principles and what you must NOT do. (5 marks) [6]
3. Outline how the airway should be secured. (5 marks) [6]
4. State the definitive treatment once the airway is safe, for each differential. (4 marks) [8]
5. State one feature that would point to bacterial tracheitis rather than epiglottitis. (2 marks) [8]

Model answer (must-hit)

1. The two most important differentials are epiglottitis (a toxic supraglottic infection, now rare after Hib vaccination but returning in under-immunised children) and a deep-neck infection such as a retropharyngeal abscess; bacterial tracheitis is also possible. The mechanism is progressive supraglottic or subglottic swelling and secretions narrowing a small airway, which can convert to complete obstruction if the child is distressed. [6]
2. The do-not-distress principle governs everything: keep the child calm on the carer's lap in the position of comfort, give oxygen only if tolerated without distress, and defer all upsetting procedures. Do NOT examine the throat with a spatula, do NOT lie the child flat, do NOT attempt intravenous cannulation or blood tests, and do NOT force a mask — any of these can precipitate complete obstruction. [6]
3. The airway is secured in a controlled environment: call the most senior available anaesthetist and ENT surgeon, move to theatre, and perform a gentle inhalational (gas) induction maintaining spontaneous ventilation, with the ENT surgeon scrubbed and ready to perform rigid bronchoscopy or a surgical airway if intubation fails. [6]
4. Once the airway is safe: epiglottitis is treated with intravenous third-generation cephalosporin, extubating within a few days as swelling settles; bacterial tracheitis needs airway endoscopy to clear purulent secretions and pseudomembranes plus intravenous antistaphylococcal and broad-spectrum antibiotics; a retropharyngeal abscess needs intravenous antibiotics and surgical drainage. [8]
5. Bacterial tracheitis is suggested by a preceding croup-like illness that worsens and fails to respond to nebulised adrenaline, with copious thick purulent tracheal secretions and pseudomembranes at endoscopy, rather than the cherry-red swollen epiglottis of epiglottitis. [8]