Exercise-induced bronchoconstriction — branching viva

Station opening

Examiner: "Define exercise-induced bronchoconstriction and explain how it relates to asthma." [3]

Strong candidate (must-hit)

• Defines exercise-induced bronchoconstriction as transient narrowing of the lower airways provoked by exercise, coming on during or after effort, peaking five to fifteen minutes after it stops, and resolving within thirty to sixty minutes; explains that it is a physiological event, not a disease of its own; states that in most children it occurs as part of asthma and marks inadequate control, while a minority have isolated disease without other asthma features. [3] [5]

Weak candidate

• "It's just asthma that comes on when you run, so you give a blue inhaler." [3]

Branch A — Confirming the diagnosis

Examiner: "An 8-year-old coughs and wheezes after running. How would you confirm the diagnosis, and what would you make of a normal resting spirometry?" [10]

Strong

• Recognises the classic after-exercise pattern; states that the diagnosis is confirmed objectively with a standardised exercise challenge or eucapnic voluntary hyperpnoea (or an indirect mannitol challenge) showing a fall in FEV1 of ten percent or more from baseline, taken as the maximum fall over serial measurements; explains that a normal resting spirometry does not exclude the diagnosis because the airway is open between episodes, so the value lies in the provocation. [10] [3]

Weak

• "If the spirometry today is normal then there's nothing wrong." [10]

Branch B — The mechanism

Examiner: "Explain to me how exercise actually narrows the airway." [2]

Strong

• Explains that exercise hyperpnoea delivers large volumes of cold dry air to the lower airway, bypassing nasal conditioning and dehydrating the airway surface liquid; states the osmotic hypothesis that the resulting hyperosmolarity activates mast cells to release histamine, cysteinyl leukotrienes and prostaglandin D2, contracting smooth muscle and producing oedema and mucus; adds the contributing thermal or vascular mechanism of airway cooling then rewarming; and explains the refractory period that a warm-up exploits. [2] [5]

Weak

• "The cold air just irritates the lungs." [2]

Branch C — Management and the athlete

Examiner: "A 15-year-old with confirmed exercise-induced bronchoconstriction wants to keep competing. What is your management?" [12]

Strong

• States that the first and most important step is to control any underlying asthma with a regular inhaled corticosteroid, checking adherence and technique; adds the non-drug measures (warm-up, warming inspired air, avoiding cold dry and polluted conditions); prescribes a pre-exercise short-acting beta-agonist while warning that daily use causes tolerance; escalates to a leukotriene antagonist or ICS with a long-acting beta-agonist (never LABA alone) for persistent symptoms; notes anti-doping documentation and environmental exposures as athlete-specific issues; and sets full participation in sport as the goal. [12] [8]

Weak

• "Just give her a long-acting bronchodilator on its own before she runs." [8]

Branch D — The breathlessness that does not respond

Examiner: "A runner is breathless at maximal effort with a tight throat and noisy breathing in, which clears the moment she stops and does not respond to salbutamol. Her exercise challenge is normal. What is going on?" [3]

Strong

• Recognises inducible laryngeal obstruction (vocal cord dysfunction): inspiratory stridor and throat tightness at peak effort, clearing within a minute or two without a bronchodilator, with a normal exercise challenge refuting airway bronchoconstriction; states that the diagnosis is confirmed ideally by continuous laryngoscopy during exercise; and manages with breathing retraining and speech therapy rather than escalating asthma treatment. [3] [10]

Weak

• "Increase the inhaled steroid and add another reliever." [3]

Station close

Examiner: "Summarise the goal of managing exercise-induced bronchoconstriction in one sentence." [12]

Strong

• "The goal is full, unrestricted participation in exercise and sport, achieved by confirming the diagnosis objectively, excluding the mimics, controlling the underlying asthma first, and adding a warm-up, inspired-air conditioning and a pre-exercise reliever while avoiding daily short-acting beta-agonist tolerance." [12] [5]