Vocal Cord Dysfunction / Inducible Laryngeal Obstruction (ILO) ✅

🗣️🫁 Vocal Cord Dysfunction / Inducible Laryngeal Obstruction - ILO is a disorder in which the larynx narrows inappropriately during breathing, usually on inspiration. It can cause sudden breathlessness, throat tightness, noisy breathing and sometimes voice change. It is often mistaken for asthma, but the obstruction is in the upper airway rather than the bronchi.

📖 About

• 🗣️ ILO describes transient, inappropriate, reversible narrowing of the larynx in response to triggers.
• 🎯 It may involve the true vocal cords, the supraglottic structures above them, or both.
• 🫁 It can occur alone or co-exist with asthma, chronic cough, reflux, breathing pattern disorder or anxiety-related symptom amplification.
• 🏃 Exercise-induced laryngeal obstruction - EILO is used when symptoms occur mainly during exertion.
• 📚 NICE asthma guidance includes ILO among the differentials for asthma-like breathlessness and inspiratory wheeze/stridor.

🧬 Pathophysiology

• 🚪 The larynx normally stays open during inspiration to allow airflow into the trachea.
• 🛡️ In ILO, the larynx behaves as though it is trying to protect the airway from an irritant or threat.
• 📉 This causes variable extrathoracic airflow obstruction, usually most obvious during inspiration.
• 🧠 The mechanism likely involves laryngeal hypersensitivity, altered sensorimotor control and trigger-induced protective closure.
• 💨 Because the problem is at throat level, bronchodilators often help little unless asthma also co-exists.

⚙️ Triggers and Associations

• 🏃 Exercise, especially high-intensity effort, is common in young people and athletes.
• 🌫️ Strong smells, perfumes, smoke, aerosols, dust, cold air and chemical irritants.
• 😂 Talking, laughing, shouting, yawning or taking a deep breath.
• 🔥 Reflux, throat clearing, mucus sensation, chronic cough or post-viral laryngeal irritation.
• 😰 Stress, panic or anxiety can amplify attacks, but symptoms should not be dismissed as “just psychological”.

🔎 Terminology

• 🗣️ Vocal cord dysfunction - VCD: older commonly used term.
• 🔁 Paradoxical vocal fold movement - PVFM: older descriptive term, especially when the true cords adduct during inspiration.
• 🫁 Inducible laryngeal obstruction - ILO: preferred modern umbrella term.
• 🏃 Exercise-induced laryngeal obstruction - EILO: used when symptoms are primarily exercise-related.

🩺 Clinical Features

• ⚡ Sudden breathlessness.
• 🗣️ Tightness in the throat rather than the chest.
• 🎵 Noisy breathing, often inspiratory; may be described as wheeze but may actually be stridor.
• ⬇️ Difficulty breathing in more than breathing out.
• 🗯️ Voice change, hoarseness, cough, choking sensation or inability to speak during severe episodes.
• ⏱️ Symptoms often come on rapidly and may settle quickly once the trigger is removed or breathing techniques are used.
• 💨 Repeated “asthma attacks” that do not respond well to inhalers.

🆚 ILO vs Asthma

🚨 Red Flags / Important Differentials

• 🫁 Acute severe asthma.
• 🚨 Anaphylaxis or angioedema.
• 🧸 Foreign body aspiration.
• 🔥 Epiglottitis or infective upper airway obstruction.
• 🧫 Laryngeal tumour or vocal cord palsy.
• 🚪 Tracheal stenosis.
• 🩸 Pulmonary embolism or other cardiopulmonary causes of dyspnoea.

🧪 Investigations

• 🗣️ Clinical history is crucial: trigger pattern, rapid onset/offset, throat symptoms and poor response to bronchodilators.
• 📈 Spirometry may be normal between attacks.
• 📉 Inspiratory loop flattening may suggest variable extrathoracic obstruction but is not sensitive enough to rule ILO in or out.
• 👃 Flexible nasendoscopy / laryngoscopy during symptoms is the diagnostic gold standard.
• 🏃 For exertional symptoms, provoked or continuous laryngoscopy during exercise may be required.
• 🫁 Investigate for co-existing asthma, reflux, chronic cough and breathing pattern disorder where relevant.

✅ Diagnosis

• ✅ Diagnosis is based on a compatible clinical history plus objective demonstration of inappropriate laryngeal narrowing where possible.
• 👃 Laryngoscopy during symptoms or provocation is the gold-standard diagnostic test.
• ⏱️ Because symptoms are intermittent, normal examination between episodes does not exclude ILO.
• 👥 A multidisciplinary approach is often helpful, involving respiratory medicine, ENT and speech and language therapy.

💊 Management

• 🤝 Reassure the patient that the condition is real, common and usually treatable.
• 🗣️ Speech and language therapy is the cornerstone of long-term treatment.
• 🧠 Education helps patients understand that the problem is upper airway closure, not dangerous “lung failure”.
• 🌬️ Teach laryngeal control / rescue breathing techniques.
• 🧘 Use relaxed throat and diaphragmatic breathing strategies.
• 🚫 Reduce throat clearing and maladaptive breathing patterns.
• 🎯 Use trigger identification, desensitisation and symptom self-management.
• 🔥 Treat contributory factors such as asthma, reflux, chronic rhinitis, chronic cough or breathing pattern disorder.
• 🧠 Psychological support may help when anxiety, panic, trauma or conditioned fear responses reinforce attacks.
• ⚠️ Avoid unnecessary escalation of asthma treatment if review suggests the dominant problem is upper airway obstruction rather than bronchospasm.

🚑 Acute Episode Management

• 🚨 Assess ABCDE and exclude life-threatening upper airway obstruction, anaphylaxis or true severe asthma.
• 🪑 Keep the patient calm, upright and coached.
• 🌬️ Use rescue strategies such as sniff in / blow out, relaxed nasal inspiration or pursed-lip exhalation.
• 🗣️ Use the patient’s established speech-therapy breathing technique if known.
• ⚠️ If there is diagnostic uncertainty, treat immediately dangerous differentials first.
• 🔍 Once stable, review whether the episode pattern fits ILO more than bronchospasm.

🏃 Exercise-Induced Laryngeal Obstruction - EILO

• 🏃 EILO is important in adolescents, young adults and athletes with exertional breathlessness.
• ⏱️ Symptoms often occur during peak exercise.
• 🫁 Exercise-induced bronchoconstriction more often peaks after exercise.
• 📹 Diagnosis may require continuous laryngoscopy during exercise or another provocation protocol that reproduces symptoms.
• 🎯 Breathing retraining and sport-specific trigger control can be very helpful.

📈 Prognosis

• ✅ Many patients improve substantially once the diagnosis is explained clearly.
• 🗣️ Speech and language therapy can reduce attack frequency and improve control.
• 🫁 Outcomes are best when co-existing asthma, chronic cough, reflux and dysfunctional breathing are recognised.
• ⚠️ Untreated ILO can lead to repeated emergency presentations, avoidable steroid exposure, exercise limitation and anxiety around breathing symptoms.

📌 OSCE / Exam Pearls

• 💡 Think of ILO when “asthma” presents with inspiratory noise + throat tightness + poor inhaler response.
• 💡 Difficulty breathing in points towards upper airway obstruction.
• 💡 Difficulty breathing out points more towards asthma.
• 💡 ILO and asthma can co-exist.
• 💡 The gold-standard investigation is laryngoscopy during symptoms or provocation.
• 💡 Speech and language therapy is the cornerstone of treatment.

📚 References

• UK consensus statement on the diagnosis of inducible laryngeal obstruction in light of the COVID-19 pandemic
• European Respiratory Society / European Laryngological Society statement: Inducible laryngeal obstruction
• Royal College of Speech and Language Therapists: Upper airway disorders within adult respiratory services
• British Thoracic Society: Clinical statement on assessment and management of respiratory problems in athletic individuals
• NICE CKS: Asthma - differential diagnosis.