Is Inducible Laryngeal Obstruction (ILO) considered part of the spectrum of functional breathing disorders?

Inducible Laryngeal Obstruction as Part of Functional Breathing Disorders

Yes, Inducible Laryngeal Obstruction (ILO) is considered part of the spectrum of functional breathing disorders, though it has distinct diagnostic criteria and management approaches that differentiate it within this broader category.

Understanding ILO Within Functional Breathing Disorders

ILO is defined as an inappropriate, temporary narrowing of the larynx causing breathing problems that are typically trigger-induced and reversible 1. This condition fits within the broader concept of functional breathing disorders for several key reasons:

• ILO often co-exists with breathing pattern disorders (BPD), which are alterations in normal biomechanical patterns of breathing 2
• Both conditions can present with similar symptoms of dysfunctional breathing
• They frequently share management approaches, particularly breathing retraining techniques

Diagnostic Distinction

The 2013 international consensus conference on ILO nomenclature specifically addressed terminology issues, rejecting terms like "factitious," "hysterical," and "functional" for the umbrella definition because:

• These terms assume a psychogenic basis
• Not all ILO cases have psychogenic causes
• Such terminology may have negative connotations in different languages 3

Instead, the term "inducible" was chosen to describe the attack-like/varying nature of the condition, acknowledging that underlying mechanisms exist without assuming causation 3.

Clinical Relationship Between ILO and Functional Breathing

The relationship between ILO and functional breathing disorders is supported by:

1. Common multidisciplinary management approach:

   • Both conditions benefit from physiotherapy, speech therapy, and psychological interventions 2
   • Treatment involves similar breathing retraining techniques

2. Co-occurrence:

   • ILO and breathing pattern disorders frequently co-exist 4
   • They can be viewed as separate components under the overarching term "dysfunctional breathing" 4

3. Shared triggers and comorbidities:

   • Both can be triggered by exercise, stress, or irritants
   • Both frequently coexist with conditions like asthma, reflux, and anxiety 2, 4

Diagnostic Framework

For proper diagnosis of ILO within the functional breathing disorder spectrum:

• Videolaryngoscopy during symptom provocation is the gold standard for ILO diagnosis 1, 5
• Breathing pattern analysis helps identify associated breathing pattern disorders 4
• Proper classification requires identification of:
  • Inducer (trigger)
  • Laryngoscopic findings 1

Management Implications

Understanding ILO as part of functional breathing disorders impacts treatment:

• Immediate management focuses on:

  • Removal from trigger exposure
  • Specialized breathing techniques
  • Positioning and reassurance 1

• Long-term management requires:

  • Coordinated care between pulmonology, otolaryngology, and speech pathology
  • Psychological support when anxiety/stress are factors
  • Treatment of comorbidities before addressing ILO directly 4

Important Clinical Distinctions

While ILO is part of functional breathing disorders, it must be distinguished from:

• Constant laryngeal obstructions (not inducible)
• Laryngeal spasm (physiological response to sensory stimulation)
• Expiratory vocal fold closure in asthma (compensatory mechanism) 3

These distinctions are crucial as they directly impact treatment approaches and patient outcomes.

Conclusion

While terminology has evolved to avoid psychogenic assumptions, the clinical evidence clearly positions ILO within the spectrum of functional breathing disorders, with important diagnostic and therapeutic implications for clinical practice.