Laryngomalacia in infancy improves with increasing age irrespective of treatment

Citation:

MacLean JE. Laryngomalacia in infancy improves with increasing age irrespective of treatment. J Clin Sleep Med. 2021;17(4):619–620.

Laryngomalacia is the most common cause of stridor in infants though the overall prevalence of laryngomalacia is unknown.¹ It typically presents soon after birth or in the first weeks of life with inspiratory stridor that is worsened with activity, crying, and feeding. Both laryngeal tone and sensorimotor integrative function of the airway are altered resulting in dynamic prolapse of supraglottic tissue into the airway.² Despite its common occurrence, relatively little is known about the natural history of laryngomalacia.³ There appears to be a high rate of resolution without intervention (89–93%), based on resolution of stridor, and a broad time frame for this resolution (4–42 months). While some infants may benefit from surgical intervention, there is considerable debate on who are the infants with laryngomalacia who will benefit from supraglottoplasty.

Similar to laryngomalacia, the prevalence of obstructive sleep apnea (OSA) and central sleep apnea (CSA) is not known, and polysomnographic cutoffs to define OSA and CSA in infants are controversial. While the prevalence of OSA in children, excluding those < 1 year of age, is estimated to be 1% to 5%,⁴ applying the same polysomnographic cutoffs in infants would likely identify a higher prevalence of OSA for infants as compared to older children.⁵ The prevalence of CSA in both children and infants is unknown. Congenital airway abnormalities, including laryngomalacia, are important risk factors for OSA in infants. CSA occurring in the context of OSA in infants may resolve with treatment of OSA, as seen in older children.⁶

To address some of these gaps in our understanding, Ratanakorn and colleagues⁷ examine the overlap between OSA, CSA, and laryngomalacia, including the impact of treatment decisions, in this issue of the Journal of Clinical Sleep Medicine. This study reports on a large group of infants with laryngomalacia who underwent at least 2 polysomnograms and demonstrated central apnea index > 5 events/h or an obstructive apnea-hypopnea index or obstructive index > 1 event/h.⁷ Infants were grouped into those who underwent supraglottoplasty and those treated conservatively. The study highlights co-occurrence of laryngomalacia and OSA, the natural history of laryngomalacia in this subgroup, and the impact of supraglottoplasty for treatment. First off, OSA is common but isolated CSA is uncommon in infants with laryngomalacia, with 73% of infants demonstrating OSA or OSA/CSA while < 1% had CSA alone. While the cutoffs used to define OSA and CSA in this study likely overlap with parameters seen in otherwise healthy infants,⁸ there is still a lot of overlap between laryngomalacia and OSA. Second, similar to other conditions associated with airway obstruction in infancy, such as cleft palate⁹ and Robin sequence,¹⁰ airway obstruction in infants with laryngomalacia will improve with conservative management over the first 6 months of life. Last, in the broad group of infants with laryngomalacia, those undergoing supraglottoplasty had similar improvements in respiratory events and arousal index from 0–6 months of age to 6–12 months of age as those undergoing conservative treatment. Mean age at resolution of OSA also did not differ for those who underwent supraglottoplasty and those following conservative management. Like mandibular distraction for Robin sequence,¹¹ supraglottoplasty may have gained acceptance without a clear understanding of which infants will not improve with time alone. The results from this study suggest that in the absence of neurological disease, syndromes, or congenital anomalies, supraglottoplasty does not confer advantage over time alone.

It should be acknowledged that there is not agreement on the measures that should be used to identify and quantify the severity of laryngomalacia in infants. The International Pediatric Otolaryngology Group identified a list of frequently debated questions with respect to the evaluation of laryngomalacia.¹² While flexible fiberoptic laryngoscopy is used to identify laryngomalacia, classifications schemes for laryngomalacia have not been validated.³ Polysomnography can identify disruption in sleep parameters, respiratory events, and perturbation in oxygen and carbon dioxide levels but not the cause for these changes. Stridor, which is typically caregiver-reported, could be measured and quantified from sound recordings with methods applied to snoring and stertor.¹³ While it may not be too late to consider randomized trials of supraglottoplasty vs watchful waiting, the first step in designing such studies will require consensus on how to measure and quantify laryngomalacia in infants before and after treatment.

DISCLOSURE STATEMENT

The author has read and approved the final manuscript. Work for this commentary was performed at the University of Alberta. The author reports no conflicts of interest.