Congenital laryngeal stridor (laryngomalacia): etiologic factors and associated disorders.

Congenital laryngeal stridor (CLS) and laryngomalacia are terms used to describe a common disorder characterized by onset, at or soon after birth, of a harsh respiratory sound mostly audible during inspiration. Typically, laryngoscopy reveals flaccid supraglottic structures which tend to prolapse medially toward the glottis during inspiration. Despite reports of this disorder dating back to the mid-19th century, specific etiology and pathogenesis remain nebulous. Analysis of findings in 30 infants indicate that there are often associated manifestations of delayed development in neuromuscular control. Associated findings include gastroesophageal reflux, obstructive and central apnea, hypotonia, failure to thrive, and pneumonitis. A retrospective review of relevant medical literature along with results of laryngeal dissections and analysis of clinical findings in the 30 cases leads to the conclusion that CLS may be a mild form of localized hypotonia rather than an isolated idiopathic type of anatomic abnormality.