It may occur as an autosomal dominant trait in some families.
Clinical features:
(1) inhalatory stridor, which worsens when crying, feeding or during an upper respiratory tract infection (when respiratory effort increases) or when supine
(2) feeding problems
(3) signs of defective neuromuscular control may be present with:
(3a) gastric reflux
(3b) hypotonia
(3b) obstructive or central sleep apnea
Severe disease may feature:
(1) failure to thrive
(2) severe apnea
(3) cor pulmonale
(4) recurrent aspiration pneumonia
Diagnosis can be made with:
(1) flexible fiberoptic laryngoscopy
(2) direct laryngoscopy
(3) imaging studies
It may be necessary to exclude subglottic lesions (such as stenosis) if the child has severe findings, has unexpected findings or does not improve as expected.
The stridor may appear soon after birth or within a few weeks. Maximum stridor usually occurs around 6-9 months of age, after which symptoms tend to improve. In most children it resolves by 2-3 years of age.
