History and exam
Key diagnostic factors
common
presence of risk factors
stridor
Parents report an audible respiratory noise and may have noted that it is present during inspiration. It is present intermittently and is variable in intensity. The loudness of the stridor does not correlate with clinical severity. It worsens with crying, activity, lying supine, or feeding. It may be lessened with prone positioning or chin lift/jaw thrust.
The noise becomes apparent within 2 weeks of birth and may increase in intensity/frequency until 6 to 8 months of age. It gradually resolves of its own accord, usually before 2 years of age.
A neurological variant may persist beyond this age in children with reduced laryngeal tone: for example, those with cerebral palsy.
onset within 2 weeks of birth
Reported symptoms, including inspiratory stridor and airway obstruction, typically first become apparent in the first 2 weeks of life.
These symptoms are usually not present at birth, which helps to differentiate LM from conditions that typically present with airway obstruction from birth (e.g., vocal cord palsy, congenital subglottic stenosis, and vallecular cysts).
features of airway obstruction
Clinical features include nasal flaring; suprasternal, intercostal, or subcostal recession; abdominal respiration; and tracheal tug. Sternal recession and/or pectus excavatum may be present.
Despite the obstruction, patients usually seem comfortable, are systemically well, and are not in acute respiratory distress unless there is an additional factor further exacerbating their obstruction. Patients are usually well oxygenated.
Cyanosis occurs extremely rarely, and if present should raise suspicion of alternative diagnoses.
resolution of symptoms by 2 years of age
Natural progression of the condition sees a gradual increase in the symptoms, until the child is 6 to 8 months of age, although this timeframe is somewhat variable. There is then a gradual, spontaneous improvement with 70% resolving by 12 months of age.[22] Complete resolution occurs in most cases before the age of 2 years.
normal cry
In LM, cry is typically normal. This serves to differentiate from other laryngeal conditions where abnormal or absent cry is a feature (vocal cord palsy, laryngeal web).
Other diagnostic factors
common
feeding difficulties
Infants feed very slowly or develop increased respiratory noise or airway obstruction during the feed, thus limiting intake. There may be associated episodes of coughing or choking during the feed. The infant may seem to 'run out of breath' during the feed. There may also be previously diagnosed episodes of aspiration.
These problems may lead to either poor weight gain or loss of weight. In severe cases, there is failure to thrive if the child is taking insufficient nutrients for normal growth.
Symptoms are compounded by the frequent co-existence of GORD. Laryngeal penetration with aspiration beyond the vocal folds has been found in 72% of infants with severe LM.[29]
uncommon
weight loss or failure to thrive
Feeding difficulties occur commonly with associated poor weight gain, weight loss, or failure to thrive in severe cases.
The overall size of the child should be considered relative to their age. Poor weight gain may not always be immediately apparent. Useful information can be gained if serial weights are plotted on a centile growth chart to determine if the child is falling behind in expected growth for age.
Monitoring of weight gain is particularly useful for cases of moderate severity where surgical intervention is being considered. Pre- and postoperative measurement of growth velocity may also be used to objectively determine improvement following supraglottoplasty.[30]
hypotonia
17% to 47% of patients with severe LM have been reported to have additional associated conditions or syndromes.[7][8] These include Down's syndrome and, less commonly, syndromic congenital cardiac disease.[19][20] Neurological-variant laryngomalacia is seen in association with neurological pathology, including generalised or focal hypotonia, and cerebral palsy. These children often exhibit a somewhat atypical form, which does not tend to spontaneously resolve and has been shown to be associated with poorer long-term outcomes following surgical treatment.
dysmorphic features
Data suggest that LM is more common in patients with an underlying genetic syndromic disorder. These include Down's syndrome and, less commonly, syndromic congenital cardiac disease.[19][20]
Dysmorphic features of Down's syndrome include up-slanting palpebral fissures, bilateral epicanthal folds, nasal hypoplasia, and dental abnormalities.
Risk factors
strong
GORD
GORD is reported in 50% to 100% of patients with laryngomalacia (LM).[1][7][14][15][16]
It has been proposed that reflux causes laryngeal mucosal inflammation and oedema, with narrowing and increased obstruction leading to LM. This in turn increases negative intrathoracic pressure, which exacerbates GORD.[17]
A systematic review has confirmed the co-existence of reflux and LM but was unable to establish a definite causal relationship.[18] Nevertheless, clinical experience shows that anti-reflux therapy may improve LM, and supraglottoplasty can improve reflux.
neurological abnormalities
Reported in up to 20% of patients with LM.[14]
Neuromuscular incoordination or hypotonia possibly arising from immaturity of the neural pathways, may contribute to poor supralaryngeal tone.[12][13][14]
A neurological-variant laryngomalacia in association with generalised or focal hypotonia, and cerebral palsy, is often atypical and does not tend to spontaneously resolve. It has been shown to be associated with poorer long-term outcome following surgical treatment.
laryngeal anatomical abnormalities
Abnormalities in supraglottic anatomy may predispose to LM.[11] For example, some patients have anatomical features (e.g., short aryepiglottic folds, curled 'omega-shaped' epiglottis) that contribute to the dynamic supraglottic narrowing.
male sex
LM occurs in almost twice as many males as females.[10]
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