1 Chapter 99: Congenital Disorders of the Larynx ... - Famona Site

Severe stridor
Progressive stridor
Stridor associated with unusual features, such as cyanotic attacks, apneic attacks,
dysphagia, aspiration, failure to thrive, or a radiologic abnormality
Stridor causing undue parental anxiety.
Signs of obstruction
Airway obstruction may be present from birth and persistent, recurring with every
breath, as in bilateral vocal cord paralysis. It may also be variable and phasic, as in
laryngomalacia. Finally, it may be relentlessly progressive as with an enlarging cyst.
Major congenital airway obstruction in a newborn baby produces stridor, rapid
breathing with increased effort indicated by retraction of the chest, epigastric in-drawing,
tracheal tug, suprasternal and intercostal retraction, and flaring of the nasal alae during
inspiration. As obstruction progresses, even vigorous use of the accessory respiratory muscles
and tachypnea might not prevent respiratory failure with impaired pulmonary ventilation,
cyanosis, and subsequent bradycardia as the levels of hypoxia and hypercarbia increase.
With chronic airway obstruction, sternal retraction caused by persistent, negative
pleural pressure and high compliance of the rib cage may be exaggerated. With a longstanding
obstrucion, a permanent pectus excavatum may result.
In seriously ill patients with lower airway obstruction and lung parenchymal lesions
causing respiratory failure, blood-gas and blood-pH studies may be required as single or serial
examinations to assess the degree of respiratory failure and to assist in the management of
respiratory or metabolic acidosis. In patients with obstruction of the upper airways, blood
gases may remain normal or near normal even with severe obstruction. Clinical assessment
is much more important.
Cry abnormalities
Normal phonation depends not only on the subglottic air pressure but also on the
length, tension, and mass of the vibrating vocal cords and the ability of the straight free
medial margin of the vocal cord to vibrate freely. Any change in these variables produces an
abnormality of vocalization.
When both vocal cords are paralyzed, stridor always exists, and the cry, although
usually weak, is clear. With unilateral cord paralysis the cry may be weak and feeble, but
usually no serious ariway obstruction exists. Depending on the size of the laryngeal web,
complete aphonia or a weak, breathy, and feeble cry may exist; with smaller webs minimal
impairment of phonation may occur. A muffled or absent cry in infants may relate to
pharyngeal involvement, for example, from a cyst or other pharyngeal obstruction. Cysts in
or about the larynx affect the voice as well as obstruct the airway.
8