xRead - February 2023

cry in infants. The mobile vocal fold may not be able to contact the immobile paramedian vocal fold to close the glottis and create a strong cry. In BVFP, the cry is usually stronger, because both vocal folds remain in close approx imation to each other at the cost of airway patency. Infants with VFP are at high risk for dysphagia including aspiration. Dysphagia can occur with both BVFP and UVFP, and no studies have demonstrated the differences in dys phagia between them. The overall incidence of dysphagia in infants with VFP is currently unknown. Dysphagia in infants with VFP after cardiac surgery has been reported to be as high as 93%. (35) The incidence of dysphagia is already high after neonatal cardiac repair even when VFP is not present, but VFP increases that risk of dysphagia. (23) Infants may present with comorbidities, which further affect the severity of the dysphagia, including but not limited to, congenital heart disease, bronchopulmonary dysplasia, intraventricular hemorrhage, laryngomalacia, and GERD. Clinical presentation of dysphagia may include coughing, choking, or changes in vocal quality during and after feed ing as well as frequent respiratory infections or aspiration pneumonia. However, dysphagia can present subtly in this population. Irace and colleagues reported that 57% of pedi atric patients with UVFP aspirated and all aspirated silently without overt signs of coughing. (44) History and Physical Examination A complete prenatal, intrapartum, and postnatal history should be obtained in patients with VFP, including if delivery was dif fi cult or required assistance. The surgical history should be evaluated to determine if any neck, cardiac, or thoracic surgeries have occurred that would have put the vagus or RLN at risk of injury. The clinician should assess the infant for signs and symptoms of dif fi culty breathing and feeding. A thorough physical examination with a focus on the head, neck, chest, and neurologic systems should be performed. The presence of congenital anomalies, low tone, or focal neurologic de fi cit may indicate the need to consult with certain specialists including neu rology, genetics, or pulmonology. All infants with persistent stridor or dysphonia should undergo an otolaryngology evaluation of the larynx. Laryngoscopy When VFP or another airway abnormality is suspected, the otolaryngologist will most likely perform laryngoscopy to con fi rm the diagnosis. Flexible laryngoscopy is the gold standard and is most commonly performed for diagnosis. EVALUATION

muscles mature, the paralysis may spontaneously resolve. (9) In general, idiopathic VFP has the highest incidence of spontaneous recovery and the bilateral cases may be more likely to resolve than unilateral cases. (9)

PATHOPHYSIOLOGY

The larynx is responsible for the complex balance between lower airway protection, swallowing, breathing, and voice production. Lower airway protection is the most primitive function of the larynx and requires coordinated closure of the vocal folds. A cough re fl ex, to expel material and prevent material from entering the lungs, also requires rapid clo sure of the vocal folds. Failure of an adequate cough function can contribute to pulmonary infection and respiratory com promise. Impaired laryngopharyngeal sensation can also impair airway protection re fl exes. In addition, complete closure of the vocal folds provides positive end-expiratory pressure to maintain adequate lung volumes and ventila tion. During normal breathing, the vocal folds open in a coordinated fashion and failure to open can restrict air movement. Air fl ow from the lungs passes up through intermittently closed vocal folds to produce voice and speech. Vocal fold movement is integral to all functions of the larynx. In VFP, the affected vocal fold(s) are usually immobile in the paramedian position, which can limit all functions of the larynx. Overall, stridor is the most common presenting symptom in infants with VFP. Of 102 pediatric patients, Daya and colleagues reported that stridor was present in 96% of BVFP cases and 77% of UVFP cases. (9) BVFP usually has more impressive respiratory symptoms and therefore tends to be identi fi ed at a younger age than UVFP. (8) Cyanosis, retractions, and apneas can also be present in patients with BVFP, but these symptoms are rare in patients with isolated UVFP. However, in UVFP, glottal incompe tence may be present and lead to pulmonary dysfunction that requires invasive and noninvasive respiratory support. (41) In a case-control study, infants with UVFP after PDA ligation had signi fi cantly longer durations of ventilator support, continuous positive pressure use, and oxygen use. (42) The possibility of VFP should be considered in any infant who cannot be weaned from invasive or noninvasive ventilation. In UVFP, the most common presenting symptoms are dysphonia, dysphagia, and respiratory symptoms, in that order. (43) Dysphonia presents as a hoarse, weak, or breathy CLINICAL PRESENTATION

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