VCP is the second most common congenital abnormality of the larynx and is responsible for 10% of all congenital airway lesions (Hollinger, Holinger,
& Holinger, 1976). VCP occurs secondary to the dysfunction of the nerve supply to the laryngeal muscles, which differs from VFI (often called vocal cord immobility), which is defined as both paralysis and fixation.
Additionally, unilateral VCP differs from bilateral VCP in presentation, etiology, and treatment (Chen & Inglis, 2008).
Epidemiology
Bilateral VCP occurs in 30–62% of all cases of VCP, with spontaneous recovery in 48–62% of these cases (Brigger & Hartnick, 2002). Incidence of bilateral VFI is still low overall with reported estimates at 0.75 cases per million births per year (Murty, Shinkwin, & Gibbin, 1994). When looking specifically at reports of unilateral VFI, research is varied. Two reports found in the literature document rates of 8 and 25% (Cavanaugh, 1955;
Schild & Holinger, 1980).
Pathophysiology
Children differ from adults in their causes of bilateral VCP. VCP may occur secondary to the stretching and compression of the vagus nerve or the stretching or compression of the recurrent laryngeal nerves (Chen & Inglis, 2008). The causes of nerve injury may be neurological, traumatic, iatro- genic, or idiopathic.
Twenty-five to thirty percent of VCP is from a neurological cause. One of the most common neurological causes is secondary to Arnold–Chiari malformation with associated myelomeningocele and hydrocephalus. It is thought that the vagus nerve becomes stretched and compressed by the protrusion of the cerebellar tonsils, medulla, and brain stem through the foramen magnum (Chen & Inglis, 2008). With this lesion, the infant or child will usually have bilateral paralysis; however, unilateral paralysis has also been reported. Other less common central nervous system lesions include encephalocele, leukodystrophy, hydrocephalus, and cerebral or nuclear dysgenesis. Amyotrophic lateral sclerosis (ALS) may present in the older child and may cause unilateral or bilateral vocal cord involvement. Perinatal hypoxia or cortical stroke is a rare cause (Jong, Kuppersmith, Sulek, &
Friedman, 2000). Muscular dystrophies and peripheral neuromuscular dis- orders have been reported. Examples include myasthenia gravis, myotonic dystrophy, and Charcot–Marie–Tooth disease.
A traumatic cause may be birth trauma. This is secondary to breech presentation, use of forceps for delivery, or intubation, which can cause
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stretching or compression of one or both recurrent laryngeal nerves of the neck.
The most common iatrogenic cause is secondary to surgery, including patent ductus arteriosis ligation and repair of tracheoesophageal fistula.
Paralysis may occur unilaterally or bilaterally. If unilateral, left VCP is more common, secondary to the longer course of the left recurrent laryngeal nerve. Other cardiac surgeries implicated as causes of VCP include those for tetralogy of Fallot and ventricular septal defect. Vascular rings, aortic arch abnormalities, and patent ductus arteriosis surgeries are more typical for laryngeal paralysis (Jong et al., 2000).
Examples of idiopathic etiologies may include infectious, rheumato- logic, or mitochondrial disorders (Rubin & Sataloff, 2007). Most of the infectious etiologies of the past, including poliomyelitis and tetanus, are rare today secondary to immunization. Guillian Barre is still a reported cause.
Signs and symptoms
The most common presenting symptom of bilateral VCP is stridor, which is typically biphasic. Infants will usually have a loud cry. Because the vocal cords are often paralyzed in the paramedian position (abductor paralysis), the voice or cry can be normal. Of note, infants are more likely to present with stridor and dyspnea than with dysphonia or aspiration (Chen &
Inglis, 2008). If the cords are paralyzed medially, severe respiratory failure occurs.
Infants with unilateral VCP may present with stridor, or a weak cry (Parikh, 2004). If there is stridor, it will usually be on inspiration, whereas with bilateral paralysis, it is typically biphasic. Symptoms may vary depending on whether the vocal cord is in the paramedian or median posi- tion. If the unilateral cord is immobile in the paramedian position, then there is a lack of opposition of the cord and the child may have a weak cry or voice. Over time, the other cord compensates and the child may achieve a more normal voice with time. Feeding difficulties may be present second- ary to aspiration or an inability to coordinate the swallow secondary to an incompetent larynx. If there are no feeding or airway problems, the diag- nosis may go undetected (Parikh, 2004). Older children and adolescents may present similar to adult patients with a soft or breathy voice distur- bances or may have symptoms of dysphagia.
Diagnosis
A full head and neck exam is essential to evaluate for anatomical abnor- malities, masses, and/or cranial nerve abnormalities. The child should also be evaluated for any breathing difficulties with particular attention to work of breathing and timing of abnormal respiratory sounds, such as stridor. If suspicion is high for an airway abnormality, then initial consultation of the infant or child with stridor includes airway evaluation with bedside fiber- optic laryngoscopy by an otolaryngologist.
144 Nursing Care in Pediatric Respiratory Disease
At times, there may be difficulties determining if the VFI is bilateral or unilateral secondary to a crying infant or a limited view of the vocal folds.
A confirmatory exam and full evaluation may ultimately be completed by direct laryngoscopy and bronchoscopy in the operating room. The advan- tage of intraoperative evaluation is the ability to fully evaluate the child for secondary abnormalities such as laryngeal cleft or subglottic stenosis.
Imaging studies such as CT scan or ultrasound are not the standard of care but have been used as diagnostic studies. The utility of the study depends on suspicion of extrinsic lesions or other abnormalities such as central nervous system lesions.
Management
Management differs for bilateral and unilateral VCP. For most cases of bilateral VCP, a tracheostomy will be performed either as a temporary or permanent measure to secure and protect the child’s airway. If the cause is thought to be temporary, the child may remain intubated or under close observation, and tracheostomy may be deferred while awaiting spontane- ous recovery.
Depending on the etiology, serial airway exams may be performed to evaluate the infant or child for resolution. Neurological and idiopathic causes have the best chance of spontaneous recovery, which, if it occurs, will generally happen in the first 6 months but can occur up to 11 years after diagnosis (Daya, Hosni, Bejar-Solar, Evans, & Bailey, 2000). For this reason, many otolaryngologists will wait before intervening surgically.
Moreover, for infants less than 6 months, treating the underlying cause, such as Arnold–Chiari malformation abnormalities or hydrocephalus, by placement of a ventriculoperitoneal shunt may resolve the paralysis in up to 62% of the cases (Parikh, 2004).
For long-term VCP in children, various surgical techniques such as suture lateralization, arytenoidectomy, cordectomy, and posterior cricoid split with cartilage graft have been described in the literature. Outcome measures include rates of decannulation, which may vary. Some of the risks with surgery include voice disturbances, airway issues, and swallow- ing dysfunction (Bower, Choi, & Cotton, 1994; Gupta, Mann, & Nagarkar, 1997; Hartnick, Brigger, Willging, Cotton, & Myer, 2003; Inglis et al., 2003;
Mathur, Kumar, & Bothra, 2004). There is also a theoretical concern of the effect on laryngeal growth (Parikh, 2004).
In most cases of unilateral VCP, the child will not require any airway intervention. Rarely, neonates with significant airway distress from unilat- eral paralysis may need a tracheotomy. If the infant or child is experiencing significant aspiration or dysphonia, surgical intervention may be recom- mended. Most commonly, the vocal fold is medialized by the injection of Teflon, gelfoam, or collagen under endoscopy or by external medialization via thyroplasty. Case numbers are small and studies are limited. Teflon has been reported to have an association with granuloma formulation and is not used as frequently (Parikh, 2004).
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Complications
For surgical interventions, a variety of complications can occur, including granuloma formulation, scar formation, ongoing voice or swallowing problems, and pneumonia.
VCD
VCD occurs when there is an abnormal movement of the vocal folds in the absence of other diseases. Another term used to describe this is paradoxic vocal fold motion (PVFM).
Epidemiology
PVFM may occur at any age in children; however, the median reported age of presentation is 14. There is a female preponderance in all age groups (Hicks, Brugman, & Katial, 2008). The true incidence may be higher;
however, among healthy, physically active adolescents and young adults, there are reports of incidence that range from 8 to 27% (Morris et al., 1999;
Abu-Hasan, Tannous, & Weinberger, 2005; Seear, Wensley, & West, 2005).
Pathophysiology
During a symptomatic period, there is paradoxical symmetrical adduction of the vocal folds toward the midline on inspiration. This causes obstruc- tion at the glottic level. There can also be expiratory obstruction with VCD.
At asymptomatic times, the vocal fold motion is normal (Christopher &
Morris, 2010).
Precipitating factors have been studied to determine etiologic factors in VCD. Upper airway hyperresponsiveness to a variety of triggers has been considered. While there is no absolute certainty in the triggers of the disease, those with VCD have reported such factors as acid reflux, upper airway infections, allergies, sinusitis, and irritants inhaled from accidental or occupational exposure (Hicks et al., 2008). Exercise may be a trigger and has been reported as a precipitating factor in 18% of people with VCD (Morris, Perkins, & Allan, 2006). Another factor thought to be implicated in VCD is significant psychological stress. Those with VCD may have higher levels of anxiety and more anxiety-related diagnoses (Gavin et al., 1998). The stress of competition for athletes may be noted more frequently as a trigger in exercise-induced VCD (McFadden & Zawadski, 1996).
Psychiatric disease has been reported as a factor as well. The most common disorder identified was conversion disorder, followed by depression, Munchausen’s syndrome, obsessive–compulsive disorder, and adjustment disorder (Lacy & McManis, 2004).
Signs and symptoms
There may be noisy breathing, stridor, wheezing, and/or difficulty breath- ing, which often occurs on inspiration but can occur on expiration. Cough,
146 Nursing Care in Pediatric Respiratory Disease
chest tightness, throat tightness, and changes in voice have been reported as well, though less commonly (Christopher & Morris, 2010). Symptoms may start and/or end abruptly. Children have presented with asthma-like symptoms and may be diagnosed with exercise-induced asthma. However, they report suboptimal response to bronchodilator therapy.
Diagnosis
Direct laryngoscopy performed at the time of symptoms is the gold stan- dard for the diagnosis of VCD (Morris et al., 2006). Spirometry can be helpful in the diagnosis of a symptomatic child but will not be helpful for children who are asymptomatic at the time of testing. If symptomatic, spirometry will typically reveal a flattened inspiratory loop.
Management
Once the diagnosis is certain, children should be supported and reassured that the condition is benign and self-limiting. Precipitating factors should be identified and avoided. The child may be referred for psychotherapy or psychological counseling and/or speech therapy. Psychotherapy may include biofeedback or hypnotherapy as part of the treatment plan. A speech language pathologist (SLP) can help in the evaluation and treat- ment of VCD. Therapy usually includes exercises to help abort acute attacks. The SLP can also teach therapeutic exercises to help prevent future episodes.
For exercise-induced VCD, anticholinergic inhalers may be helpful (Doshi & Weinberger, 2006). For acute episodes, there are reports of seda- tives and benzodiazepines being used successfully. Bronchodilators, ste- roids, and other asthma medications show minimal response, though heliox may afford a favorable response. In the event of a very acute onset of symptoms with the appearance of acute respiratory failure, children have been intubated. Often the symptoms quickly resolve and the child is extubated within 24 hours. There are reports of tracheotomy in the litera- ture as well (Christopher & Morris, 2010).
Complications
Complications are secondary to the acute or ongoing treatment of the child before diagnosis, including the overuse of asthma medications, such as corticosteroids. In extreme cases when intubation or tracheotomy is per- formed, there may be airway or surgical complications to the procedure.