Pediatric Paradoxical Vocal-Fold Motion: Presentation and Natural History

DISCUSSION

Our demographic data are consistent with those in previous reports showing that PVFM predominantly affects adolescent girls.^1,4,17 Many of our patients carried a diagnosis of asthma, yet only 2 had a PFT result consistent with asthma. Asthma and PVFM can occur simultaneously, but the lack of response to asthma medications, a change in a child's typical asthma pattern, or absence of expiratory obstruction on spirometry testing should point to PVFM.^11,17 PVFM symptoms predominate with exercise; <15% of our patients had symptoms at rest only. Our symptom data are also in agreement with those of previous research in which the most common complaints were dyspnea, throat tightness, and stridor with a predominant inspiratory component.^6,8 It should be noted, however, that inspiratory stridor is not a requirement for the diagnosis, because expiratory and biphasic stridor have been reported in patients with PVFM.⁵

The majority of our patients were not found to have vocal-fold adduction on inspiration during examination. It is difficult to elicit findings in many children with PVFM, because it is often impossible to replicate the specific exercise conditions under which their symptoms begin. Previous series have shown the ability to elicit physical examination findings in <50% of patients.^18,19 However, it is interesting that we were able to visualize inappropriate vocal-fold adduction in the majority of children who complained of symptoms at rest. Similar to other clinicians and researchers, it has been our approach to not regard FOE as the gold standard for diagnosing PVFM. Although we do evaluate all of our patients with FOE, our experience has indicated that clinical history, symptoms, and thorough evaluation and exclusion of primary pulmonary, neurologic, and cardiac entities are sufficient to make a diagnosis of PVFM.

Our overall treatment-success rate was 76%. Speech therapy had a high success rate in patients who presented with symptoms only during exercise. Speech therapy was not as successful for patients who presented with symptoms at rest only. No child improved when placed on PPI therapy alone. Even in 3 children for whom a pH-probe study confirmed GERD, there was no improvement with PPI therapy alone. There was no significant difference in success rates between speech therapy alone and speech therapy with a PPI, which is most likely because of the small sample size; a much larger, prospective efficacy study would need to be conducted to determine if PPIs have a synergistic effect with speech therapy or if PPI therapy is necessary at all. Although GERD is often cited as a common cause of PVFM in adults, the literature does not support a strong association. Arytenoid edema, interarytenoid edema, and pachydermia have been suggested as physical examination signs of GERD and associated with PVFM, but these physical examination findings have not been correlated with results of pH-probe studies or impedance testing in children.^5,8 Given our findings, we would not advocate a PPI as a sole treatment for PVFM. We do not start all of our patients with PVFM on empiric PPI therapy, and we recommend only giving it to children with overt GERD symptoms. Furthermore, the children who are put on PPI therapy are also sent to speech therapy as the primary treatment modality.

Our treatment failures deserve special comment. Three children's cases did not meet our definition of successful treatment. Interviews with these children and their families revealed that although they had occasional symptoms, their overall status improved significantly with speech therapy, enough so that they felt that they did not need further treatment. The symptoms of an additional 3 patients did not respond to initial speech therapy, and they did not seek additional treatment. These children had symptoms that resolved spontaneously, on average, 2 years after being initially seen. The remaining 8 patients continued to have symptoms at their last follow-up visit or phone call, and they did not plan on seeking further treatment. There were 2 common reasons why the patients for whom treatment failed discontinued treatment. One explanation was the lack of available local speech therapy or psychiatric resources and the inability to commit significant travel time to attend specialized therapy. A second explanation was that many children simply stopped playing the sport that caused the symptoms. From these data it is difficult to comment on the natural history of PVFM, because initial treatment strategies have a fairly high success rate.¹⁹ Only prospective studies will provide insight into whether children simply outgrow their symptoms or continue to be at risk through their adult life.

Many case reports have associated PVFM as a laryngeal manifestation of stress or other psychiatric disorder.^12,13,20 Approximately 10% of the patients in our cohort presented with a known diagnosis of anxiety or depression. An additional 12 children were found to have an underlying psychiatric diagnosis once PVFM treatment began; thus, 30.5% of our patients had an underlying psychiatric condition. Anxiety was particularly prominent, which suggests that there is a significant association between PVFM and anxiety. These children's PVFM symptoms responded well to psychiatric treatment: resolution occurred in <3 months for most patients. Overall, psychiatric treatment was successful both for those patients who had symptoms at rest and those whose symptoms did not improve with speech therapy. Patients referred to psychiatric care were more likely to have symptoms at rest and to have inappropriate vocal-fold adduction at rest. Although the numbers are small, our data would suggest that children with PVFM symptoms at rest are better treated with psychiatric treatments initially. PVFM symptoms at rest may also be a harbinger of psychiatric disease that requires additional treatment, because half of the children in our study who had symptoms at rest and received psychiatric care required prolonged psychiatric care after their PVFM symptoms resolved.

From symptom presentation and outcome data, we formulated a treatment algorithm that may aid those who see children with PVFM (Fig 2). The goal of this algorithm is to help reduce treatment inefficiencies; studies have found that patients with undiagnosed PVFM use health care resources at a higher rate than age-matched controls with moderate-persistent asthma.²¹ One portion of this algorithm that should be stressed is the need to rule out cardiac and neurologic disease. Finally, as we alluded to in “Results,” there is a very small number of children whose symptoms are so debilitating that surgical intervention may be required as a temporizing measure to alleviate significant symptoms that prevent normal activities of daily life. Botulinum toxin may provide temporary relief so that a patient can participate in speech or psychiatric treatment. Botulinum toxin injection is not a long-term cure and should only be used when traditional therapies have failed.

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FIGURE 2

Proposed algorithm for children with suspected PVFM. ^a Children with GERD symptoms will most likely need a trial of speech therapy or biofeedback for long-term successful treatment. EKG indicates electrocardiogram.

Limitations of our data include their retrospective nature and the fact that all patients were evaluated in a multidisciplinary airway clinic with relatively easy initial access to specialized speech therapists and child psychiatrists. Our outcome data are limited by the subjective nature of reporting, because there is no objective test to determine the resolution of airway symptoms. We are unable to determine long-term results, because the children were followed until their last documented clinic visit. In most instances, this last visit was marked by successful speech or psychiatric therapy and the provider felt that no further treatment was necessary. This prevents us from commenting on recurrence rates, but our general clinical experience is that once the children learn adequate breathing control, they can successfully use these techniques during symptom recurrence. From our originally identified 68 patients, 9 were lost to follow-up, which left us with a cohort of 59 patients. Six of the patients for whom we considered treatment to have failed had partial or complete resolution of their symptoms; thus, our symptom-resolution rate is likely higher than our treatment-success rate. Furthermore, although our reported population was robust, the populations of certain treatment groups such as those children who received PPI therapy and those who received psychiatric care were relatively small. To carry out a treatment-efficacy study of speech therapy, speech therapy with concurrent PPI therapy, and PPI therapy alone, 103 subjects per group would be needed to obtain at least 80% power.

PVFM can be a frustrating entity for both patient and physician. Patients are usually frustrated because they can go for a significant time without an accurate diagnosis and appropriate treatment. Providers can be frustrated with the various terminology used to describe this disorder, the fact that the symptoms overlap with asthma, and the lack of clear treatment algorithms.⁹ Because of the relative infrequency of this diagnosis, future insights into evaluation and treatment will only come from collaborative studies at multidisciplinary centers. We hope that our proposed algorithm will be a starting point for more efficient evaluation, treatment, and research of these patients.