TITLE: Paradoxical Vocal Fold Motion
SOURCE: Grand Rounds Presentation, UTMB, Dept. of Otolaryngology
DATE: August 25, 2009
RESIDENT PHYSICIAN: Ki-Hong Kevin Ho, MD
FACULTY PHYSICIAN: Michael Underbrink, MD, MBA
DISCUSSANT: Michael Underbrink, MD, MBA
SERIES EDITORS: Francis B. Quinn, Jr., MD, MS(ICS)
ARCHIVIST: Melinda Stoner Qui=
nn,
MS(ICS)
=
"This material was prepared by resident physicians in partial
fulfillment of educational requirements established for the Postgraduate
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gery
and was not intended for clinical use in its present form. It was prepared =
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y,
completeness, or timeliness. The material does not necessarily reflect the
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INTRODUCTION
Paradoxical vocal fold motion (PVFM) is an invol= untary functional disorder of the larynx characterized by intermittent adduction o= f more than 50% of the vocal folds during inspiration. It is often misdiagnosed as asthma and resulted in unnecessary drug use and hospitalization. This paper serves to highlight the characteristics of PVFM and describes its diagnosis= and management.
NOMENCLATURE
Since the description of PVFM as “hysteric croup” by Dunglison in 1842, there have been numerous terminologies u= sed to describe this condition, including episodic laryngeal dyskinesis, Munchausen’s stridor, pseudoasthma, functional upper airway obstructi= on, spasmodic croup, emotional laryngeal wheezing, irritable larynx syndrome, v= ocal cord dysfunction, etc. More recently, PVFM or paradoxical vocal cord moveme= nt has been used more frequently in the literature to give a more specific description of this condition.
EPIDEMIOLOGY
Various studies report the incidence of PVFM ran= ges from 3-10 %. It affects mainly children and young adults with average age at diagnosis of 14.5 years in children and 33 years in adults. There is a repo= rted 2:1 female predominance, with about 70-98% patients being female Caucasian. O’Connell et al reported that 20% of 164 female patients who underwent laryngoscopy for any reason were found to have PVFM.
PATHOPHYSIOLOGY
The exact etiology of PVFM remains unclear. Masc= hka et al proposed that PVFM might represent a spectrum of underlying diseases that manifest as a single clinical entity. In his classification system, Maschka divided the etiologies into organic and non-organic causes. Organic etiolog= ies included neurologic diseases and GERD. Nonorganic causes were classified as either conversion disorders or malingering and were believed to represent t= he vast majority of cases.
Ayers and Gabbott suggested that PVFM may be caused by laryngeal hyper-responsiveness initiated by an initial inflammatory insult that resulted in altered autonomic balance. Sub= sequent stimuli from irritants and psychogenic factors induce local presynaptic reflexes leading to vocal fold adduction and glottic closure.
ASSOCIATED CONDITIONS
Several conditions have been closely linked to P= VFM. The role of gastroesophageal reflux disease (GERD) has been elucidated in m= any studies. Powell et al found evidence of arytenoid edema or pachydermia on laryngoscopy in 21 of 22 pediatric PVFM patients Loughlin et al reported abnormal 24-hour pH probe study in 10 of 12 PVFM adult patients. In a recent study by Cukier-Blaj et al, about 70 % of PVFM patients were found to have = both abnormal reflux symptom index and laryngopharyngeal sensitivity scores cons= istent with laryngopharyngeal reflux disease.
Initially considered separate and distinct disor= ders, chronic cough and PVFM exhibit overlap in symptomatology, such as cough and dysphon= ia, and overlap in disease associations, namely asthma, GERD, and rhinosinusiti= s. Ryan and Gibson found evidence of P= VFM in approximately 56% of individuals with chronic cough using hypertonic saline challenge and fiberoptic laryngoscopy.
Psychogenic factors have been considered to play= a major role in PVFM since the original description of “hysteric croup”. Newman et al reported a previous psychiatric diagnosis in 73%= of patient with PVCM. Powell et = al noted that 55% of 20 adolescent females with PVCM had severe social stresses such as competitive sports. Prior history of sexual abuse has also been rep= orted to play a part in the development of PVCM.
PVFM is often misdiagnosed as asthma although th= ere might be close associations between the two conditions. Newman et al found = that 56% of the 95 PVFM patients had coexistent asthma. A study by the National Jewish center in 1994 showed that 30% of patients diagnosed with refractory asthma had co-existing PVFM.
DIAGNOSIS
History and clinical features:
Patients with PVFM often present with chronic refractory cough and frequent episodic dyspnea attacks. Cough is commonly exacerbated by irritants such as perfume, smoke, and strong odor. These patients may show signs of asthma but are not responsive to the regimen of bronchodilators and steroids. They may also present with hoarseness, dyspha= gia, and previous diagnosis of GERD.
Physical examination:
Physical examination may be normal when patients= are not experiencing an acute attack. Wheezing or stridor may be heard loudest = over the larynx. Direct visualization of vocal cords by laryngoscopy is the gold standard for diagnosis of PVFM. Classic finding on laryngoscopy is glottic closure of anterior vocal folds during inspiration with a small posterior chinking. If the patient is asymptomatic at the time of laryngoscopic examination, having the patient pant, breathe deeply and phonate may someti= mes elicit symptoms. Laryngoscopy also helps identify other laryngeal pathologi= es that may co-exist with PVFM, including unilateral vocal cord paralysis, subglottic stenosis, nodules, laryngomalacia, and sulcus vocalis as describ= ed in Patel’s study.
Pulmona= ry function test (PFT):
PFT with flow volume loops are often used as an adjunct to support the diagnosis of PVFM. In symptomatic patients, flow vol= ume loops may show a flattening of the inspiratory limb secondary to decreased inspiratory flow rate. However, 70-80% of PVFM patients were found to have normal PFT when asymptomatic.
Methac= holine challenge:
Methacholine is a cholinergic agent that can ind= uce bronchoconstriction. It is often used after PFT as a diagnostic test in ast= hma patients. Although it has been shown to induce acute attacks in PVFM patien= ts, its sensitivity is low. Perkins et al showed that only 2 of 8 PVFM patients previously diagnosed by laryngoscopy developed PVFM on methacholine challenge.
MANAGEMENT
Acute Management
The cause of the PVFM must first be elicited.
Heliox therapy may be used for immediate relief = of respiratory distress in PVFM. Heliox is a gaseous mixture of oxygen and hel= ium often found in ratios of 20/80 and 30/70 respectively. Because this mixture is less dense= than air, inhalation reduces turbulence in the airway and eliminates respiratory noise. It provides short-term relief of dyspnea in patients with both PVFM and other forms of upper airway obstructive disease.
Other acute measures include IPPV (intermittent positive pressure ventilation) and CPAP (continuous positive airway pressur= e) which widen the rima glottidis and also reduce turbulence. Panting brings a= bout acute relief by physiologically increasing the glottic aperture. Benzodiazepines and reassurance both reduce anxiety and therefore have been shown effective in terminating acute symptoms of PVFM.
Long-term Management
This requires a multidisciplinary approach invol= ving speech therapy, psychiatric support, and physician education regarding the syndrome. Speech therapy is regarded as the cornerstone of treatment for PVFM. The primary role of spee= ch therapy is to teach patients with PVFM how to control the laryngeal area an= d maintain an adequately open airway during respiration. Therapy with early recognitio= n of symptoms allows relaxation of neck, shoulder and chest muscles and promotes normal laryngeal breathing. Breathing exercise with regular steady rhythm c= an help patients learn to avoid inspiratory bursts that may trigger PVFM.
Psychotherapy should be initiated in patients if= there has been insufficient improvement with speech therapy alone or if significa= nt psychological components are present in history. Psychotherapy allows the pati= ent to explore for potential causes of the disorder and trains the patient with relaxation techniques. Educat= ing the patient about the condition is another method useful for reducing stress. Biofeedback may be us= ed in conjunction with psychotherapy for treating patients with PVFM.
Inspiratory muscle weakness has been linked with rapid, shallow breathing during heavy exercise and exercise-induced PVFM. I= nspiratory muscle training aims at increasing strength and decreasing respiratory effo= rt that may lead to a decreased sense of panic and struggle. The increased mus= cle strength may also enable patients to generate greater pressure differential= s to overcome laryngeal obstruction.
The long-term outcome of patients with PVCM is u= nknown as most of the literature consists of case reports and retrospective studie= s. Short-term response to speech therapy and psychotherapy showed good response with impr= oved functioning and fewer symptoms after intervention.
CONCLUSIONS
Symptoms of PVFM are non-specific and often misdiagnosed as asthma. PVFM is closely related to GERD, asthma, chronic co= ugh, and psychiatric disorders. A detailed history and laryngoscopic examination= are paramount in establishing the diagnosis of PVFM during symptomatic attacks. Management of PVFM is primarily medical with speech therapy and psychiatric evaluation as indicated. A prospective study is needed to evaluate the long-term outcomes of PVFM.
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DISCUSSANT: Michael Underbrink, MD, MBA
Basically it’s an unfortunate disease with= an unclear etiology.
It’s difficult to diagnose and typically w= e see this in the young adult and pediatric patients while they’re experien= cing some degree of a new stressor. It’s typically exercise induced in teenagers, and in older adu= lts it may be irritant induced. W= e try to get them to reproduce symptoms with that trigger, and in about one third= of them it’s nice when we can confirm those symptoms and signs with laryngoscopy.
I think it’s worthwhile to examine these patients together with the speech pathologist. We teach relaxation breathing tech= niques and have the patient focus on expiratory breathing. If you have him inhale throu= gh the nose and exhale through the mouth you can break a laryngospasm very easily = by remaining calm as you talk them through this.
I haven’t had a case of this in which I ha= d to use heliox therapy and I hope I never do.&= nbsp; Medical treatment and followup is the cornerstone or treatment.
Pulmonologists are quite aware of this problem a= nd they are pretty quick to send a consult your way if it is severe and the patients are non-responsive to treatment for asthma. Use of sedatives or muscle relaxan= ts is not advisable because of their possible respiratory suppressive effect. A trial of heliox therapy should p= recede intubation if available.
Some people uniformly treat these patients with anti-reflux medications but I don’t consider it necessary unless they have signs and symptoms of Laryngopharyngeal Reflux Disease (LPRD).
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REFERENCES
Powell DM, Karanfilov BI, Beechler KB, et al. Paradoxical vocal cord dysfunction in juveniles. Arch Otolayngol Head Neck Surg 2000;126:29–= 34.
Morris MJ, Allan PF, Perkins PJ. Vocal cord dysfunction, aetiologies and treatment. Clin Pulm Med 2006;13:73–86.<= /p>
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Maschka DA, Bauman NM, McCray PB, Hoffman HT, Karnell MP, Smith RJ. A classification scheme for paradoxical vocal cord motion. Laryngoscope 1997;107:1429–1435
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Powell DM, Karanfilov BI, Beechler KB, et al. Paradoxical vocal cord dysfunction in juveniles. Arch Otolayngol Head Neck = Surg 2000;126:29–34.
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Newman KB, Dubester SN. Vocal cord dysfuncti= on. Masquerader of asthma. Sem Resp Crit Care Med 1994;15:161–7.
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