The importance of recognizing paradoxical vocal fold dysfunction: A case report of a 13-year-old girl presenting with stridor

Abstract

The present report details the case of a 13-year-old girl who presented to the emergency department with stridor. Treatment for presumed reactive airway disease was attempted with antibiotics, nebulized adrenaline masks and high-dose corticosteroids. Over the next month, she presented repeatedly in a similar fashion and was admitted to hospital on three separate occasions. Ultimately, she was referred to the Centre for Paediatric Voice and Laryngeal Function at The Hospital for Sick Children (Toronto, Ontario) for a speech-language pathology evaluation and direct laryngoscopy. The patient was diagnosed with paradoxical vocal fold dysfunction. After a brief treatment session with a speech-language pathologist, her stridor completely resolved and paradoxical inspiratory vocal fold adduction was no longer visualized on direct laryngoscopy. The present case highlights the fact that paradoxical vocal fold dysfunction can mimic other entities that present with stridor, and misdiagnosis can result in significant morbidity. Investigation into a patient’s social history and stressors can facilitate the diagnosis, and can avoid unnecessary and potentially harmful medical and surgical interventions.

Paradoxical vocal fold dysfunction (PVFD) is characterized by inappropriate adduction of the vocal folds during inspiration. Clinically, this phenomenon may present dramatically as dyspnea, chest tightness, coughing, wheezing or stridor. Associated voice symptoms can range from complete aphonia to mild hoarseness (1). This clinical presentation can lead to a misdiagnosis of reactive airway disease or asthma, or upper airway obstruction. The ‘typical’ patient with PVFD has been described as a single woman between 20 and 40 years of age, who may exhibit anxiety, depression or perfectionism (2). Often, these patients have at least 12 years of formal education and some connection to working in health care (3). Many patients have a history of childhood asthma and/or gastroesophageal reflux disease (GERD)-induced ‘croup’ (4). However, PVFD has also been described in adolescents (5). PVFD is an important condition for general paediatricians to be familiar with; they should be able to distinguish it from reactive airway disease based on clues from medical history, physical examination and investigations.

CASE PRESENTATION

A 13-year-old girl presented to the emergency department (ED) complaining of upper chest and throat ‘tightness’ of a 12 h duration. In the preceding week, she had been experiencing laryngitis consisting of a sore throat and a hoarse voice, and had been in contact with several children with upper respiratory tract infections. Her medical history was unremarkable other than experiencing some mild wheezing and respiratory symptoms each spring in relation to environmental allergies.

The ED physician noted that the patient was anxious and presented with clinical signs of hoarseness, inspiratory stridor, wheezing and tracheal tugging. She was afebrile, her respiratory rate was 20 breaths/min and her oxygen saturation was 100% in room air. The remainder of her examination was normal. Her chest x-ray and lateral soft tissue x-rays of the neck were also normal. Routine bloodwork revealed a normal white blood cell count of 7.4×10⁹/L (normal range 4×10⁹/L to 10×10⁹/L).

She was treated in the ED with nebulized adrenaline and salbutamol masks, and the otolaryngology service was consulted. A limited (by patient tolerance) fibre optic nasolaryngoscopic examination revealed mild edema of the supraglottic structures. She was admitted to hospital with a diagnosis of supraglottitis, and treatment with intravenous dexamethasone and clindamycin was initiated. Her condition improved, and after four days, she was discharged from hospital on a tapering dose of oral dexamethasone, oral clarithromycin and inhaled salbutamol as required.

She was admitted to hospital twice for the management of nonspecific respiratory symptoms requiring a total of 14 days in hospital. In addition, she was prescribed omeprazole and dimenhydrinate for associated gastrointestinal symptoms. Further investigations included repeat chest x-rays and lateral soft-tissue x-rays of the neck, as well as computed tomography scans of the neck and chest, all of which were normal.

Three weeks after her initial presentation to the ED, and while an inpatient, she was referred to the voice clinic for a repeat laryngoscopy. At the time of the referral, she had developed a severe steroid-induced rash on her face, chest and back. She was suffering from abdominal discomfort and lack of appetite, which led to a 4.5 kg weight loss. She was lightheaded and significantly fatigued.

Rigid laryngoscopy demonstrated normal anatomical structure of the vocal folds and supraglottic structures. During inspiration, paradoxical adduction of the vocal folds was repeatedly noted (Figure 1A). The vocal folds, however, would abduct appropriately when she needed to catch her breath and when she was asked to sniff air through her nostrils. Her ability to abduct the vocal folds eliminated a diagnosis of vocal fold paralysis. On phonation, severe supraglottic compression was observed (Figure 1B) resulting in a strained and hoarse voice. These findings were consistent with a diagnosis of PVFD.

Figure 1).

Still images obtained during rigid laryngoscopic examination of a 13-year-old girl with paradoxical vocal fold dysfunction before (A and B) and after (C and D) therapy. During the inspiratory phase of the respiratory cycle, adduction of the vocal folds was observed (A), resulting in an audible stridor. Note the classic finding of anterior vocal fold closure with ‘posterior chinking’, the diamond-shaped margination between the posterior vocal folds and the corniculate tubercles. On phonation, supraglottic compression was noted (B), particularly on the patient’s right side. Post-therapy, the patient’s stridor resolved and normal vocal fold function was noted during inspiration (C) and phonation (D)

The presumed diagnosis of PVFD was confirmed with the use of therapeutic techniques designed to counteract the paradoxical movement of the vocal folds. A variety of exercises were introduced to the patient, including inhaling through the nose with the lips closed, prolonged audible exhalation through pursed lips (lip trills) and prolonged audible exhalation while producing a ‘s’ sound. Pictorial diagrams and video laryngoscopy images were used to explain the rationale behind these exercises. The patient was counselled to practice the exercises daily and at the earliest sign of onset of symptoms. Repeat laryngoscopy following the first treatment session revealed normal vocal fold function during abduction and adduction (Figures 1C,D).

Interestingly, further inquiry into the patient’s social history revealed that she was experiencing a significant level of stress related to her academic and extracurricular activities. She was involved in singing lessons and performances, piano lessons and her school’s swimming team. The parents were not aware of the patient’s degree of stress. A recommendation for supportive and psychological counselling was suggested to the family.

DISCUSSION

The prevalence of PVFD is not known. It occurs at all ages, with the highest rate in the paediatric population among adolescent girls (4). PVFD has been described in paediatric populations with asthma, as well as in children without coexisting respiratory disease (5). In adult populations with asthma, PVFD coexists in 10% to 40% of patients (6, 7), and may contribute to the apparently refractory nature of the asthma. It is not uncommon for PVFD to be misdiagnosed as asthma or upper airway obstruction. Unfortunately, misdiagnosis can lead to potentially harmful medical and surgical interventions including high-dose, long-term bronchodilator and corticosteroid treatment (7, 8), intubation (7) and tracheotomy (9, 10).

The ability to distinguish asthma from PVFD is an important skill for primary care physicians working with paediatric populations. Clinical features that should raise the suspicion of PVFD include dyspnea out of proportion to the clinical signs; asthma-like symptoms that do not respond as expected to bronchodilators or corticosteroids, or are precipitated by stress; and athletes who experience a choking sensation during exercise (Table 1). In the present case, clues to the diagnosis of PVFD included inspiratory stridor, the lack of hypoxemia, essentially normal physical examination, bloodwork and imaging, and the lack of a consistent response to bronchodilators and corticosteroids. Moreover, the patient’s age (13 years) is very atypical for a first presentation of croup, supraglottitis or reactive airway disease. Most important, there was a clear association between the patient’s level of stress (high expectations for achievement in academic and extracurricular activities) and her respiratory symptoms.

TABLE 1.

Features distinguishing paradoxical vocal fold dysfunction from asthma

Feature	Paradoxical vocal fold dysfunction	Asthma
History
Incidence	Less common	More common
Age	Adolescent predominance	Any age
Sex	Female predominance	Male predominance in childhood; 1:1 at puberty
Triggers	Exercise, emotional stress	Many
History of allergy	Usually absent	May be present
Family history	Usually absent	May be present
Sensation of tightness	Throat	Chest
Dyspnea	Yes	Yes
Nocturnal symptomatic wakening	Rare	Common
Psychological factors	Important role in some cases	Less important role
Anxiety attacks, if present	Usually precede respiratory symptoms	Usually follow respiratory symptoms
Physical examination
Expiratory wheeze	Greatest over larynx	Greatest over lung fields
Cough	Yes	Yes
Inspiratory stridor	Common, especially over larynx	Rare
Sputum production	Rare	Common
Investigations
Response to medication (eg, bronchodilators)	No response/’refractory’	Good response
Eosinophilia	Rare	Common in allergic asthma
Hypoxemia	Rare	Common
Hypercapnia	Rare	More common
Chest x-ray	Usually normal	May show hyperinflation, peribronchial thickening
Residual volume, total lung capacity	Normal	May be increased
Flow volume loop	Flattened inspiratory loop	Obstructive pattern
Bronchial provocation testing	May be positive	Usually positive
Laryngoscopy	Adduction on inspiration; posterior glottic closure	Usually normal; no posterior glottic closure

Adapted from Ibrahim et al (23)

It is known that episodic PVFD may manifest in association with psychosocial stressors (5) and during heightened physical activity (3, 11). These patients frequently demonstrate characteristic personality traits such as little tolerance for failure and high academic and performance standards; they may be under parental pressure to succeed (3, 12, 13). Children and adolescents with PVFD tend to be high achievers and participate in competitive sports (3). In a recent retrospective study (4), 55% of paediatric patients had social stresses including involvement in extracurricular activities and competitive sports. Other studies have proposed a link between psychological stressors or illness and PVFD, and some have further suggested that these patients may be divided into two groups – a group of malingering patients motivated by secondary gain, and a second group with conversion disorders who are overwhelmed by psychological stresses (14). If not fully addressed, these psychological stressors could manifest as other conversion disorders. Although psychopathology is not a typical feature of PVFD in paediatric patients, there are case studies (15) of PVFD in patients with post-traumatic stress disorder secondary to sexual abuse.

A wide variety of possible triggers for PVFD have been reported in addition to psychosocial stressors. Powell et al (4) reported a high prevalence (95%) of posterior glottic changes typically associated with GERD on laryngoscopic examination. However, there is controversy surrounding the validity of using laryngeal findings to diagnose GERD (16). Postnasal drip from sinusitis, respiratory tract infections, and irritants such as smoke, gases, dust, airborne pollutants and odours have also been linked to PVFD (17).

Physical examination of a patient with PVFD is usually normal between episodes. During symptoms, the physical examination reveals inspiratory or expiratory stridor or wheezing that may be transmitted throughout the chest, but is loudest over the larynx, trachea and larger airways. The degree of respiratory distress is variable. If the patient does not present with symptoms at the time of the evaluation, an episode may be triggered through exercise (climbing stairs or walking on a treadmill) (1).

In terms of adjuvant tests, patients typically have normal pulse oximetry, arterial blood gases and imaging; they do not respond to histamine or methacholine challenges. In terms of pulmonary function testing, flow volume loops obtained during attacks typically show a flattened inspiratory component (18). Laryngoscopy (without sedation) is considered the diagnostic standard. On examination, vocal fold adduction during inspiration is observed. To rule out bilateral vocal fold paralysis, normal vocal fold abduction must also be observed or elicited. Abduction can be elicited by having the patient repeatedly sniff nasally.

The mainstays of therapy for PVFD include laryngeal control therapy using speech and breathing techniques, and psychological counselling (4). Speech therapy helps resolve symptoms once they occur. Therapy techniques involve breathing and vocalization exercises to indirectly relax the laryngeal and oropharyngeal musculature, and to promote an open airway during breathing (1, 19–21). Laryngeal relaxation is established by maintaining continuous airflow through the glottis. However, psychological counselling is critical to ultimately treat and prevent future episodes of PVFD. Thus, once the diagnosis of PVFD is made, appropriate psychological evaluation should be obtained. Psychotherapy allows the patient to explore and alleviate the potential causes for the disorder, and trains the patient with relaxation techniques and the development of new coping strategies for stress-related triggers. Family therapy and hypnosis have also been used as treatment for patients with PVFD (22). Other important aspects of treatment include patient education and cessation of unnecessary medication. If associated with conditions such as GERD, lifestyle modifications or additional medications may be helpful. Prognosis is excellent once the patient and family understand the diagnosis and undertake speech-language pathology treatment and psychotherapy.

CONCLUSIONS

PVFD should be considered in the differential diagnosis of paediatric patients with presumed refractory reactive airway disease. The workup of these patients to facilitate accurate and timely diagnosis includes a careful clinical history focusing on symptoms, triggers and psychosocial stressors; physical examination; and adjuvant investigations including pulmonary function tests, laryngoscopic evaluation, speech-language pathology evaluation and psychological evaluation. A team approach including expert clinicians from the departments of paediatrics, otolaryngology, speech-language pathology, psychology and psychiatry is recommended.

The diagnosis of PVFD requires a high degree of suspicion, and should be considered particularly when the degree of dyspnea is out of proportion to clinical signs or when there is little response to standard treatment. Early diagnosis can avoid repeated ED visits and hospitalizations, as well as potentially harmful medical and surgical treatments.