|Home | About | Journals | Submit | Contact Us | Français|
Objective: To present for discussion a case of paradoxical vocal-cord dysfunction (PVCD), an uncommon disorder that may be misdiagnosed as, or coexist with, exercise-induced asthma (EIA).
Background: Vocal-cord dysfunction results from paradoxical closure of the vocal cords during the inspiratory phase of respiration and may be mistaken for EIA, resulting in unnecessary medical treatment and a delay in diagnosis. Although PVCD is uncommon, athletic trainers should be aware of the disorder, as they may play an important role in its diagnosis and treatment.
Differential Diagnosis: Exercise-induced asthma, foreign body aspiration, anaphylactic laryngeal edema, bilateral vocal cord paralysis, extrinsic airway compression, laryngomalacia, subglottic stenosis, traumatic edema, or hemorrhage.
Uniqueness: This case report describes a common presentation of an unusual disorder. By obtaining a detailed history from the athlete and having a high index of suspicion for the disease, we were able to diagnose PVCD, discontinue all EIA medications, and begin treatment.
Conclusions: The athletic trainer can play a valuable role in the diagnosis of PVCD, which must be considered in the differential diagnosis for any athlete who is compliant with the medications prescribed for the treatment of EIA yet shows little or no improvement in symptoms. A high index of suspicion for PVCD will greatly aid health care professionals assessing the athlete.
Paradoxical vocal-cord dysfunction (PVCD) is defined as a paradoxical closure of the vocal cords during the inspiratory phase of respiration.1 Such closure results in partial, sometimes severe, obstruction of airflow. An entity with symptoms similar to PVCD was first described in 1842.2 The past few decades have seen an increasing number of reports of PVCD in the literature. A few of these reports have described PVCD presenting similarly to exercise-induced asthma (EIA) in athletes,1–6 while others have discussed patients with severe, intractable asthma.7,8 Vocal-cord dysfunction is a relatively rare disorder, although Rice et al9 speculated that the prevalence may be as high as 3% among intercollegiate athletes. Patients with PVCD are typically young women; however, young men constitute about one third of the adolescent cases reported.1
In the following case report, we present a high school athlete with the presumptive diagnosis of EIA who remained symptomatic despite multiple medication trials over the preceding year. After consultation with the team physician (M.C.K.), the athlete underwent further diagnostic testing, which confirmed the suspected diagnosis of PVCD.
A 17-year-old female high school athlete presented to the team physician for further evaluation of EIA, which had been diagnosed by her family physician the previous year. Her symptoms began during basketball season of her freshman year of high school. She complained of dyspnea during and immediately after activity. She occasionally had a persistent cough lasting several hours after exertion and complained of excessive postexertional fatigue. Her symptoms were much more prominent while playing basketball (both regular season and summer league) than during participation in soccer or other athletic activities. Symptoms were also more pronounced during games. Upper respiratory infections occasionally triggered mild coughing. She had no past history of asthma, nocturnal cough, allergic rhinitis, wheezing with upper respiratory infections, reactive airways disease, or environmental allergies. She occasionally had mild dyspepsia after meals. There was no family history of asthma.
She had previously been treated with multiple medications (exact dosages unknown), including the use of an albuterol metered-dose inhaler (MDI) before exercise and prophylactic regimens of montelukast sodium (Singulair, Merck & Co Inc, West Point, PA), zafirlukast (Accolate, Zeneca Pharmaceuticals, Wilmington, DE), triamcinolone (Azmacort, Rhône-Poulenc Rorer, Collegeville, PA), and salmeterol (Serevent, Glaxo Wellcome Inc, Research Triangle Park, NC). Each medication had been tried for only short periods of time, generally no more than 3 to 4 weeks, and was discontinued either at the direction of her physician due to ineffectiveness or by the athlete out of frustration that it was not helping.
Physical examination revealed a healthy-appearing adolescent girl (height = 169 cm, weight = 61 kg) in no acute distress. Her nares were clear with no discharge or irritation of the mucosa. Lungs were clear to auscultation bilaterally with a normal inspiratory-to-expiratory ratio. Her chest had a normal anterior-posterior diameter with no bowing of the sternum. Her heart had a regular rate and rhythm and normal S1 and S2 heart sounds with no murmurs, rubs, or gallops. Her extremities showed no clubbing of the fingernails or cyanosis.
After the initial evaluation, she was given a 4-week trial of fluticasone (Flovent, Glaxo) 44 μg by MDI, and salmeterol 42 μg by MDI, each at a dose of 2 puffs twice per day, and cromolyn sodium 800 μg MDI, 4 puffs before exercise, while diagnostic testing was arranged. She reported no benefit from the new medications.
Pulmonary function testing (PFT) was performed before exercise, after 15 minutes of high-intensity aerobic activity (running), and after inhalation of albuterol. The PFT results (Table (Table1)1) were highly suggestive of PVCD as the cause of her symptoms. She was referred to an otolaryngologist for definitive diagnosis. Laryngoscopy was performed after provocation of her symptoms with exercise and revealed closure of her vocal cords during the inspiratory phase of respiration, thus confirming the diagnosis of PVCD.
After the diagnosis of PVCD was confirmed, the athlete underwent several sessions with a speech therapist to learn corrective breathing techniques. She was also assured that her PVCD was exacerbated by increased stress in certain situations and, with work, she would be able to overcome her symptoms. All EIA medications were discontinued, and she concentrated on the breathing techniques she had been taught.
At the time of manuscript preparation, she was 6 months postdiagnosis and had completed her soccer and basketball seasons (earning All-Conference honors in each sport) with minimal symptoms.
Exercise-induced asthma is common among active people, with an overall incidence of 12% to 15%,10 although the prevalence may be even higher among elite athletes.11 Exercise-induced asthma is defined as “reversible airway obstruction that occurs during or after exertion.”12 Specific symptoms include chest tightness, wheezing, coughing, and shortness of breath, which result from acute narrowing of the lung's small airways. The exact mechanism of the airway narrowing and obstruction is not known, but 2 current theories suggest increased minute ventilation, causing (1) water loss in the cells of the bronchial mucosa, and (2) cooling of the airways. Each may potentially lead to release of cell mediators and subsequent inflammation and asthma.13
The diagnosis of EIA may be suspected after taking a thorough history of exercise-related symptoms. The diagnosis is confirmed by PFTs performed before and after exercise provocation. A drop in maximum volume of expired air in one second (FEV1) of more than 15% is diagnostic of EIA.12 While a positive result is indicative of EIA, a negative test result does not rule out the disease. Therefore, if EIA is still suspected, other tests that provoke bronchoconstriction may be given, such as inhalation of methacholine, histamine, or cold air.13
Initial treatment typically involves prophylactic inhalation of a beta-agonist medication (usually albuterol) 15 to 20 minutes before exercise, although nonpharmacologic treatment is an option.14 Beta-agonist medications are 80% to 95% effective in alleviating the symptoms of EIA.15 If an athlete does not respond to initial treatment, a detailed history and physical examination must be repeated, and additional diagnostic testing may be pursued as other possible diagnoses are considered.
Vocal-cord dysfunction and EIA can present in strikingly similar manners and may even coexist. However, several historical clues aid health care professionals in developing a high index of suspicion for PVCD (Table (Table2).2). Exercise-induced asthma symptoms typically peak 5 to 10 minutes after exercise begins and often spontaneously resolve within 30 to 60 minutes with continuous exercise. Coughing may persist for several hours after the cessation of activity, and the symptoms are typically reproducible under similar conditions. Our patient showed inconsistency in symptoms, in that soccer did little to provoke her symptoms, whereas basketball caused her most serious exacerbations. An individual with EIA would be expected to have similar symptoms in each sport, as they are both considered highly “asthmagenic” secondary to the high minute ventilation required.12 Such inconsistency in symptoms could be secondary to allergen exposures (molds in a gymnasium, pollens outside), but she had no other allergic symptoms.
Symptoms in PVCD are often situation dependent and may begin and end abruptly. The afflicted individual may describe a sensation of throat tightness or choking. The inspiratory phase of respiration may be audible during an acute attack, and symptoms may be interrupted by distracting the athlete or instructing her to begin panting. Athletes with acute EIA exacerbations are unable to catch their breath and pant effectively. While these historical clues can be helpful, they may be absent or inconsistent in PVCD.
Auscultating the chest during an acute episode may also help to differentiate EIA from PVCD. Stethoscope examination of an athlete with onset of EIA symptoms should reveal wheezing, while an athlete with PVCD may have stridor. Wheezing is described as a “whistling, squeaking, or puffing sound” and “to breathe with difficulty and noisily.” Stridor is identified as “high-pitched, noisy respiration, like the blowing of wind” and may be heard without the aid of a stethoscope. While these lung sounds are certainly not mutually exclusive, they typically do not occur simultaneously. In general, stridor is associated with upper airway (trachea, larynx) diseases, such as croup and PVCD, and can occur during both inspiration and expiration. Wheezing is caused by the passage of high-velocity air through narrowed bronchi16; although it may be heard with both inspiration and expiration, it is most typically associated with expiration and is the most common physical examination finding in asthma.
Beta-agonist medications are considered so effective in EIA treatment that a poor or insufficient response should prompt a more thorough diagnostic evaluation.3 Preexercise and postexercise PFTs are indicated if they were not initially obtained. Proper use of the medication must be assessed by observing the athlete's use of the MDI. Correct timing (before exercise) and compliance with therapy must also be discussed, and the athlete should be observed for compliance with therapy by a coach or athletic trainer. Most individuals who are unresponsive to initial attempts at therapy will indeed be proven to have EIA; however, they require additional medical therapy to control their disease.
An in-depth discussion of pulmonary mechanics and PFTs is beyond the scope of our report, but an explanation of some important data will assist in understanding the findings (Table (Table3).3). A variety of unusual PFT results can help differentiate PVCD from EIA; however, these findings are quite variable in PVCD. Our patient provides an excellent example, as her PFTs showed all of the unusual features of PVCD. First, the inspiratory portion of her preexercise (baseline) flow curve is characteristic of upper airway obstruction (Figure (Figure1).1). Thus, she showed an abnormal curve while asymptomatic, a finding that occurs in almost one fourth of individuals with PVCD.2 A normal curve (Figure (Figure2)2) has an elliptic shape, while upper airway obstruction, such as that resulting from vocal-cord closure, results in flattening or truncation of the curve.
Her FEV1 showed a 19% decrease after exercise challenge, which meets the criteria for EIA. However, all available data must be reviewed before making a diagnosis. While PVCD and EIA may coexist, further analysis of the PFT data ruled out comorbid disease. She also had a decrease of 18% in her total expired lung volume (FVC); thus, the FEV1/FVC ratio was unchanged, a finding consistent with PVCD. Exercise-induced asthma may also cause a decrease of FVC, but the drop will not be in proportion to the FEV1 decrease.1 However, after treatment with a bronchodilator (albuterol), our patient's FEV1 improved 13% and her FVC increased 15%. Although this finding is difficult to explain, we postulate that it likely resulted more from relaxation in breathing technique after the treatment than from a pharmacologic effect of the medication.
The forced expiratory flow from 25% to 75% of vital capacity (FEF25%–75%) reflects airflow through the small airways of the lungs. The small airways are the most affected by any degree of asthma resulting from EIA. Therefore, an individual with EIA shows a large decrease in this value after an exercise challenge. Our patient's decrease of 6% is not considered significant. There was also minimal change after administration of the bronchodilator. Finally, the ratio of forced expiratory to inspiratory flow at 50% of vital capacity (FEF50%/FIF50%) is normally less than 1; however, with the inspiratory obstruction caused by the closure of the vocal cords, the ratio is typically greater than 1, as it was with our patient.1
Although the PFTs were highly suggestive of PVCD, the patient was referred to a pediatric otolaryngologist for definitive diagnosis. Vocal-cord dysfunction can only be confirmed by finding paradoxical closure of the vocal cords in a symptomatic patient upon inspiration during laryngoscopy. However, in patients in whom the history and PFTs are consistent with PVCD, some authorities recommend foregoing laryngoscopy, initiating speech therapy, and observing for resolution of symptoms (Steve Simons, unpublished data, 2001). If symptoms persist, diagnostic laryngoscopy is indicated. Of note, laryngoscopy may be normal in 50% of individuals with PVCD if symptoms cannot be elicited before the examination.2
The symptoms found in both PVCD and EIA may be secondary to other causes. The differential diagnosis is quite broad, as listed in Table Table4.4. Fortunately, the other disorders are quite rare and can typically be ruled out on the basis of history alone. Anaphylactic laryngeal edema may present acutely with stridor similar to that sometimes seen in PVCD; however, the athlete will have additional physical examination findings such as angioedema, flushing, pruritis, hypotension, and hives.17 If such findings are present on examination, the emergency medical services system should be activated while the athletic trainer provides initial first aid as needed. Acute trauma and inhaled foreign bodies (typically food or insects) may also result in acute stridor and dyspnea, but the history should be conclusive.
Anxiety and emotional stress may contribute to the symptoms experienced in PVCD; however, controversy exists regarding the role of these factors in the disorder. The implication of a psychological cause for PVCD may promote undue stress in an athlete or her family, so these factors must be discussed with care by the athletic trainer and team physician. In addition, a review of the medical literature by an athlete with PVCD may also raise similar issues. Many articles emphasize the psychiatric aspects of PVCD, and some early reports go as far as describing PVCD as a conversion disorder.2 One study in particular deserves mention. Freedman et al18 reported a 36% incidence of childhood sexual abuse among individuals with PVCD, but they did not study a control population. The incidence of sexual abuse in the general female population ranges from 6% to 62%19; thus, the study's findings are insignificant. The presumption of a psychogenic cause will likely alienate the athlete before the initiation of any treatment plan.1
The primary reason for much of the emphasis upon the psychological factors for PVCD in the literature lies in the early experience with the disorder in patients with intractable asthma. Only recently have investigators looked at PVCD alone in comparison with control groups. Gavin et al20 reported that patients with PVCD as their only diagnosis were not different from asthmatic controls on measures of family functioning, but they did experience higher levels of anxiety. However, the study population consisted of adolescents who sought treatment for severe asthma at a specialty center and were ultimately found to have PVCD rather than asthma. Applying the psychiatric findings of individuals with PVCD so severe that it limits daily activities to athletes with PVCD only associated with exercise is far from scientifically sound.
While the evidence for serious psychiatric conditions among athletes with exercise-related PVCD is lacking, certain personality traits are common among most of the affected individuals. The prototypical individual with exercise-related PVCD is a young woman who is a highly competitive athlete, success oriented, and intolerant of failure.3 These attributes are often shared by her parents and permeate the individual's activities outside of athletics. In the case series of Landwehr et al,5 all adolescents for whom they had data were described as “straight A” or “4.0” students.
Anxiety may also be a contributing factor. Our patient's psychological profile was quite consistent with the prototype and helped to raise our initial index of suspicion for PVCD. We had the additional advantage in that she had spent a semester as an athletic training student at the high school. This gave us an opportunity for better insight into her personality traits than is typically afforded an athletic trainer and team physician.
Vocal-cord dysfunction is a rare disorder, although the incidence is likely higher than reported. Athletic trainers should be aware of the disease and monitor all athletes with EIA for continuing symptoms and compliance with prescribed medications. The diagnosis of PVCD requires an initial high index of suspicion, which may be heightened if important historical information is provided to the attending physician. A timely and proper diagnosis of PVCD can alleviate an athlete's symptoms, allowing the player to perform optimally and avoid unnecessary medications. A thorough understanding of PVCD permits the athletic trainer to aid in the athlete's understanding of the disorder and to assist with treatment.