return to: Speech Pathology Protocols; The Evaluation of Stridor in Pediatric Patients

Definition: Inappropriate adduction (closure) of vocal cords

1. Classically occurs with inspiration constricting the airway causing stridor
2. May occur throughout respiratory cycle
3. VCD defined as "a paradoxical movement of the vocal cords' - with a hyperfunctional laryngeal reflex which results in adduction (coming together) of the vocal cords with resultant airflow limitation (Porsbjerg 2017, Kenn 2012)

Differential diagnosis

1. Bilateral vocal cord paralysis, abductor paralysis or unilateral paralysis with a narrow glottic aperture (see: Bilateral Vocal Cord Paralysis) - Bernoulli effect during inspiration (passive adduction) may confuse diagnosis; need to see abduction to rule out either
2. Posterior glottic stenosis (interarytenoid web,scar or arytenoid fixation - see: Posterior Glottic Stenosis)
3. Subglottic or tracheal stenosis (see: Subglottic stenosis)
4. Association with asthma - "VCD' reported to be present in 32-50% of patients with difficult asthma (Tay 2016, Low 2011)
5. Irritable larynx -with conditions leading to increased laryngeal sensitivity such as
   1. Postnasal drip Medical Management of Sinusitis
   2. Gastroesophageal reflux Esophageal Reflux Precautions
   3. Respiratory infections 
6. As per Porsbjerg et al (Porsbjerg 2017) "a large proportion of patients appear to have a functional component, with pathopsychological traits such as signs of conversion disorder"
7. As per Shembel et al (Shembel 2017) "'consensus lacks among clinicians regarding clinical criteria for diagnosis" of ELBD = episodic laryngeal breathing disorder
8. As per Forrest et al (Forrest 2012) Although PVCM (paradoxical vocal cord motion) may be a psychological disorder, there are different forms which they divided into "primary, or psychological, and secondary" - with the secondary form consists of medical disorders divided into irritable larynx syndrome and neurologic disorders.

Standard testing protocols not universally adopted as yet (Forrest 2012)

1. General Features test
   1. Normal complete abduction of vocal cords should be seen at some point in exam to rule out vocal cord paresis/paralysis
      1. Flexible fiberoptic laryngoscopy at bedside (adults) vs direct laryngoscopy in operating room under spontaneous ventilation (consider for pediatric patients to rule out other causes of obstruction)
      2. Dr. Bastian demonstrates a simulated period of laryngospasm on a website accessible by searching for "laryngospasm and bastian"
   2. Classically presents with intermittent shortness of breath
      1. Often provoked by exertion or chemical exposures
      2. Commonly misdiagnosed as asthma
      3. Attacks typically do not respond to medical therapy targetted to reactive airway disease (beta antagonists)
      4. Rarely may be severe enough to provoke treatment with intubation or tracheotomy
2. Flexible fiberoptic transanasal laryngoscopy (see: Flexible Fiberoptic Laryngoscopy (written instruction))
3. Exercise laryngoscopy

Key findings from a key prospective study including psychologic evaluation (Forrest 2012)

1. Primary (non-organic) PVCM  
   1. Generally not life-threatening
   2. 75% of patients with PVCM are "primary" - represent a somatoform disorder
      1. Somatoform disorders are psychological difficulties with symptoms of a physical disorder unexplained by a medical condition
      2. Conversion or somatization disorder (more common) 
         1. unconsciously produced deficit in motor or sensory functioning, always preceded by a psychological stressor; females>males
         2. Conversion - common; may only present with neurological (sensory/motor) symptoms
         3. Somatization - less common;  diagnosis requires a mix of pain symptoms, gastroenterological symptoms, sexual/reproductive symptoms and neurological symptoms
      3. Factitious or malignering (less common)
         1. consciously produced deficit in motor or sensory functioning; males>females
         2. Factitious - feigning of symptoms to simulate a disease with a goal for attainment of patient role without external incentive
         3. Malingering - feigning of symptoms to simulate a disease with external incentive as motivation (eg. monetary gain, drug seeking), symptoms improve once objective attained
      4. Psychological testing (including MMPI) by Forest et at 2012
         1. Abnormal in 75% with PVCM
         2. Abnormalities: highly elevated hypochondriasis scale, highly elevated hysterical scale. (not elevated on anxiety scale)
   3. After initial evaluation and exam, recommend referral to speech and language therapist (SLP) who can provide various methods to counsel patients, such as:
      1. Sniff in through the nose - mandates vocal cord abduction moreso than mouth-breathing
      2. "Pant like a pup"
      3. Diaphragmatic breathing
      4. Education on function and importance of larynx
   4. Consider heli-ox to abort acute episodes 
2. Secondary (organic) PVCM 
   1. Less common
   2. Potentially life-threatening
   3. 25% of PVCM patients have normal psychological testing - divide this group into Neurologic / Hyperreactively
      1. Laryngeal Hyperreactivity
         1. Irritable larynx syndrome
            1. Contributing factors: GERD, allergic laryngitis, laryngeal sicca, recent intubation, laryngeal candidiatsis, untreated OSAS, tobacco, in halation exposure
            2. Rx: Behavioral and medical management designed to reduce laryngeal irritation
      2. Neurologic Disorders
         1. Focal respiratory dystonia (rare) / Multiple sclerosis flares / autonomic dysfunction (Shy Drager syndrome)
         2. Laryngeal sensory neuropathy (possibly a factor in PVCM)
         3. Brainstem compression 
            1. suspect in infants
            2. suspect in presence other intracranial processes/symptoms (Arnold-Chiari, aqueduct stenosis, hydrocephalus),
            3. suspect when associated with vagal dysfunction (VPI, nasal regurgitation, dysphagia, aspiration, GERD)
            4. Good results with surgical decompression 
         4. Cortical or UMN injury
            1. stroke
            2. static encephalopathy - older children (developmental delay, sialorrhea, hypertonia)
         5. LMN injury affecting vagal nuclei or RLN 
            1. eg. ALS, myasthenia gravis, medullary infarction
         6. Movement disorders
            1. eg. dystonia, tremors, hyporeflexia
               1. Parkinsonism
               2. Select candidates may benefit from botox to thyroarytenoids

Management

1. Attention to avoid irritants by managing reflux, sino-nasal complaints and the environment
2. Intervention by speech pathology 
   1. Identified by Kramer et al (Kramer 2017) as helpful not only for the vocal cord closure problems, but also in decreasing need for asthma medications in those diagnosed with asthma
   2. "Laryngeal control therapy" coupled with educating the patient about anatomy and physiology in the course of performing transnasal flexible laryngoscopy was employed in this study
3. Severe airway obstruction as in the case depicted below of a laryngeal dystonia may be associated with life-threatening airway obstruction and may warrant tracheotomy
4. Botulinum toxin injection to the TA muscle has been reported as useful treatment in the small subset of refractory cases identified by deSilva et al (2019) in treating 13 patients over a 10 year period
   1. Mean dose of 2.55 units of  'botulinum toxin'per vocal fold (range 1.75-5.5 units) 
   2. 11/13 patients (84.6%) reported improvement in dyspnea; 2 of these 11 patients reported complete resolution of symptoms with one injection
   3. 2/13 patients did not have improvement following botulinum toxin injection underwent tracheotomy
   4. Other measures for treating this refractory group were identified by deSilva et al to include use of benzodiapines and heliox -reported as useful for short-term but not long-term therapy
   5. These investigators conclude that PVFMD is a highly variable disorder both in presentation and severity of symptoms - "further complicating the ability to make standardized recommendations for how to best treat a small subset of refractory PVFMD patients." 

References

Shembel AC, Sandage MJ, Verdolini Abbott K: Episodic Laryngeal Breathing Disorders: Literature Review and Proposal of Preliminary Theoretical Framework J Voice. 2017 Jan;31(1):125.e7-125.e16. doi: 10.1016/j.jvoice.2015.11.027. Epub 2016 Feb 24.

Porsbjerg C, Menzies-Gow A:Co-morbidities in severe asthma: Clinical impact and management.Respirology. 2017 May;22(4):651-661. doi: 10.1111/resp.13026. Epub 2017 Mar 22

Kenn K, Balkissoon R. Vocal cord dysfunction: what do we know? Eur. Respir. J. 2011; 37: 194–200.

Tay TR, Radhakrishna N, Hore-Lacy F, Smith C, Hoy R, Dabscheck E, Hew M. Comorbidities in difficult asthma are independent risk factors for frequent exacerbations, poor control and diminished quality of life. Respirology 2016; 21: 1384–90.

Low K, Lau KK, Holmes P, Crossett M, Vallance N, Phyland D, Hamza K, Hamilton G, Bardin PG. Abnormal vocal cord function in difficult-to-treat asthma. Am. J. Respir. Crit. Care Med. 2011; 184: 50–6.

Patel RR, Venediktov R, Schooling T, Wang B. Evidence-based systematic review: effects of speech-language pathology treatment for individuals with paradoxical vocal fold motion. Am. J. Speech Lang. Pathol. 2015; 24: 566.

Kramer S1, deSilva B1, Forrest LA1, Matrka L1.Does treatment of paradoxical vocal fold movement disorder decrease asthma medication use?Laryngoscope. 2017 Jul;127(7):1531-1537. doi: 10.1002/lary.26416. Epub 2016 Nov 15.

Maschka DA, Bauman NM, McCray PB,et al. A classification system for paradoxical vocal cord motion. Laryngoscope 1997;107:1429-1435

Forrest LA, Husein T, and Husein O: Paradoxical Vocal Cord Motion: Classification and Treatment. Laryngoscope, 122:844-853,2012

Forrest LA, Husein T, Husein O. Paradoxical vocal cord motion: classification and treatment. Laryngoscope2012;122:844–853

Bastian RW, Vaidya AM, Delsupehe KG: Sensory neuropathic cough: a common and treatable cause of chronic cough. Otolaryngol Head and and Neck Surg 2006; 135:17-21

Lee B, Woo P. Chronic cough as a sign of laryngeal sensory neuropathy: diagnosis and treatment. Ann Otol Rhinol Laryngol 2005;114:253-257

Mintz S, Lee JK. Gabapentin in treatment of intractable idiopathic chrnoic cough: case reports. Am J Med 2006;119:

deSilva B, Crenshaw D, Matrka L, and Forrest LA: Vocal Fold Botlinum Toxin Injection for Refractory Paradoxical Vocal Fold Motion Disorder  Laryngoscope, 129:808-811, 2019

Marcinow AM, Thompson J, Chiang T, Forrest LA, deSilva BW. Paradoxical vocal fold motion disorderi n the elite athlete: experience ata large division I university. Laryngoscope 2014;124:1425-1430