CONTENTS

• Overview
• Epidemiology
• Clinical presentation
• Bedside evaluation
• Differential diagnosis
• Acute evaluation – Diagnostics & approach
• Treatment
• Podcast
• Questions & discussion
• Pitfalls

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overview

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• Vocal Cord Dysfunction (VCD) is known by a variety of names, including:
  • paradoxical vocal fold motion
  • inducible laryngeal obstruction
  • functional upper airway obstruction
  • psychogenic upper airway obstruction
• VCD is a disorder marked by intermittent episodes of vocal cord contraction, particularly during inspiration.   This causes episodic dyspnea with stridor, which is classically confused with asthma.
• This is a functional disorder, which is typically associated with psychiatric comorbidities.
  • Patients are not malingering (not doing this intentionally).
  • There is true obstruction of the airway (in severe cases, hypercapnia can occur).

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epidemiology

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• VCD tends to occur in younger patients, with female predominance.
• Some patients have psychiatric comorbidities, but many do not.
• Asthmatic patients
  • Many patients also have asthma, creating a diagnostically confusing situation.
  • It is possible to simultaneously have bronchospasm and vocal cord dysfunction.
• Post-extubation
  • VCD may be more prolonged than laryngospasm.
  • Nasolaryngoscopy would be needed to differentiate this from laryngeal edema.

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clinical presentation

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pattern:  repeated episodes

• VCD may be triggered by various factors (e.g., stress, inhaled irritants, exercise, viral upper respiratory tract infection).
• The pattern of repeated exacerbations may mimic asthma or angioedema.
  • A history of multiple episodes of respiratory failure with intubation for unclear etiology may also suggest VCD.
• Often there is a history of an asthma evaluation or diagnosis, for example:
  • (1) Evaluation in pulmonary clinic for “asthma” with negative workup may suggest VCD (especially if asthma excluded using a methacholine challenge test).
  • (2) A failure to respond to treatment for “asthma” can also suggest VCD. (29517494)
  • (3) Occasionally a patient with VCD will be misdiagnosed with asthma and intubated.  Following intubation, airway pressures are normal and there is no auto-PEEP, which largely excludes severe asthma.  A history of multiple intubations for “asthma” with extubation the next morning suggests VCD.

primary feature is upper airway obstruction with stridor

• Stridor is audible to other people in the room (this really isn't a feature of asthma).
• Inspiratory stridor may be more common, but it can be both inspiratory and expiratory.
• Subjective features which may point towards VCD (rather than asthma):
  • Throat tightness as a primary complaint (rather than chest tightness).
  • Dysphonia (if present).
  • Dysphagia, globus sensation.

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bedside evaluation

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#1:  differentiate asthma from upper airway obstruction 

• Patients with VCD (or other upper airway problems) often present with easily audible stridor and/or expiratory wheeze.  This is often very dramatic and scary.   Alternatively, in patients with severe asthma this shouldn't be audible from across the room.  In fact, patients with severe asthma may have a totally quiet chest (even with a stethoscope).
• Listen over the patient's throat and also the lung bases:
  • VCD will often cause harsh, loud stridor which is loudest over the throat.
  • Asthma tends to cause more musical diffuse wheezing which is distributed more broadly throughout the chest.

#2:  look for characteristics of vocal cord dysfunction

• Patients with VCD may be able to pant or sing normally.   If present, this “sign” localizes the problem to the brain (specifically, this argues against angioedema or neck infections which may cause hoarseness).
  • Ask the patient to sing “Row Row Row Your Boat.”
  • Instruct the patient to open their mouth, stick out their tongue, and “pant like a dog.” (27522309)
• Use therapeutic breathing maneuvers (box below).
  • These may be both diagnostic and therapeutic.  Sustained improvement following these maneuvers would argue against ongoing structural pathology.

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differential diagnosis

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• Asthma
• Laryngospasm
• Angioedema/Anaphylaxis
• Epiglottitis
• Foreign body aspiration, tracheal stenosis
• Bilateral vocal cord paralysis
• Rapidly progressive form of airway obstruction (e.g., neck hematoma, deep neck space infection)

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acute evaluation – diagnostics & approach

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laryngoscopy during an episode

• This is the ideal diagnostic test if it is logistically feasible.   A major advantage is that it usually secures the diagnosis, which may clarify future management.
• Normal findings:
  • During inspiration vocal cords abduct (open)
  • During expiration vocal cords may adduct somewhat
• Findings in VCD:
  • Abnormal adduction of the vocal cords, especially during expiration.
  • Adduction typically involves the anterior vocal cords (which may leave only a tiny opening in the posterior portion of the glottis during inspiration).
  • Adduction occurs simultaneously with audible stridor (alternatively, if you are hearing stridor with the vocal cords open, then the obstruction is more distal in the airway).
• Differential diagnosis – can look a lot like:
  • Vocal cord paralysis
  • Laryngospasm
• Laryngoscopy is typically performed by ENT surgery (using a dedicated flexible laryngoscope).  Another option is bronchoscopy via the nares, but the bronchoscope is a larger than a fiberoptic laryngoscope and thus less comfortable.  Anyone can be trained in these skills, so this may also be done by emergency physicians if a nasolaryngoscope is in the department.

neck & chest CT scan

• This may be considered in some situations:
  • i) Patient is adequately stable to undergo a CT scan.
  • ii) Nasolaryngoscopy isn't readily available.
• CT scan is predominantly useful for excluding other causes of upper airway obstruction, such as:
  • Tracheal disease, including tumors or stenosis (which will be missed with nasolaryngoscopy).
  • Extra-tracheal compression (e.g., thyroid mass or goiter, peritonsillar abscess or other space-occupying lesions in the neck).
  • Epiglottitis

diagnostic/therapeutic trial of non-dissociating sedation

• 🛑  This is not supported by high-quality evidence and should only be performed very selectively by physicians with experience in airway management.
• This may be considered for moderate-severity cases (see flowsheet above).
• Reasonable options could be low-dose, rapid-acting benzodiazepine (e.g., IV midazolam) or IV haloperidol (Karaman et al. 2009).

diagnostic/therapeutic trial of ketamine

• 🛑  This is not supported by high-quality evidence and should only be performed very selectively by physicians with experience in airway management.  (27522309)
• Situations where this could be considered:
  • A diagnosis of VCD is strongly suspected.
  • The patient is unable to tolerate therapeutic breathing maneuvers (box above).
  • The patient is unable to tolerate laryngoscopy, or this option isn't available.
  • the patient appears very distressed and the alternative course of action is immediate intubation.
• Preparations should be made for intubation, with staff prepared to immediately intubate if necessary.
• Give a dissociating dose of ketamine (~1.5 mg/kg) slowly over 2-3 minutes.
  • Slow administration of ketamine avoids inducing apnea (which generally isn't dangerous but may confuse matters).
• One of two things should happen:
  • (a) If stridor/wheeze disappears immediately, this is diagnostic and therapeutic for VCD.  The patient should continue breathing, and eventually wake up like any patient sedated with ketamine.
  • (b) If the patient continues to have stridor/wheeze, then
    • The patient probably doesn't have VCD.
    • The patient probably has a life-threatening upper airway obstruction!
    • Do not paralyze the patient to facilitate intubation.
    • Consider an awake/fiberoptic intubation with double-setup.

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treatment

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• Anxiolysis may be helpful in the short term (e.g. using benzodiazepines).
• Reassurance
• Breathing exercises, such as nasal inspiration & pursed-lip expiration.  For details and additional exercises, see the box above.
• Heliox may provide some symptomatic relief.

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podcast

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questions & discussion

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To keep this page small and fast, questions & discussion about this post can be found on another page here.

• Many patients have both VCD and asthma.  Therefore, a history of either of these disorders doesn't eliminate the possibility that the patient will present with the other.  A thoughtful evaluation must occur every time the patient presents with dyspnea.
• A common pitfall is failing to consider VCD, leading to unnecessary intubation for management of “asthma.”
• If a patient is presumptively diagnosed with VCD but fails to respond to therapeutic sedation, re-consider whether the patient could have an alternative, life-threatening cause of upper airway obstruction.

Guide to emoji hyperlinks 

•  = Link to online calculator.
•  = Link to Medscape monograph about a drug.
•  = Link to IBCC section about a drug.
•  = Link to IBCC section covering that topic.
•  = Link to FOAMed site with related information.
•  = Link to supplemental media.

Going further

• Vocal Cord Dysfunction (NUEM Blog, John Andreck)