Bilateral Vocal Fold Paralysis Workup

Updated: Oct 20, 2020
  • Author: Joel A Ernster, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Workup

Laboratory Studies

Features of the history and clinical findings may suggest performance of the following studies:

  • Determination of serum K+ level

  • Determination of serum Ca+ level

  • Determination of glucose level

  • Antineutrophil cytoplasmic antibody (ANCA) test

  • Venereal disease research laboratory (VDRL) test

  • Determination of Lyme disease titer

  • Tuberculosis skin test

  • Uric acid test

  • Rheumatoid factor test

  • Antinuclear antibody (ANA) test

  • Determination of sedimentation rate

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Imaging Studies

Computed tomography (CT) scanning along the entire length of the vagus nerve from the skull base to the superior mediastinum may be necessary when no other cause is identified.

Magnetic resonance imaging (MRI) of the brain is not used as a routine study for bilateral vocal fold (cord) paralysis (BVFP).

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Other Tests

See the list below:

  • Pulmonary function tests: Although diagnosis is based on clinical findings, results of pulmonary function tests performed with flow volume loops help support a diagnosis of upper airway obstruction. Also, they are used to provide an indicator of the severity of the obstruction and to monitor change after treatment.

  • Acoustic analysis: Voice quality usually is not significantly altered. Assessing the voice with acoustic analysis as a baseline test can be helpful in evaluating recovery over time.

  • Neurologic tests: In certain patients, a neurologist may perform a more thorough examination to assess central disorders or neuromuscular disorders that may result in bilateral vocal fold (cord) immobility (BVFI).

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Diagnostic Procedures

Fiberoptic laryngoscopy

  • This procedure is the mainstay of clinical assessment.

  • Stroboscopic videolaryngoscopy may provide further information about vocal fold motion abnormalities when asymmetric mucosal wave patterns are identified.

  • Malingering or other psychogenic disorders may be identified by asking the patient to sniff or whistle, since these maneuvers work the abductors without the patient's volition.

Direct laryngoscopy

  • Examination of the posterior glottis and palpation of the arytenoid cartilages are essential steps in clarifying the nature of vocal fold immobility.

  • Cricoarytenoid (CA) joint ankylosis or IA scars that limit arytenoid motion are readily ascertained with direct laryngoscopy with the patient under general anesthesia and paralysis.

  • The subglottis, trachea, and main bronchi also may be examined to exclude subglottic stenosis, subtle infiltrative neoplasms, and other lesions along the entire airway.

    Direct laryngoscopic view of the larynx in a patie Direct laryngoscopic view of the larynx in a patient who with bilateral vocal fold immobility (BVFI) is shown. Palpation of the arytenoids revealed cricoarytenoid (CA) joint ankylosis. Close inspection of the interarytenoid space demonstrated interarytenoid scar. This condition is posterior glottic stenosis (PGS).

Laryngeal EMG

  • Ideally, laryngeal EMG is used to assess both the TA and the PCA muscles, and it should be performed with local anesthesia rather than general anesthesia. It has been performed in anesthetized children.

  • The TA muscle is approached through the cricothyroid membrane, while the PCA muscle is approached percutaneously by rotating the larynx.

  • The glottic compromise caused by bilateral vocal fold immobility (BVFI) may render EMG hazardous. Therefore, waiting until after tracheostomy to perform the test may be prudent in some cases.

  • In evaluating a patient with bilateral vocal fold immobility (BVFI), EMG provides the potentially useful information in the following:

    • Differentiating between fixation and paralysis

    • Differentiating between neurapraxia and axonal transection

    • Determining the presence of neuromuscular disorders or peripheral neuropathy

  • In the recording the EMG, correct timing is essential. EMG can be performed as soon as 2 days after injury to aid in differential diagnosis. As a prognostic tool, a baseline EMG should be obtained at least 30 days after injury and a second one should be obtained 30-60 days after injury. After 6 months, laryngeal EMG should be used only to differentiate between fixation and paralysis and not to assess neural regeneration.

  • Laryngeal EMG can predict poor recovery 90% of the time. [10]

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