Thread by @nsrosenberg

Learned about Paradoxical Vocal Fold Dysfunction for the first time today, figured I'd share a few pearls!

#MedTwitter #MedStudentTwitter #pulmonary

PVFM is defined by recurrent closure of the vocal folds during inspiration. Remember to accurately breath, we need to normally have abducted vocal folds, cause otherwise there is no air passing distally.

Its etiology is not specifically known as a functional disorder, but some triggers are:
▶️Exercise
▶️Stress
▶️Airway Irritation via Trauma or Asthma
▶️Neurologic Disease
▶️GERD or Larygnopharyngeal Reflux
▶️Medications: EPS are associated (acute dystonia being a common link)

Symptoms of an Episode are mainly:
▶️Globus Sensation
▶️Throat TIghtness
▶️Air Hunger

As they tend to present in pediatric patients, children presenting often are brought in by worried parents, so addressing their worries might be the toughest aspect of this syndrome!

The approach to Dx is generally:

▶️PFT: flattened inspiratory loop is suggestive
▶️Laryngoscopy showing the above adduction is diagnostic

But like @rabihmgeha often mentions, in episodic conditions, you often see a patient post-episode and may not be able to diagnose it!

You can try to induce an episode with mannitol, histamine, or methacholine and then use the above methods, but there is not a lot of great evidence that these reliably induce an episode (goes back to multifactorial nature of this syndrome)

Differential Diagnosis: 80% of cases are misdiagnosed initially as asthma. The stridor here is high pitched, inspiratory, and nonresponsive to bronchodilators.

Also think laryngospasm, angioedema, and tracheal stenosis when you hear sudden onset stridor!

Acute Episode:

As commonly self limited, reassurance and CPAP are best during an episode. Interestingly, panting can relieve the stridor by initiating true vocal fold abduction

Some benefit shown with below treatments:
▶️Benzos: only acutely
▶️Heliox:
▶️Neb. Lido up to 4%

Long Term Management
▶️Gold Standard: Speech Therapy with abdominal breathing, pursed-lip breathing = opens the glottis
▶️Treating Comorbidities avoiding irritants is best
Long Term
▶️Ipratropium pre-exercise may prevent
▶️Botulinum toxin was effective in small case series

Summary:

PVFM is a multifactorial syndrome due to multiple triggers, presenting as acute recurrent episodes of stridor, air hunger, often self-resolving. Dx seeing adducted vocal cords and support during the episode, with chronic tx to keep the glottis unirritated and open!

uspharmacist.com/article/vocal-…

aappublications.org/news/2019/07/1…

ncbi.nlm.nih.gov/pmc/articles/P…

uptodate.com/contents/induc…