Differentiating asthma from vocal cord dysfunction
CaitlinFiorillo, M.D. and Nancy M.Bauman, M.D., FACS, FAAP
Focus on Subspecialties
Paradoxical vocal fold motion (PVFM), also known as vocal cord dysfunction, refers
to recurrent bouts of adduction (closure) of the vocal folds during inspiration, when
the vocal folds should be abducted (open). The resultant stridor and air hunger sensation
appears life-threatening to the patient, caretakers and even to health care providers
not familiar with the condition.
PVFM symptoms often are mistaken for severe asthma or laryngospasm, and the average
time to diagnosis ranges from months to years (Smith B, et al. Am J Otolaryngol. 2017;38:230-232).
Awareness of the characteristics of PVFM among primary care and emergency department
(ED) providers will hasten diagnosis and improve management.
Characteristics of PVFM
Previously, PVFM was thought to be a conversion disorder but now is considered a primary
functional disorder. The precise incidence and etiology are unknown, but pediatric
PVFM usually is considered a stress-related condition.
Although affecting either gender, it usually presents in preteen and teenage females
with a predilection for scholastic and athletic overachievers. Episodes can happen
any time, even when asleep, but sentinel events often occur during an extreme sporting
event, accounting for PVFM’s frequent misdiagnosis as exercise-induced asthma.
Parents recount frightening details of their child’s noisy breathing and acute dyspnea
that often prompts an ED visit. Patients describe globus sensation, throat tightness
and an alarming sense of air hunger during episodes. Episodes are self-limited and
in most cases resolve in minutes prior to arrival to an ED.
A flattened inspiratory loop on pulmonary function testing is highly suggestive of
PVFM. The gold standard of diagnosis, though, is flexible fiberoptic laryngoscopy
during an acute episode where paradoxical vocal cord adduction during inspiration
Since breathing is normal between episodes, both studies often are nondiagnostic,
and history remains the mainstay of diagnosis.
Eighty percent of PVFM cases are mistaken for asthma (Smith B, et al. Am J Otolaryngol. 2017;38:230-232). However, unlike expiratory wheezing that is characteristic of asthma,
the stridor of PVFM is high-pitched, inspiratory and unresponsive to bronchodilators.
During PVFM episodes, pulse oximetry, blood gas values and chest X-rays are normal
unless another underlying disease is present.
The relative rarity of PVFM in the primary care setting and its seemingly life-threatening
nature prompts a battery of unnecessary diagnostic tests and treatments. In a recent
patient-reported outcome study, nearly all participants with PVFM reported initial
misdiagnosis with another condition, usually asthma, and underwent a mean of 3.7 unnecessary
diagnostic studies prior to referral to an otolaryngologist or pulmonologist, who
established the diagnosis (Yibrehu B. American Society of Pediatric Otolaryngology
Spring Meeting, May 2019).
In the same study, a variety of ineffective treatments were prescribed, including
anti-reflux and allergy medications, anticholinergics, breathing treatments and steroids,
each of which more than 50% of participants reported using without significant efficacy.
Fortunately, PVFM is a treatable condition. Gold standard treatment is speech and
behavioral therapy administered by a speech and language pathologist (SLP) ideally
in conjunction with an otolaryngologist.
Respiratory exercises are taught, including abdominal breathing and strategies that
reflexively open the glottis like sniffing and breathing through pursed lips. Biofeedback
where patients watch their vocal cord activity on a monitor during flexible fiberoptic
laryngoscopy demonstrates the efficacy of these maneuvers and empowers patients to
prevent or abort PVFM episodes.
Comorbidities, including reactive airway disease and reflux disease, may exacerbate
PVFM; however, with SLP intervention alone, over 90% of patients improve (Sullivan
MD, et al. Laryngoscope. 2001;111:1751-1755).
While breathing exercises are critical for short-term control, stress management is
paramount for long-term PVFM management. Although two-thirds of patients report bouts
of PVFM even two years after initial diagnosis, the stress associated with episodes
significantly decreases when improved coping mechanisms are used (Yibrehu B. American
Society of Pediatric Otolaryngology Spring Meeting, May 2019).
In a small number of patients, brain abnormalities, such as Chiari malformation, can
cause PVFM and should be considered in patients who are refractory to treatment or
have other neurologic signs.
With enhanced recognition of PVFM among primary care and ED providers, the diagnosis
and management of this enigmatic condition should be improved. Prompt referral to
an SLP and otolaryngologist specializing in PVFM management is indicated to teach
breathing and voicing exercises and emphasize the need for stress management.
Dr. Fiorillo, a post residency training member, and Dr. Bauman are members of the
AAP Section on Otolaryngology-Head and Neck Surgery.