Supraglottic Botulinum Toxin Improves Symptoms in Patients with Laryngeal Sensory Dysfunction Manifesting as Abnormal Throat Sensation and/or Chronic Refractory Cough

Outcomes of a step-up approach to the treatment of neurogenic cough

INTRODUCTION

Neurogenic cough (NC) is thought to be related to sensory neuropathy in the hypopharynx and larynx. Defined as a cough persisting longer than 8 weeks refractory to standard therapy, it is a diagnosis of exclusion when other common etiologies (asthma, gastroesophageal reflux disease (GERD), medication side effects) are ruled out. It affects roughly 11 % of Americans and can negatively impact quality of life.

METHODS

Following institutional review board approval, we evaluated the medical records of adult patients seen at the University of Arizona's tertiary laryngology center from 2018 to 2023. Patients were included if their cough persisted for >8 weeks, and they either did not respond to prior proton pump inhibitor and asthma therapy or had GERD and asthma ruled out. These patients underwent a progressive escalation of therapy, which included neuromodulators with or without cough suppression therapy, superior laryngeal nerve (SLN) block, and laryngeal botulinum toxin injections. The primary outcome was patient-reported improvement in cough symptoms rated on a 1-5 scale: 1 = no response, 2 = mild improvement, 3 = moderate improvement, 4 = significant improvement, 5 = complete resolution.

RESULTS

A total of 56 patients were included. Mean (SD) age was 64.6 (14.8) years, and 66 % were female. Overall, 42 patients (75.0 %) responded to treatment. Among responders, 7 (16.7 %) experienced mild improvement, 14 (33.3 %) experienced moderate improvement, 17 (40.5 %) experienced significant improvement, and 4 (9.5 %) experienced complete resolution of their cough. 33 patients (58.9 %) were managed exclusively with neuromodulators ± cough suppression therapy; 27 responded, with an average response rating of 3.0 (SD = 1.2). 11 patients (19.6 %) failed medical therapy and underwent SLN block without subsequent botox treatment; 7 responded, with an average response rating of 2.5 (SD = 1.4). 9 patients (16.1 %) failed all previous therapies and underwent laryngeal botulinum toxin injections; 6 responded with an average response rating of 2.4 (SD = 1.3). The remaining 3 patients underwent cough suppression therapy alone, with 2 responding and an average response rating of 3.3 (SD = 1.7).

CONCLUSIONS

Neurogenic cough can be effectively treated with a stepwise multimodal approach, including neuromodulators, cough suppression therapy, SLN block, and laryngeal botulinum toxin injections.

Efficacy of Botulinum A Injection to the Laryngeal Adductor Compartment for Treatment of Cough

OBJECTIVES

Studies examining electromyography (EMG)-guided laryngeal onobotulinumtoxinA (BTxA) injection for chronic cough reveal promising efficacy, however, are limited by small cohorts and absent quantifiable outcomes. It further remains unclear if pulmonary disease limits efficacy, or if vagal motor neuropathy prognosticates response. We hypothesize BTxA injection results in qualitative improvement in cough, decrease in Cough Severity Index (CSI), no change in Voice Handicap Index-10 (VHI-10), and complication rates comparable to historical data. We also examine the correlation of pulmonary comorbidities and vocal fold hypomobility with treatment efficacy.

STUDY DESIGN

Retrospective review.

METHODS

Charts for patients receiving percutaneous adductor compartment BTxA injection for cough were reviewed for the binary outcome of patient-reported presence or absence of improvement. Generalized estimating equations regression models were used to analyze the change in CSI (ΔCSI) and the correlation of ΔCSI with qualitative outcomes. Multivariable analyses were used to examine correlation of vocal fold hypomobility and pulmonary disease with qualitative outcomes and ΔCSI.

RESULTS

Forty-seven patients underwent 197 BTxA injections from June 2012 to June 2022. A statistical proportion of 0.698 (0.599-0.813, p < 0.0001) or 69.8% of injections resulted in subjective improvement. Mean ΔCSI was -2.12 (0.22-4.02, p < 0.05), indicating overall improvement. With and without subjective improvement, estimated ΔCSI was -4.43 and +2.68, respectively (p < 0.0001). VHI-10 did not change (0.69, p = 0.483). Neither pulmonary disease nor vocal fold hypomobility correlated with subjective improvement or ΔCSI. Dysphagia occurred following 15 (7.6%) injections with no aspiration pneumonia or hospitalization.

CONCLUSIONS

BTxA injection to the laryngeal adductors may effectively treat cough with limited risk for serious complications.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1749-1756, 2024.