The Efficacy of Superior Laryngeal Nerve Block for Neurogenic Cough: A Placebo-Controlled Trial.

OBJECTIVES

Chronic cough is a common and debilitating problem. The objective of this study is to assess the efficacy and safety of superior laryngeal nerve (SLN) block for neurogenic cough through a placebo-controlled, prospective trial.

METHODS

Patients were recruited in an outpatient tertiary care center. Inclusion criteria included a history consistent with neurogenic cough and age ≥ 18. Exclusion criteria included patients with untreated other etiologies of chronic cough (i.e., uncontrolled reflux) and current neuromodulating medication use. Patients were randomized into the treatment (1-2 mL of a 1:1 triamcinolone 40 mg: 1% lidocaine with 1:200,000 epinephrines) or placebo (saline) group and received two unilateral injections at approximately 2-week intervals. Outcomes were measured primarily by the Leicester Cough Questionnaire (LCQ) and a patient symptom log including a visual analog scale of cough severity.

RESULTS

17 patients completed the study, including 10 in the treatment group and seven in the placebo group. Eight (80%) patients in the treatment group reported improvement with at least one of the injections, whereas only 1 (14.3%) patient reported improvement in the placebo group (p < 0.0001). Average total LCQ scores increased in the treatment group from 10.09 to 13.15 (p = 0.03), with the most change occurring in the social domain. There was no statistically significant change in LCQ scores for the placebo group. There were no serious adverse events.

CONCLUSION

An SLN block is a safe and efficacious procedure for the treatment of neurogenic cough. Further studies are needed to optimize treatment protocol and assess long-term follow-up of patient outcomes.

LEVEL OF EVIDENCE

2 Laryngoscope, 133:3068-3074, 2023.