Office-Based Superior Laryngeal Nerve Block for Treatment of Neurogenic Cough

Office-Based Superior Laryngeal Nerve (SLN) Block for Treatment of Neurogenic Cough

The purpose of this study is to evaluate if office-based injection of a local anesthetic/steroid combination at the area of one superior laryngeal nerve can decrease cough frequency and alleviate symptoms of chronic cough in patients with neurogenic cough.

Neurogenic cough is a chronic cough without a clear cause. It is thought to be related to irritation of a nerve that goes to the larynx (voice box). This can happen after a viral upper respiratory infection. Current treatment uses therapy or medications taken by mouth. Those medications can be sedating and not well tolerated. An alternative approach would be to perform an injection "nerve block", which is commonly done for other nerve disorders such as around the spine. This may help people with neurogenic cough also. We studied this recently in a small group of patients and found that patients had improvement in their cough symptoms (Simpson 2018). It would be helpful to study this in a larger group of patients using more methods of evaluating cough symptom severity.

Inclusion Criteria:

• Age 18 years or older

• Ability of patients to speak and understand English

• Ability for patients to consent for themselves

• Cough for 8 weeks or greater, with suspected sensory neuropathic etiology of the cough. Inclusion based on history of preceding upper respiratory infection or other symptoms suggestive of irritable larynx such as cough in response to temperature changes, odors, scents/perfumes, tickle, irritation in the throat/paralaryngeal region, or talking.

• Persistent cough despite treatment of ALL the major contributors of cough (items listed below would be done as part of a standard clinical workup for chronic cough and are not done specific to this study):

  • Reflux disease treatment with one of the following: failure of two months of PPIs OR negative pH study
  • Asthma: lack of response to at least one month of steroid inhaler/bronchodilator OR normal PFTs/negative methacholine challenge + negative CXR/CT
  • Upper airway cough syndrome/Allergic disease: lack of response to at least one month of antihistamines/decongestants/nasal steroids OR negative allergy testing (skin or serum) OR lack of response to at least one year of immunotherapy/allergy shots

Exclusion Criteria:

• Age less than 18 years
• Patients unable or unwilling to provide informed consent
• Known etiology to cough other than sensory neuropathy (e.g., reflux disease, asthma, allergic rhinitis, chronic obstructive pulmonary disease)
• Addition of new neuromodulators at the time of the injection. Patients who were already being treated with neuromodulators for their cough (e.g., gabapentin, amitriptyline) will not be excluded provided their dose remains constant.
• Nissen fundoplication within the last year
• Smoking history within last 5 years
• Allergy to bupivacaine or Kenalog-40