Treatment. To both confirm the diagnosis and treat the patient in a rapid, practical fashion, a trial of a neuromodulating agent such as pregabalin or gabapentin can be employed.6-9 A study identifying 28 LSN patients found symptomatic relief in 68% of patients taking gabapentin 100 to 900 mg/d.2 In another study, 12 LSN patients given pregabalin found relief after a 1-month regimen.1 Another study of 12 patients showed amitriptyline hydrochloride and gabapentin provided a positive response in 2 months, and the addition of reflux precautions and acid-suppression therapy was helpful.9 Finally, a group of 32 patients trialed on 3 different medications (amitriptyline, desipramine, and gabapentin) found similar efficacy among the 3.6
Another option. Aside from medications, botulinum toxin type A has been shown in a case series to directly decrease laryngeal hypertonicity and possibly reduce neurogenic inflammation and neuropeptide-mediated cough.10 Another study found that 18 patients with neurogenic cough who received superior laryngeal nerve blocks had cough severity index scores decrease from an average of 26.8 pretreatment to 14.6 posttreatment (P < .0001).11
Our patient agreed to a trial of gabapentin 300 mg once a day, with titration up to a maximum of 900 mg tid. When the patient returned to the clinic 4 months later, he reported that when he reached 300 mg bid, the cough completely resolved.
THE TAKEAWAY
A persistent cough with minimal identifiable triggers is a huge disruption to a patient’s life; having to visit multiple specialists before receiving a diagnosis compounds that. In our patient’s case, the process took 5 years, which underscores how important it is that LSN be considered in the differential diagnosis. Since this is generally a diagnosis of exclusion, it is important to take a careful history of a patient with a chronic cough. If LSN seems likely, trialing a patient on neuromodulating medication is the next best step, with dose titration if necessary.
CORRESPONDENCE
Selena R. Pasadyn, 675 West 130th Street, Hinckley, OH, 44233; pasadys@ccf.org