Treatment with the antiepileptic drug pregabalin (Lyrica) appears to relieve symptoms among patients with laryngeal sensory neuropathy, researchers reported at the 88th annual meeting of the American Broncho-Esophagological Association.
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October 2008Of the 12 patients in the study, 10 improved with pregabalin, said David L. Sycamore, MD, a resident in otolaryngology at Indiana University School of Medicine in Indianapolis, in his oral report at the meeting, held in conjunction with the Combined Spring Otolaryngology Spring Meeting.
Treatment with pregabalin appears to be an effective option for laryngeal sensory neuropathy, Dr. Sycamore said. Future prospective studies are needed to compare outcomes between pregabalin and other established treatments.
Researchers reviewed hospital records for patients who were treated for laryngeal sensory neuropathy from February 2006 through October 2007, and, after receiving approval from the Indiana University School of Medicine institutional review board, performed a retrospective study based on a patient chart review, Dr. Sycamore said in discussing his results. The study included all patients who presented to the Indiana University Clinic for Voice, Swallowing, and Airway Disorders who were diagnosed with laryngeal sensory neuropathy suggested by history and examination, and patients who received empiric treatment with pregabalin.
Pregabalin as Treatment for Neuropathy
This study introduces pregabalin as an alternative treatment for this disorder, Dr. Sycamore said.
Pregabalin is a gamma analog that binds to the calcium channel in the central nervous system, which, in turn, inhibits the releases of certain neurotransmitters. The medication is currently indicated for treatment of partial seizures, postherpetic neuralgia, and diabetic peripheral neuropathy. There have been no previous studies investigating pregabalin use in laryngeal sensory neuropathy, he said.
Dr. Sycamore noted that neuropathy can affect any part of the body. It can involve motor function, sensory function, or both, he said. Motor impairments can involve dysfunction or lack of function. Sensory problems can manifest as insensitivity, paresthesia, or pain.
Some examples of neuropathy that are common to the head and neck region are Bell’s palsy, idiopathic vocal fold paralysis, trigeminal/glossopharyngeal neuralgia, and laryngeal sensory neuropathy. The etiologies of neuropathy are variable and include viral/autoimmune, ischemic, and traumatic causes.
He acknowledged that treatment of laryngeal sensory neuropathy is a difficult problem because of challenges in diagnosing the complaint-usually globus sensation or the feeling that there is a lump in the throat, despite the lack of a mass. He said patients often complain of a cough or a need for throat-clearing despite being free of colds or infections.
Diagnosis and Treatment of Laryngeal Sensory Neuropathy
He said that history of onset is an important part of diagnosing laryngeal sensory neuropathy. It typically presents as an acute onset that the patient can clearly remember, he said. Frequently the patient will describe a laterality of symptoms, such as a globus sensation. Typical symptoms include globus sensation, chronic cough, odynophonia, and odynophagia. Exam findings are often lacking in this diagnosis, though at times you may find vocal cord hypomobility or paresis. These findings may support the diagnosis, but can also result from other causes. There is no proven objective testing for diagnosing laryngeal sensory neuropathy at this time. Because of this, a diagnosis of laryngeal sensory neuropathy is primarily based on history.
Current common treatments of laryngeal sensory neuropathy include the use of gabapentin and amitriptyline, but those treatments tend to be limited due to sedation and tolerance to the medication, he said.
Details of Pregabalin Study
In the study, doctors collected data on patient demographics, their chief complaint and precipitating factors, treatment, and response. Patients rated their symptoms on a scale of 0 to 5 before and after treatment, Dr. Sycamore explained. We compared the pre- and post-treatment scores of only their chief complaint-globus sensation, throat discomfort, chronic throat clearing, or chronic cough-for this study. We also tracked adverse side effects, drug tolerance, and the ability to wean off the treatment.
The mean age of the patients was 53 years. All patients had acute onset of globus sensation or cough or throat clearing.
Dr. Sycamore said that in four of the patients, the incident of laryngeal sensory neuropathy followed an upper respiratory infection; in another four patients, symptoms followed surgical intervention and intubation. The severity of the patients’ chief complaint was tracked before and after treatments. Of the 10 patients who responded to pregabalin, the pretreatment complaint score was 4.4. After treatment of at least one month, the mean score was 2.1.
In our study we did not find evidence of drug tolerance with pregabalin, Dr. Sycamore said. Sedation was severe enough in two cases to cause patients to discontinue therapy.
Six patients reported improvement at a dose of 150 mg twice a day. Two of these patients required increased their dosing from an initial dose of 75 mg twice a day. The rest of the patients who responded reported improvement on either 75 mg twice a day or 75 mg three times a day. Eight patients continued to take pregabalin for symptom management throughout the 15-month duration of the study, he said.
Implications
Our results indicate that pregabalin is highly effective in treatment of laryngeal sensory neuropathy, improving the chief complaint of globus discomfort, cough, or throat clearing, Dr. Sycamore said. Effective symptom control can be obtained with 75 mg twice a day; however, at least 20 percent of patients required 150 mg twice a day.
Among patients who can tolerate pregabalin, treatment of neuropathy has been shown to be effective for at least 15 months, said Suzan Streichenwein, MD, a private practice psychiatrist in West Palm Beach, FL. Several of these antiepileptic drugs appear to have effectiveness in treatment of various other neuropathies as well.
This study would give patients another option for treating a condition that can be a problem for the patients, as well as those who live or work with that individual, said Dr. Streichenwein, a former researcher in development of pharmaceuticals and Assistant Clinical Professor of Psychiatry at the Baylor College of Medicine in Houston, who is board certified in psychiatry and neurology.
She cautioned, however, that pregabalin may cause somnolence or balance difficulties among older individuals, and doctors should consider the possibility of that type of adverse event in treating older populations than the group reported by Dr. Sycamore.
©2008 The Triological Society
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