Chronic Cough (Laryngeal Sensory Neuropathy)

There are patients with a chronic dry cough that seems to defy all explanation and resist all the usual standard treatments. Some of these patients have coughed for more than ten years resulting in frustration not only in terms of treatment, but diagnosis. Often, patients are told their cough is due to reflux, allergy, asthma, infection, aspiration, virus, etc and undergo numerous exams and studies including pulmonary function tests, chest x-rays, reflux studies, barium swallows, upper endoscopy, CT scans, MRI scans, etc. Even all medications known to cause a cough as a side effect (ie, ACE Inhibitors) are removed to no avail. More often than not, all these medical studies come back normal. Furthermore, proposed treatments with antibiotics, proton pump inhibitors, allergy medications, cough suppressants, steroid inhalers, etc are not successful. Eventually, some are even told it's all in their head (psychogenic cough, habit cough, tic cough, etc) or idiopathic.

A typical patient with the chronic cough is described as follows:

Started during or after recovering from a viral laryngitis and/or upper respiratory infection
Dry cough
Cough occurs due to no perceivable reason...perhaps only a tickle
Cough may occur several times an hour to even as often as several times a minute. Must be distinguished from whooping cough (severe attacks of a choking cough that lasts 1-2 minutes often with near vomiting and appearance of suffocation-watch video).
Cough does not seem to get better with time (months or even years)
All diagnostic studies performed come back normal
Endoscopy of the voicebox is normal (this exam will be performed on the first visit to ensure that there is no anatomic reason for the cough)

If this description sounds like you, you may have chronic cough due to laryngeal sensory neuropathy (aka, sensory neuropathic cough, vagal neuropathy, etc). What does this mean? Essentially, this means that the nerve that provides sensation to the voicebox and is responsible for triggering the cough reflex has been injured, usually by a virus. When this happens, the nerve's level of sensitivity before it triggers the cough reflex becomes markedly reduced; in other words, it becomes hyper-sensitive. This situation is akin to the elevated sensitivity of the skin producing pain even with the lightest touch after healing from a bad burn, even if the skin appears completely normal. Other related forms of such sensory neuropathy include diabetic neuropathy, post-herpetic neuralgia, phantom limb pain, etc.

Normally, the nerve recovers its normal level of sensitivity and the cough resolves. However, in some patients, the nerve does not recover and a persistent chronic cough results. In this scenario, the best medications are those that "calm" the nerve down. Such medications include amitriptyline (elavil), nortriptyline (pamelor, aventyl), tramadol (Ultram), or gabapentin (neurontin). If you are well-versed in medications, you will realize that these are the same medications used to treat various peripheral neuropathies listed in the prior paragraph. Please note that for a given patient, one medication may work better than the other which may not work at all. Trial and error is unfortunately necessary. Also, these medications will NOT help a cough due to an active infection (cold, flu, pneumonia, bronchitis, etc).

With careful guidance with these medications, the cough signficantly improves and even completely resolves. The medications are taken for 3 to 6 months after which it is slowly tapered down. Of note, in certain rare situations, vocal cord dysfunction, globus pharyngeus, and chronic throat-clearing are related disorders treated in a similar manner (once reflux and other medical disorders are ruled-out).

In extremely rare situations, botox injections into the vocal cords may help should the medications be found ineffective.

If laryngeal sensory neuropathy is affecting your quality of life, please contact our office for an appointment. PLEASE HAND-BRING the most recent reports and studies listed below (show to your physicians):

GI
- EGD
- Barium swallow
- 24 hour pH probe
- Response after maximum reflux medication treatment for 3 months
  - Proton pump inhibitor twice a day (30 minutes before breakfast and dinner) AND
  - Zantac 300 mg at bedtime AND
  - Reglan 10 mg 4X per day
Allergy
- Allergy testing
- If positive, allergy injection response report
Pulmonary
- Pulmonary function test with methacholine challenge
- Bronchoscopy with lavage cultures
- CT chest
- Response to asthma medications

Too often if you leave it up to each individual medical office to mail/fax the records, it doesn't happen in time for your visit which would waste your time and money. These records are ESSENTIAL and each of these studies should (generally speaking, though there are exceptions) be done prior to determining whether you may or may not have laryngeal sensory neuropathy.

To find a physician local to where you live who may be familiar with this disorder, click here.

References

Chronic cough as a sign of laryngeal sensory neuropathy: diagnosis and treatment. Lee B, Woo P. Ann Otol Rhinol Laryngol. 2005 Apr;114(4):253-7. Link
Gabapentin in the Treatment of Intractable Idiopathic Chronic Cough. Mintz S, Lee JK. Am J Med. 2006; 119(5):e13-15. Link
Laryngeal Neuropathy as a Cause of Chronic Intractable Cough. Mishriki YY. Am J Med. 2006; 119(5):e5. Link
Sensory neuropathic cough: a common and treatable cause of chronic cough. Bastian RW, Vaidya AM, Delsupehe KG. Otolaryngol Head Neck Surg. 2006 Jul;135(1):17-21. Link
Effectiveness of amitriptyline versus cough suppressants in the treatment of chronic cough resulting from postviral vagal neuropathy. 2006. Jeyakumar A, Brickman TM, Haben M. Laryngoscope 116(12):2108-2112. Link
The irritable larynx syndrome. Morrison M, Rammage L, Emami AJ. Journal of Voice. 1999;13:447-55. Link
Vagal neuropathy after upper respiratory infection: a viral etiology? Amin MR, Kaufman JA. American Journal of Otolaryngology, 2001;22(4):251-256. Link
Cough and paradoxical vocal fold motion. Altman KW, Simpson CB, Amin MR. Otolaryngology-Head & Neck Surgery. 2002;127(6):501-11. Link
Botulinum Toxin A: A novel adjunct treatment for debilitating habit cough in children. Sipp JA, Haver KE, Masek BJ, Hartnick CJ. ENT Journal 2007;86(9):570-572. Link

News Article on This Topic

Dr. Chang was featured in a regional quarterly publication addressing Laryngeal Sensory Neuropathy. Click here to read the article (first 2 pages).

Any information provided on this Web site should not be considered medical advice or a substitute for a consultation with a physician. If you have a medical problem, contact your local physician for diagnosis and treatment.