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The Chronic Cough (a.k.a. habit cough, tic cough,
psychogenic cough, irritable larynx syndrome)
There are patients with a mysterious chronic dry cough (longer than 6 months) 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 nfection, aspiration, virus, etc and undergo numerous exams and studies including pulmonary function tests, chest x-rays, reflux studieupper endoscopy, CT scans, MRI scans, etc. Even all medications known to cause a cough as a side effecInhibitors and Angiotensin Receptor Blockers) are removed to no avail. More often than not, all these medical studies come back normal. Furthermore, proposed treatments with antibiotough suppressants, steroid inhalers, etc are not succemay even be performed which also fails to improve the cough. 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 fr(severe attacks of a choking cough that lasts 1-2 minutes often with near vomiting and appearance of suffocation.  Cough does not seem to get better with time (months or even years)  All diagnostic studies performed come back normal  of the throat and voice box is normal (this exam will be performed on the first visit to ensure that there is no anatomic reason for the cough). Such anatomic factors that may trigger a cough include an elongated uvula as well as large tonsils. 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 voice box 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), desipramine, pregabalin (lyrica), 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). Please note: MUST be performed before this treatment is initiated as laryngeal
sensory neuropathy is a diagnosis of exclusion.
With careful guidance with these medications, the cough significantly 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 situationsare related disorders treated in a similar manner (onceand other medical disorders are ruled-out or thoroughly managed). Patients need to keep in mind that it is not unusual that a patient may have SEVERAL factors of cough as well, all of which need to be treated in order to resolve a persistent cough. For example, reflux and allergies may be present as well as laryngeal sensory neuropathy. Because this disorder results in a hyper sensitized larynx, problems with reflux and allergies which ordinarily would not cause a cough in normal patients will now cause a persistent cough. In other words, though allergy testing may reveal only mild allergies and 24 hour pH impedance study may show reflux episodes within normal range, these "mild" problems now need to be treated aggressively along with the neuropathy. The lack of treatment for each and every known cause of cough (even if mild) is the most common reason why treatment of laryngeal sensory neuropathy fails with neuropathic medication. To reiterate. laryngeal sensory neuropathy is a hyper sensitized larynx. In this hyper sensitized state, even a little bit of reflux or allergies will trigger a cough which normally would not occur in a normal larynx. Each and every one of these conditions needs to be treated. In extremely rare situatiinjections into the vocal cords may help should the medications be found ineffective. If it is a child with a chronic cough, there is a VERY rare disorder calle(Pediatric
Autoimmune Neuropsychiatric Disorder Associated with Streptococcus) where strep infections can
trigger motor tics including chronic cough (oremingly overnight. If there is concern
for this particular disorder, an evaluation with a pediatric neurologist may be warranted.
If you are a musician playing a wind or brass instrument. your chronic cough could be due to your
instrument! Germs have been found inside such instruments that can get inhaled into your lungs
causing a pneumonitis resulting in chronic cough.
If laryngeal sensory neuropathy is affecting your quality of life, pleaseour office for an appointment. PLEASE HAND-BRING the most recent reports and studies listed below (show to your
physicians). Even better, please MAIL the records a few weeks before your visit so they can be
reviewed prior to your visit to save time.
These records are ESSENTIAL and each of these studies should be done (generally speaking,
though there are exceptions) prior to determining whether you may or may not have laryngeal
sensory neuropathy.
 Vitamin B12 supplementation if deficient
 Bordetella serum titers
 Prior Blood Lab Work (C-ANCA, ESR, CA, CBC)
 GI Workup
o EGD (Evaluate for esophageal pathology. In rare cases, mucosal ulcers have been
found hypothesized to irritate the recurrent laryngeal nerve, found alongside the esophagus, resulting in cough). o Barium swallow (Evaluate for esophageal motility problems as well as
o 24-Hourand pH monitoring with
manometry (Evaluate foas well aease note that BRAVO
and other types of pH studies are NOT good enough.
o Response after maximumtreatment
 Allergy Workup
o CT Sinus scan (Evaluate for subclinical chronic sinusitis)
o Allergy testing (Evaluate for allergies). If positive, allergy injection response report
 Pulmonary Workup
o Pulmonary function test with methacholine challenge (Evaluate for reactive airway
o Bronchoscopy with lavage cultures (Evaluate for subclinical pulmonary
o CT Chest scan (Evaluate for lung masses too small to be seen on Chest X-ray)
o Response to asthma medications
o Sleep Study to evaluate for obstructive sleep apnea

Source: http://southlouisianamd.com/uploads/SLENT_ENT_Handout_-_Chronic_Cough.pdf