Christopher Chang talk about laryngeal sensory neuropathy and chronic cough also known as neurogenic or neuropathic cough

What LPR Has to Do with Laryngeal Sensory Neuropathy & Chronic Cough

 

Neuropathy means that nerves are somehow damaged.

Nerve damage happens quite often, especially in the nerves in the larynx which are very close to the surface. That is why they can easily be irritated and damaged. For example, they often are injured during an infection.

Originally, I started Refluxgate with the intention of helping people with laryngopharyngeal reflux (LPR) only.

However, I realized, that many of my readers also have signs of neuropathy. The symptoms of both diseases increase each other. If you have neuropathy, your nerves become more sensitive. You can have little reflux, but feel strong symptoms because of that.

During my investigation about neuropathy, I found the practice of Dr. Christopher Chang. He wrote an article about sensory neuropathic cough. That is chronic cough triggered by nerve damage. Other names for the disease are psychogenic cough and neurogenic cough. Chronic cough can be caused both by reflux and neuropathy. That is why these two conditions are easily mixed up during diagnosis.

I have interviewed Dr. Chang to find out more:

 

Interview with Dr. Christopher Chang about Laryngeal Sensory Neuropathy / Chronic Cough

Hello Chris, thank you for taking the time for this interview.

You wrote an article about the type of chronic cough that is caused by laryngeal sensory neuropathy. Why should LPR patients care about this topic?

Dr. Christopher Chang: There are many throat-related symptoms that seem similar to LPR, but they are actually caused by sensory neuropathy.

Laryngeal sensory neuropathy symptoms could include a globus sensation, constant throat tickle, constant throat clearing, a phlegmy throat sensation and other symptoms. A lot of these symptoms can easily be confused with LPR.

 

What is the most typical neuropathic symptom that is confused with LPR?

Chronic cough. A minority of patients experience a globus sensation, chronic throat clearing, phlegmy throat or a tickle in the throat. But most have a cough – sensory neuropathic cough.

 

Do symptoms manifest in and around the voice box only or can they also be higher up in the throat?

The symptoms could also be higher up, but typically, you find them around the voice box.

 

How do you diagnose neuropathy?

It is mostly a diagnosis of exclusion.

So you test for everything else it could be.

If you cannot find another cause, it is most likely laryngeal sensory neuropathy.

In such situations, I do obtain a confirmatory test called SELSAP (surface evoked laryngeal sensory action potential) that is helpful in diagnosis as well.

 

What diseases do you test for?

Postnasal drip from allergies, food sensitivities, autoimmune disorders, pulmonary issues such as asthma, reactive airway disease, lung cancer, neck masses, esophageal problems like Zenker’s diverticulum, esophageal dysmotility, esophageal stenosis, achalasia, and reflux.

Once those have all been completely evaluated and ruled out, then I consider neuropathy.

 

Is there anything that can test specifically for laryngeal sensory neuropathy?

Typically, I do a SELSAP test. That is short for “surface-evoked laryngeal sensory action potential”. It tests the function of the superior laryngeal nerve with electrodes.

Surface-evoked laryngeal sensory action potential

It’s the only test that I’m aware of that measures this nerve’s functionality. It is not a foolproof test, but it’s the only one we have.

 

Why don’t you do this test immediately instead of testing for all those other things?

Just because the test is positive, does not mean that neuropathy is the immediate or only cause of the symptoms.

You could have another disease that is causing the neuropathy. If you heal that disease, your neuropathy might go away as well.

For example, reflux can cause neuropathy. The reflux is causing the nerves to not function properly.

That’s why you have to evaluate and completely treat issues like reflux before you do a test like SELSAP; because if you have active reflux, the SELSAP results may not be entirely accurate.

 

How is reflux causing the neuropathy?

Just from chronic irritation.

The laryngeal nerves are very close to the surface in the larynx. That is why they can get irritated very easily by inflammation.

 

When you have neuropathy from reflux and you fix the reflux, does the neuropathy go away completely? Or can there be permanent damage?

It’s unknown.

You have to keep in mind that this form of neuropathy is something that the medical community just became aware of in recent years.

That said, with treatment, the neuropathy symptoms may resolve slowly to point that medications may no longer be needed.

 

And on top of that, LPR is not that well researched either. I can imagine that there is not much known about the interaction of neuropathy and LPR.

Correct.

 

Let’s talk about the treatment of laryngeal sensory neuropathy.

Someone who has had neuropathy for years will likely need medication for 1 or 2 years. After that, I taper down the dose.

The neuropathy may be permanent or it may not. I treat it with the intention that the person may not need to be on these medications for the rest of their life. However, they may need to be on it for years initially.

 

This was something that was confusing to me when I researched the topic. Some literature states that if you have neuropathy for a while, it becomes permanent. Other literature says that you can basically “reset” your nerves with medication – even if you’ve had the neuropathy for a long time.

It’s unknown.

We’ve only known about this condition for around five to seven years, so we don’t have people who’ve been on medication for 20 years. Therefore, we do not know what happens in the long term.

That’s why I can’t clearly answer your question, but I have had patients with neuropathy who I treat with medications for a year or two and when I wean them off the meds, their cough does not come back.

 

What medications do you use?

Gabapentin and Amitriptyline are my top two, and then more rarely I will go with Nortriptyline or Pregabalin.

 

What dosage do you use?

There is no standard dosing.

Typically, I start the person on a low dose.

With the Gabapentin, I start them at 100 mg three times a day, and then, depending on side effects and response, I’ll go as high as 600 mg three times a day.

 

If I understand correctly, 100 mg is a very low dosage.

Correct, but people respond at that dosing so I don’t need to go higher if they respond.

 

Do people usually have side effects at 100 mg?

Some people have side effects even at that low of a dose. Other people don’t have side effects until they get a higher dosage.

Everyone is different.

 

Do you use different types of medication for different symptoms?

No.

 

Does the medication for neuropathy work against pain in general or only specifically when you have pain from nerve damage?

It’s just pain from the nerve damage.

It calms the nerve down, so it doesn’t send a faulty signal anymore. Otherwise, the nerve would send signals, for example for pain.

Or in the case of sensory neuropathic cough: the nerve stops sending the tickle that makes the person want to cough.

 

Could it mask other real pain that you have?

If you break your leg, the neuropathy medicine is not going help with the pain.

It’s not a painkiller. It works only for those incorrect signals that a damaged nerve sends.

 

In your article, you wrote that you should put people with suspected reflux first on maximum anti-reflux medication before you do medication for neuropathy.

If the person potentially has reflux then I aggressively treat the reflux. I also evaluate with a variety of tests to fully evaluate reflux: barium swallow, 24-hour multichannel pH and impedance testing, manometry, esophagoscopy.

 

Can you start treating neuropathy before the reflux is fixed?

You need to control or rule out reflux before you consider neuropathy.

Imagine someone gets inflamed tonsils all the time, and he has a sore throat from that. You would not give them medication for neuropathy to treat that sore throat. You treat the root cause, for example by removing the tonsils first.

Reflux is no different.

If reflux medication, dietary, and lifestyle measures don’t work, then surgical intervention may need to be considered. Otherwise, the reflux will continue irritating the nerves and sensory neuropathy will just continue to get worse.

 

I know that some of my readers get treated like this: They have active reflux, but get told they are just hypersensitive. Then they are put on neuropathy medication to treat that.

I’ll tell you what will happen.

Let’s say a person has reflux, you’ve done maximal reflux medications, and you say, okay, you probably have some neuropathy, let’s put you on some neuropathy medications.

What is probably going to happen is if they have neuropathy along with reflux their symptoms will actually get better.

At least for the moment.

But after a while, the neuropathy medication doesn’t work anymore; because the reflux is still irritating the nerve, which is the reason for the neuropathy.

If you don’t treat the triggering problem and you just treat the neuropathy, eventually the neuropathy medicine is not going to work because the reflux is still happening and continuing to irritate the nerve.

So the neuropathy keeps getting worse until the medication does not work anymore. And then patients are back to where they started.

 

Is there anything else that is important to know about neuropathy or reflux?                                                                                            

I would stress that symptoms do not always stem from what it looks like at first.

For example, a lot of my patients get diagnosed with reflux before they see me. But when I check them, I find out that some of them do not have reflux. Instead, their symptoms stem from allergies, food sensitivities or other diseases.

With neuropathy, it’s the same. People say, oh, I have neuropathy, even though they haven’t been tested or treated for these other issues that can lead to similar symptoms.

It’s like a fever: which could be due to sepsis, an upper respiratory infection, a kidney infection, bronchitis, an ear infection, a sinus infection and many other things.

I think keeping this in mind is important. Just because you have the typical signs does not mean you definitely have reflux or neuropathy.

You may.

But there are many other things that can cause the same symptoms. You can’t get tunnel visioned and assume that it’s got to be this one thing.

OR, in the case of reflux it is really often the cause of chronic throat symptoms. But it is not the only cause.

That is why you have to get thoroughly tested.

 

Alright, thank you very much for all the helpful information!

End of the interview

 

I mentioned that I found Dr. Chang because of the article he wrote on chronic cough. If you want to read it: you can find it at this link.

If your symptoms are more located in the mouth, you might have burning mouth syndrome. You can read more about that here.

In the interview, we mentioned reflux frequently in connection with and as a cause of neuropathy. Did you search on Google for neuropathy or chronic cough but you have never heard of the type of reflux that reaches the airways – called LPR?

LPR is short for laryngopharyngeal reflux. Basically, stomach content that reaches your airway and causes damage there. Another term for it is silent reflux. Click here to find more information on LPR.

test for silent reflux