Benign Stridor Often Mistaken for Laryngospasm

Laryngospasm causes a high-pitched squeak or wheezing sound when a person is trying to breath due to abnormal vocal cord movement. Watch video regarding this condition.

Larygnospasm (the most severe form of vocal cord dysfunction) is commonly misdiagnosed as asthma and patients may go for years labelled as asthmatic even though they may not have it at all.

However, though laryngospasm is often the victim of misdiagnosis, there is a condition known as non-organic stridor which is often misdiagnosed as laryngospasm (culprit as well as victim of misdiagnosis).

Here is a video example (watch the movie clip all the way to the end) of a patient with non-organic stridor who was initially misdiagnosed with asthma, than misdiagnosed as having vocal cord dysfunction/laryngospasm before being finally correctly diagnosed with having non-organic stridor.

As you can see, the vocal cords remain apart which immediately rules out the diagnosis of laryngospasm.

What is also apparent is the wheeze or stridor noise is due to vocal cord vibration while they are apart.

The fast moving inhalation/exhalation literally rattles the vocal cord membranes just like a strong wind flaps around an American flag resulting in "noise". No need for the vocal cords to come together to create the noise. The fast moving air does it all by itself.

The existence of non-organic stridor is one of the main reasons why laryngoscopy during a "breathing attack" suspected to be due laryngospasm is so important.

It's also why I have my patients run around my office until they become symptomatic before I perform this exam. Why do an exam when breathing is completely normal???

What is the treatment? Just reassurance... Given it is the fast-moving air that is causing the noise, one simply has to slow the breathing down. No inhalers, no epinephrine, no medications are needed.

For whatever reason, by far the most common patient who suffers from non-organic stridor is a female high school athlete.

Laryngospasm in a Child

Washington Post published a story July 23, 2012 regarding a child who suffered from laryngospasm attack that was erroneously diagnosed as asthma.

Laryngospasm is when the true vocal cords (TVC) come together rather than apart when breathing. Normally, only when talking do the vocal cords come together (or adduct) and vibrate to create a voice. When breathing, the vocal cords separate (or abduct) to allow air to pass between the vocal cords and into the lungs. Watch video.

What the story portrayed is not uncommon and patients who suffer from laryngospasm may go for years without the correct diagnosis.

The voice therapy that was recommended is also appropriate to help him cope when an attack occurs.

However, that's also the point where I start to disagree with the article.

It is all fine and dandy to learn breathing coping strategies, but that only deals with WHEN an attack occurs. What about what causes an attack to happen in the first place? Would it not be better to prevent an attack from happening at all and thereby coping strategies don't even need to be initiated?

As such, I do feel it important to start an aggressive workup to evaluate all the known triggers that may initiate a laryngospasm attack. Such triggers include allergy, post-nasal drainage, and reflux.

As long as the trigger is not addressed, a patient can continue to suffer recurrent attacks.

Once the triggers are found and fixed... the laryngospasm attacks can be "cured."

Watch the video below depicting larygnospasm as well as less severe forms of the same (vocal cord dysfunction or paradoxical vocal cords).

Source:
Long-ago asthma diagnosis didn’t explain boy’s difficulty breathing. Washington Post 7/23/12

Hiccups and Laryngospasm

So one day I was having some bad hiccups... you know, the obnoxious kind complete with strangled noise and chest jerks.

However, this experience unlike the numerous prior episodes of hiccups triggered an intellectual brainstorm about breathing and stridor in general.

FACT:
Hiccups (aka singultus) are due to brief, intermittent, and involuntary diaphragm contractions against a closed glottis. For the layperson, this means during a hiccup:

• Your body takes a quick breath inwards (inhalation)
• Your body brings the vocal cords together
• Both above actions occur simultaneously, involuntarily, and briefly 

Which brought me to consider another disorder called laryngospasm which is the most severe form of vocal cord dysfunction. In this particular condition, the vocal cords come together involuntarily just as in hiccups... BUT, it may last for seconds to minutes while the breathing is still voluntary. At worst, it results in complete airway obstruction causing a loud high-pitched squeal called stridor (check out this movie below). Click here for more information about this condition.



FACT:
Laryngospasm is due to sustained and involuntary vocal cord closure WHILE the person voluntarily tries to breath. For the layperson, this means during a laryngospasm attack:

• Your body tries to breath voluntarily
• Your vocal cords involuntarily closes for a sustained period of time
• The above actions occur simultaneously

So... when you get down to it, the only difference between hiccups which is common and afflicts many people and laryngospasm which is rare is: 1) how long it lasts for and 2) whether the diaphragmatic movement is voluntary or involuntary.

Which got me thinking... is there actually a medical condition that is BOTH a hiccup and laryngospasm at the same time?

In fact, there is... though I must preface by saying there has been only one case report (that I'm aware of) of this super-rare condition called "Diaphragmatic Flutter with Stridor."

Reported back in 1995, the journal Chest reported a 13 years old girl who presented with rapid stridulous panting that occurred only during inspiration while awake (symptoms disappeared while asleep). Laryngoscopy showed an abnormal closed glottis. ECG noted noncardiac electrical activity due to involuntary diaphragmatic contractions occurring at a rate of 200/min. Fluoroscopy of her diaphragm revealed rapid myoclonic contractions of the left hemidiaphragm.

In essence, she was "hiccuping" 200 times per minute while having a sustained laryngospasm attack. The suffering this child and her family must have gone through must have been unbelievable and I'm sure tracheostomy must have been entertained at some point.

Treatment (cure) ultimately was achieved by crushing the patient's left phrenic nerve.

So let's take a look at all three conditions in table format:

	Diaphragm Contraction	Vocal Cord Closure	Timing
Hiccups	Involuntary	Involuntary	Brief
Laryngospasm	Voluntary	Involuntary	Sustained
Diaphragmatic Flutter	Both	Involuntary	Sustained

The common theme between all three disorders is the involuntary vocal cord closure resulting in airway obstruction. The variation in presentation is utterly dependent on whether the diaphragm contraction is involuntary or not and how long the "attack" lasts for.

References:
Diaphragmatic Flutter Presenting as Inspiratory Stridor. 10.1378/chest.107.3.872 CHEST March 1995 vol. 107 no. 3

Laryngospasm and Other Forms of Vocal Cord Dysfunction. Fauquier ENT.