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.

Treatment for Hiccups Based on Science

So... I came across a few references addressing treatment of hiccups (otherwise known as singultus) based on science rather than heresay. Here are a few methods than can be done at home without the need for medications or procedures.

It is felt that hiccups may be secondary to irritation of the phrenic nerve (which innervates the diaphragm). As such, scientific treatment of hiccups have relied on increasing PaCO2 (breath holding, breathing into a paper bag), therapy using diaphragm relaxation (baclofen or phrenic nerve block), or positive airway pressure.

So, one paper described a technique called supra-supramaximal inspiration that would increase PaCO2, diaphragmatic immobilization, and positive airway pressure. The technique is as follows:

Patients are instructed to inspire maximally, hold the breath for 10 seconds, then add an additional, small, “supra-maximal” inspiration, without any expiration. The breath is held for 5 seconds, followed by a third, “supra-supramaximal” inspiration, held for 5 seconds, before resuming normal breathing.

A variant on this technique requires an assistant. The assistant first applies firm pressure just anterior to the tragus of the ear, firm enough to completely occlude the ear canal. The patient than drinks a glass of water for about 10 seconds. If no liquid is available, the Valsalva manoeuvre would suffice.

In another method, pressure is applied to the sphenopalatine ganglion. This method involves sliding a finger (or thumb) to the junction between the hard and soft palate in the mouth. In this region, firm pressure is appled for 5-10 seconds towards the back-top part of the head. Enough pressure needs to be applied to cause some pain. One can massage this junction as well. I believe this method was reported in the New England Journal of Medicine, but for the life of me, I can't find the reference.

Digital rectal massage has been reported in the literature to help stop hiccups, mainly by disrupting the vagal afferent limb of the hiccup reflex arc. Name says it all. Essentially, you stick a finger up the anus and massage the area firmly until hiccups stop.

Direct vagal stimulation, such as by carotid massage, Valsalva maneuver, and ocular pressure have also been reported.

Reference:
Miracle hiccough cure gets the attention it deserves. BMJ. 2006 December 9; 333(7580): 1222.
doi: 10.1136/bmj.39051.721632.3A.

Bloodletting and miraculous cures. BMJ 2006;333:1127-a (25 November.)

Termination of idiopathic persistent singultus (hiccup) with Supra-Supramaximal Inspiration. J Emerg Med. 2004 Nov;27(4):416-7.

Termination of intractable hiccups with digital rectal massage. J Intern Med. 1990 Feb;227(2):145-6.