A young man came to see me the other day complaining of several episodes of frightening shortness of breath. The first episode developed quickly one day when he was leaving work. He had been tired that week, perhaps with early symptoms of a respiratory tract infection or perhaps his allergies were acting up, but his distress seemed to come on “out of the blue.” Quite abruptly, he recalled, he couldn’t breathe. His symptoms improved relatively quickly, such that by the time he arrived home 30 minutes later he felt all better, although frightened by such a severe attack.
He experienced several similar events over the next few weeks, many waking him from his sleep. He had no prior history of asthma, although he had a history of mild seasonal rhinitis. He experienced occasional post-nasal drip and had no symptoms of heartburn to suggest gastroesophageal reflux. He had never been told of asthma as a child, and he was a lifelong non-smoker.
When questioned more about his difficulty breathing, he was quite clear: he simply could not get air in or out of his chest. It was not that it was hard to empty the air from his chest, he said, it was that no air would move at all. He was given an albuterol inhaler to try, but found it difficult to use and in truth had not tried it.
He reported only minimal cough, no sputum production. He had not experienced wheezing, but recalled a respiratory sound that he made as his episodes gradually resolved. His wife thought that she too had heard a breathing noise, particularly when he tried to breathe in. They have two cats at home but noted no increased likelihood of symptoms when around the cats. In the absence of these attacks, he felt well and was able to work out at the gym without limitation due to his breathing. His only medications were vitamin D and glucosamine chondroitin.
His chest examination was normal. Chest X-ray was normal. Breathing tests (spirometry) performed at a time when he felt well was likewise normal. And the question was: is this asthma?
Asthma causes symptoms that come and go. Between attacks one can feel entirely well with a normal chest exam and normal lung function. However, the history that this young man offered was atypical in several ways, including no prior history of asthma; sudden severe attacks that came on without warning and resolved within a few minutes without treatment; and his sense that during these spells it was not hard to breathe, but impossible to breathe at all – no air movement in or out at all. As the episode abated, there came an inspiratory sound; and when asked if he could localize the site of his distress, he offered that he thought his problem was in his throat more than in his chest.
The diagnosis? Not asthma but laryngospasm – an alternative and more plausible explanation for these sudden attacks of difficulty breathing. Imagine that some irritant triggers the vocal cords to suddenly come together and tightly obstruct the upper airway. One cannot breathe (or talk), and it feels as though one were about to suffocate to death. One tries to inhale or exhale, but no air can pass the closed glottis. After what seems like an eternity but is probably well less than one minute, the laryngeal spasm begins to abate. As the vocal cords begin slowly to move apart, one can start to get air passed, with an inspiratory sound that we recognize as stridor. At first air enters the lungs with increased resistance through the narrowed upper airway, but over several seconds, as the laryngeal muscles further relax and the vocal cords abduct fully, normal breathing is restored. The entire event is over in a minute or two, and no medication is needed (or likely to help). An inhaled bronchodilator might be more irritating to the larynx and should probably be avoided.
What causes some people to develop laryngospasm is not known. Our young man had a normal ENT examination with direct laryngoscopy to exclude a structural abnormality of the glottis. His laryngeal sensitivity developed without prior trauma or other explanation. Potential triggers that may set off spasm of the sensitized larynx include mucus draining from the posterior pharynx, acid refluxed from below, cough with secretions expectorated at high velocity, or oro-pharyngeal aspiration.
Preventing provokers of laryngospasm, such as laryngopharyngeal reflux, is an important treatment, especially in persons with frequent night-time episodes. Other management strategies that have been described include “rescue breathing” techniques taught by speech-language therapists; application of forward and upward pressure behind the earlobes and in front of the mastoid processes in what has been described as the “laryngospasm notch”; and, rarely, botox injections into the larynx.
In most instances, coming to understand the mechanism of the event is key to dealing with it: one needs to try to stay calm, attempt small breaths in through the nose, and perhaps visualize relaxation and separation of the vocal cords. Knowing that the spasm of the larynx will pass in a matter of seconds and that there will be no long-term harmful effect are the reassurances that we have to offer. Distinguishing these episodes from asthma attacks is also crucially important. Treatment with bronchodilators and corticosteroids will not bring relief or prevent episodes of laryngospasm. It only confuses the issue, obscures the diagnosis, and likely frustrates the sufferer.