Laryngospasm

Key takeaways

Laryngospasm belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Laryngospasm to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Laryngospasm from memory before moving on to harder problems.

Reference excerpt

Laryngospasm is an uncontrolled or involuntary muscular contraction (spasm) of the vocal folds. It may be triggered when the vocal cords or the area of the trachea below the vocal folds detects the entry of water, mucus, blood, or other substance. It may be associated with stridor or retractions.

Signs and symptoms Laryngospasm is characterized by involuntary spasms of the laryngeal muscles. It is associated with difficulty or inability to breathe or speak, retractions, a feeling of suffocation, which may be followed by hypoxia-induced loss of consciousness. It may be followed by paroxysmal coughing and in partial laryngospasms, a stridor may be heard. It requires prompt identification to avoid possibly fatal complications. It may present with loss of end-tidal carbon dioxide (for mechanically ventilated patients), chest or neck retractions and paradoxical chest wall movements. The condition typically lasts less than 60 seconds, but in cases of partial blocking it may last 20 to 30 minutes and hinder inspiration, while exhalation remains easier.

Causes Laryngospasm is a primitive protective airway reflex that functions to protect against aspiration. However, it may be detrimental if there is sustained closure of the glottis resulting in blockage of respiration that hinders the free flow of air. It may be triggered when the vocal cords or the area of the trachea below the vocal folds detects the entry of water, mucus, blood, or other substance. It is most often reported 1) post-operatively after endotracheal extubation or 2) after sudden reflux of gastric contents. It is common in drowning. It is estimated that in 10% of cases of drowning as a response to inhalation of water, death occurs by asphyxia due to laryngospasm without any water in the lungs. It is also a symptom of hypoparathyroidism. It can sometimes occur during sleep, waking up the affected person. These episodic interruptions of sleep have been attributed to acute irritation due to gastro-oesophageal reflux. Laryngospasm is also an unlikely but possible side effect of ketamine administration. Laryngospasm may happen in people with neurological disease. In children, rapid detection and management are imperative to prevent deadly complications such as cardiac arrest, hypoxia and bradycardia. Patients with a history of significant aspiration, asthma, exposure to airway irritants (smoke, dust, mold, fumes, use of Desflurane), upper respiratory infections, airway anomalies, light anesthesia and patients with acute mental status depression may be at increased risk.

Prevention When gastroesophageal reflux disease (GERD) is the trigger, treatment of GERD can help manage laryngospasm. Proton pump inhibitors such as Dexlansoprazole (Dexilant), Esomeprazole (Nexium), and Lansoprazole (Prevacid) reduce the production of stomach acids, making reflux fluids less irritant. Prokinetic agents reduce the amount of acid available by stimulating movement in the digestive tract. Patients who are prone to laryngospasm during illness can take measures to prevent irritation such as antacids to avoid acid reflux. For acute context, making an upright position of the upper part of the body has been shown to shorten the spasm episodes. Fixation of the arms on stabilization of the body and slowing of breathing is also recommended.

Incidence Incidence has been estimated at approximately 1% in both adult and pediatric populations. Its incidence is reported to be more than triple in the very young (birth to 3 months of age), increasing to 10% in those with reactive airways. Other sub-populations with high incidence of laryngospams include patients undergoing tonsillectomy and adenoidectomy (25%). It is likely that more than 10% of drownings involve laryngospasm, but the evidence suggests that it is not usually effective at preventing water from entering the trachea.

Treatment Most minor laryngospasm get better on its own for most people. Laryngospasm is one of the most common intraoperative complications. It may be life-threatening as it involves reflex closure of the laryngeal muscles and thus results in inability to ventilate the patient. Treatment requires clearing secretions from the oropharynx, applying continuous positive airway pressure with 100% oxygen, followed by deepening the plane of anaesthesia with propofol, and/or paralyzing with succinylcholine.

Illustrations

Worked examples

Example 1 — a first encounter with Laryngospasm

Start with the simplest possible case. Write down what Laryngospasm claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Laryngospasm before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Laryngospasm ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Laryngospasm

In research: Laryngospasm appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Laryngospasm in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Laryngospasm is common in secondary-school and first-year university syllabi. It links to neighbouring topics Anesthesia, Larynx disorders, Otorhinolaryngology, so understanding it makes those chapters shorter.
In everyday life: Look for Laryngospasm outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Laryngospasm in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Laryngospasm means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Laryngospasm out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Laryngospasm in simple terms?

Laryngospasm is an uncontrolled or involuntary muscular contraction (spasm) of the vocal folds. It may be triggered when the vocal cords or the area of the trachea below the vocal folds detects the entry of water, mucus, blood, or other substance.

Why does Laryngospasm matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Laryngospasm?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Laryngospasm.