Laryngospasm refers to reflexive spasmodic contraction of the intrinsic muscles of the larynx, causing partial or complete closure of the glottis. This results in varying degrees of respiratory distress and, in severe cases, complete airway obstruction. It is more common in children aged 2 to 3 years but can also occur in adults.
Etiology
The exact cause remains unclear, though several factors may be involved:
Hypocalcemia is frequently observed in malnourished, weakened children or those with rickets. Triggers such as fright, intestinal parasites, constipation, or adenoid hypertrophy may also contribute.
Disorders such as obstructive sleep apnea (OSA) and laryngopharyngeal reflux can provoke episodes of laryngospasm in adults.
Stimulation during general anesthesia occurs most often during light anesthesia or in the period of incomplete anesthesia recovery. Reflexive laryngospasm is triggered by direct stimulation of the vocal cords from the endotracheal tube, secretions, or blood, especially after extubation. It is more common during upper airway surgeries in children.
Nerve damage caused by surgeries involving the thyroid, trachea, or esophagus may lead to aberrant axonal regrowth during the natural healing process. Misaligned regrowth between adductor and abductor branches or abnormal discharges could be associated with the onset of laryngospasm.
Clinical Manifestations
The condition often presents with sudden onset of inspiratory dyspnea and varying degrees of stridor. Mild cases involve slight inspiratory stridor, while severe cases may lead to complete upper airway obstruction. The former may rapidly progress to the latter. Affected individuals often appear panicked, profusely sweat, exhibit cyanosis, and experience a sensation of suffocation. However, symptoms usually resolve immediately following a deep inspiratory effort. Episodes are generally of short duration, lasting only a few seconds to a few minutes, and may occur intermittently or repeatedly.
There is typically no associated hoarseness or fever, either during or after the episode. As symptoms often subside or disappear by the time the patient seeks medical attention, laryngoscopic examination tends to reveal no significant abnormalities in vocal cord movement or glottic closure.
Diagnosis
The diagnosis is typically made based on the sudden onset and resolution of symptoms, the absence of fever and hoarseness, and the presence of inspiratory dyspnea and stridor. Laryngoscopic examination showing no abnormalities further supports the diagnosis. Nevertheless, initial episodes require differentiation from other causes of inspiratory dyspnea, such as laryngeal or tracheal foreign bodies and congenital laryngeal abnormalities.
A thorough medical history should be taken during the clinical evaluation. Cases involving foreign bodies often have a clear history of foreign body aspiration. Congenital malformations, commonly due to excessively soft laryngeal cartilage, typically manifest shortly after birth, with symptoms frequently occurring during the daytime and alleviating or disappearing during sleep. In addition to necessary laryngoscopic exams, imaging studies and laryngeal electromyography are valuable for differential diagnosis.
Treatment
There are currently no specific or highly effective treatments available. Avoidance of triggering factors and patient education on health maintenance is essential. During an episode, patients can benefit from maintaining calmness, loosening tight clothing, performing deep nasal breathing, sipping warm water slowly, or inhaling agents such as amyl nitrite. Supplemental oxygen is an option when conditions permit. In the case of pediatric patients, gently opening the mouth to facilitate deep breathing and administering oxygen may help.
Treatment may involve calcium supplementation, vitamin D, cod liver oil, and increased sun exposure. Removal of adenoids or tonsils is indicated for hypertrophy. During anesthesia extubation, careful and gentle techniques, along with timely clearing of secretions from the oropharynx and airway, are important. For severe symptoms, deepening anesthesia or, in emergencies, delivering pure oxygen through high-frequency ventilation may be necessary, along with reintubation if required.