From the Guidelines
A squeaky breath sound at the end of inhalation is called inspiratory stridor, which is typically caused by conditions such as vocal cord dysfunction (VCD), exercise-induced laryngeal prolapse, or laryngomalacia, as noted in the study published in the Journal of Allergy and Clinical Immunology 1. This high-pitched sound occurs when air flows through a constricted airway passage, most commonly in the larynx (voice box). Inspiratory stridor can result from various conditions, including paradoxical vocal cord dysfunction, exercise-induced laryngeal abnormalities, and other glottic disorders. Some key characteristics of inspiratory stridor include:
- It is a differentiating hallmark sign of exercise-induced laryngeal dysfunction (EILD) and not of exercise-induced bronchoconstriction (EIB) 1
- The presence of inspiratory symptoms does not necessarily differentiate athletes with and without EILD 1
- Flattening of the inspiratory curve on spirometric maneuvers can be seen concomitant with symptoms 1
- EILD can occur alone or with EIB, and failure to respond to asthma management is a key historical feature suggesting EILD that mimicked attacks of asthma 1 Inspiratory stridor is considered a significant finding that requires further evaluation to determine the underlying cause, which may include laryngoscopy, spirometry, or other diagnostic tests. Treatment depends on identifying and addressing the underlying cause, which may include medications or other interventions to manage symptoms and prevent complications.
From the Research
Definition and Causes of Squeaky Breath Sound
- A squeaky breath sound at the end of inhalation is commonly referred to as stridor 2, 3.
- Stridor is a variably pitched respiratory sound caused by abnormal air passage during breathing, often resulting from upper airway obstruction 3.
- It can be heard on inspiration, typically due to supraglottic or glottic obstruction, or on expiration, originating from obstruction at or below the glottic level and/or severe upper airway obstruction 3.
Possible Causes of Stridor
- Stridor can be caused by various congenital and acquired disorders, including airway edema, smooth muscle constriction, increased secretions, vascular congestion, mass lesions, scarring, or foreign bodies 4, 2.
- It may be acute, caused by inflammation or infection, or chronic, and can be congenital or acquired 2.
- The underlying cause of stridor must be sought, as it is not a diagnosis in itself, but rather a sign of an underlying condition 2.
Relationship to Wheezing
- Wheezing is a different type of respiratory sound, defined as high-pitched, continuous, adventitious lung sounds produced by oscillation of opposing airway walls whose lumen is narrowed 4, 5.
- While wheezing is often associated with obstructive airway diseases, such as asthma, stridor is more commonly related to upper airway obstruction 4, 3.
- Both stridor and wheezing can be heard in patients with airway obstruction, but they have distinct characteristics and causes 4, 3, 5.