An unusual breathing sound can be concerning. Stridor is one such sound, indicating a specific type of airway issue. Recognizing it and its potential causes helps understand when it signals a serious health matter.
What Stridor Sounds Like
Stridor is a high-pitched, often harsh or musical sound, frequently audible without a stethoscope. It is typically most prominent during inhalation (inspiratory stridor), but can also occur during exhalation or both phases (biphasic stridor). The sound arises from turbulent airflow through a narrowed upper airway, causing vibrations that produce the audible sound.
Unlike a wheeze, which originates in the lower airways and sounds more whistling, stridor indicates an obstruction higher up in the respiratory system, specifically the extrathoracic upper airway (pharynx, larynx, or trachea). A different sound, stertor, resembles snoring and is lower-pitched, stemming from nose or throat congestion. Stridor’s unique quality, often described as crowing or grating, helps differentiate it from other breathing noises.
Why Stridor Occurs
Stridor results from any condition causing narrowing or obstruction within the upper airway. This narrowing forces air through a smaller opening, leading to the turbulent airflow that produces the characteristic sound. Various factors contribute to this constriction, including swelling of airway tissues due to infections like viral croup or epiglottitis, or from allergic reactions such as anaphylaxis.
Foreign objects lodged in the airway are another common cause, particularly in children. Structural issues, either present from birth (congenital) or developing later, can also lead to airway narrowing. Examples of congenital causes include laryngomalacia, where soft tissues of the voice box are floppy, or subglottic stenosis, a narrowing below the vocal cords. Acquired conditions like trauma, tumors, or scar tissue from previous medical procedures can also restrict the airway.
When Stridor Needs Immediate Medical Attention
Stridor is rarely a benign sign and indicates a compromised airway, warranting medical evaluation. Prompt medical attention is crucial if the stridor is sudden, worsens rapidly, or is accompanied by other signs of respiratory distress. These include increased breathing rate, visible effort (like flaring nostrils or retractions where skin pulls in between ribs, above collarbones, or below breastbone with each breath). Changes in skin color, such as a bluish tint around the lips or fingernails, indicate insufficient oxygen levels and are an emergency.
Other concerning indicators include changes in consciousness (unusual drowsiness or agitation), difficulty swallowing, or excessive drooling. Any of these symptoms with stridor signal a life-threatening situation requiring immediate medical evaluation. In such cases, seek emergency care without delay by calling emergency services or going to the nearest emergency room.