Stridor is a high-pitched breathing sound in babies, indicating partial upper airway obstruction. This distinctive sound signals that air movement through the voice box, windpipe, or surrounding structures is turbulent due to a narrowing. Understanding stridor is important for parents because it can range from a harmless, temporary condition to a sign of a more serious problem requiring prompt medical attention.
Understanding the Sound of Stridor
Stridor is characterized by a high-pitched, often harsh, or squeaky sound, which some describe as a crowing noise or similar to a seal’s bark. This sound typically occurs during inhalation, known as inspiratory stridor, indicating a narrowing in the upper airway, particularly around the voice box. In some instances, the sound may also be heard during exhalation (expiratory stridor) or throughout both phases of breathing (biphasic stridor), which can point to different locations of airway narrowing.
Stridor differs from other common noisy breathing sounds in infants. Wheezing is a lower-pitched, whistling sound from smaller airways, often heard during exhalation. Stertor is a low-pitched, snoring-like noise from nasal or throat congestion. Recognizing the specific quality and timing of the sound helps identify the source of the noisy breathing.
Common Causes of Stridor in Babies
Several factors can lead to stridor in babies, often due to their smaller, softer airways being prone to obstruction. One of the most frequent causes, especially in newborns and infants, is a condition called laryngomalacia. This occurs when the cartilage and tissues above the vocal cords are softer than they should be, causing them to temporarily collapse into the airway during inhalation. Laryngomalacia typically presents within the first few weeks of life and often improves as the baby grows and their tissues stiffen, usually resolving by 18 to 24 months of age.
Infections are another common cause of stridor, with croup being a prominent example. Croup is a viral infection causing swelling in the voice box and windpipe, resulting in a barking cough and stridor. While less common now due to widespread vaccination, epiglottitis, a severe bacterial infection causing swelling of the epiglottis, also presents with stridor and requires immediate medical attention.
Foreign body aspiration, where a small object or piece of food gets lodged in the airway, is a sudden and serious cause of stridor, particularly in older infants and toddlers. This can cause an abrupt onset of choking, coughing, and noisy breathing. Less common causes of stridor include congenital conditions like subglottic stenosis, which is a narrowing of the airway below the vocal cords, or vocal cord paralysis, where the vocal cords do not move properly. These conditions may be present from birth and can also contribute to noisy breathing.
When to Seek Medical Care
Parents should know when stridor requires medical evaluation. While some cases of stridor are benign and self-resolving, certain signs indicate that a baby is experiencing significant respiratory distress and requires prompt medical attention. One such sign is increased effort in breathing, which may manifest as retractions, where the skin pulls in around the ribs or neck with each breath. Nasal flaring, where the nostrils widen with each breath, and unusually rapid breathing are also indicators of breathing difficulty.
A bluish discoloration around the mouth, lips, or fingernails (cyanosis) signals a severe lack of oxygen and is an urgent medical emergency. Changes in a baby’s behavior, such as unusual lethargy, extreme drowsiness, or unresponsiveness, can also be serious warning signs. If a baby with stridor has difficulty feeding, chokes frequently, or struggles to swallow, it could indicate an airway issue impacting their ability to eat. A high fever accompanying stridor, or if the stridor suddenly worsens or has a rapid onset without a clear explanation, warrants immediate medical consultation.
Diagnosing and Managing Stridor
When a baby presents with stridor, healthcare providers begin with a physical examination and medical history. The doctor listens carefully to the stridor, noting its characteristics, such as when it occurs during the breathing cycle, and assess for any signs of respiratory distress. This initial assessment helps in localizing the potential area of airway obstruction and determining the urgency of the situation.
Depending on the suspected cause and severity, further diagnostic tests may be recommended. Imaging studies like X-rays of the chest and neck can help identify infections, foreign bodies, or structural abnormalities. In some cases, a procedure called flexible laryngoscopy may be performed, which involves inserting a thin, flexible tube with a camera through the nose to visualize the voice box and upper airway. For a more detailed view of the lower airway, a bronchoscopy might be necessary.
Stridor management depends on the underlying cause. For mild cases of laryngomalacia, observation is often sufficient, as the condition frequently resolves on its own as the child grows. If an infection like croup is the cause, medications such as corticosteroids may be prescribed to reduce swelling in the airway. Severe cases, or those caused by foreign body aspiration, may require hospitalization, and in rare instances, surgical intervention might be needed to correct a structural issue or remove an obstruction.