Stridor in newborns is caused by airway obstruction due to congenital anomalies, infections, or inflammation affecting the larynx or trachea.
Understanding the Nature of Stridor in Newborns
Stridor is a harsh, high-pitched sound heard during breathing, typically when air flows through a narrowed or obstructed airway. In newborns, this sound signals a potential problem with the upper airway, often involving the larynx (voice box) or trachea (windpipe). The delicate anatomy of infants makes them particularly vulnerable to airway obstructions that can cause stridor. Recognizing the causes behind this symptom is crucial for timely diagnosis and effective management.
Newborns have smaller and softer airways compared to older children and adults. Even minor swelling or structural abnormalities can lead to significant airflow disruption. The causes of stridor in newborns range from congenital malformations present at birth to infections acquired shortly after delivery. Identifying the root cause allows healthcare providers to tailor interventions appropriately, preventing complications such as respiratory distress or failure.
Common Congenital Causes of Stridor in Newborns
Congenital anomalies are among the most frequent culprits behind stridor in newborns. These structural issues develop during fetal growth and may be diagnosed immediately after birth or during early infancy when symptoms become apparent.
Laryngomalacia: The Leading Cause
Laryngomalacia accounts for nearly 60-75% of all cases of stridor in neonates. It results from the softening of the laryngeal tissues above the vocal cords. This softness causes the tissues to collapse inward during inhalation, partially blocking airflow and producing a characteristic noisy breathing sound.
Typically, laryngomalacia presents within the first few weeks of life, peaking around 6 months before resolving spontaneously by 12-18 months in most cases. Though mostly benign, severe cases can lead to feeding difficulties, failure to thrive, or apnea episodes requiring medical intervention.
Vocal Cord Paralysis
Unilateral or bilateral vocal cord paralysis can cause stridor by impairing normal vocal cord movement and narrowing the airway. This condition may arise from birth trauma, neurological disorders, or unknown causes (idiopathic). Bilateral paralysis often results in more severe respiratory compromise compared to unilateral.
Newborns with vocal cord paralysis might exhibit weak cry, choking during feeding, or cyanosis in addition to stridor. Diagnosis typically involves direct visualization using flexible laryngoscopy.
Subglottic Stenosis
Subglottic stenosis refers to narrowing below the vocal cords at the subglottic space. It can be congenital due to incomplete development of airway structures or acquired from prolonged intubation injury. In newborns presenting with stridor without a clear cause like laryngomalacia, subglottic stenosis should be considered.
The severity varies widely; mild stenosis may only cause noisy breathing while severe cases can obstruct airflow significantly requiring surgical correction.
Other Congenital Anomalies
Less common congenital causes include:
- Tracheomalacia: Weakness and floppiness of tracheal cartilage causing airway collapse.
- Laryngeal webs: Thin membranes across part of the larynx obstructing airflow.
- Vascular rings: Abnormal blood vessels encircling and compressing the trachea.
- Choanal atresia: Blockage of nasal passages potentially leading to noisy breathing.
Each anomaly has distinct clinical signs but shares stridor as a common symptom due to compromised airway patency.
Infectious and Inflammatory Causes Leading to Stridor
While congenital issues dominate neonatal stridor cases, infections and inflammation can also provoke upper airway obstruction.
Laryngitis and Croup
Though more common in toddlers than newborns, viral infections like croup occasionally affect infants causing inflammation and swelling around the larynx. This swelling narrows airways resulting in stridor accompanied by barking cough and hoarseness.
Newborn immune systems are immature making them vulnerable but also less likely to manifest classic croup symptoms immediately. Prompt treatment with steroids or nebulized epinephrine often relieves symptoms rapidly.
Bacterial Infections: Epiglottitis and Bacterial Tracheitis
Serious bacterial infections such as epiglottitis (inflammation of epiglottis) or bacterial tracheitis can cause rapid-onset severe stridor with respiratory distress. These conditions are medical emergencies requiring immediate antibiotic therapy and often airway support like intubation.
Vaccination programs have reduced incidence drastically but vigilance remains critical especially for unvaccinated infants or those exposed to pathogens like Haemophilus influenzae type b (Hib).
Gastroesophageal Reflux Disease (GERD)
GERD can indirectly contribute to stridor by causing chronic irritation and inflammation of upper airway tissues due to acid reflux reaching the larynx (laryngopharyngeal reflux). This irritation leads to swelling that narrows airways intermittently.
Newborns with GERD-related stridor may show feeding difficulties alongside typical reflux symptoms such as spitting up or irritability after feeds.
Other Factors Contributing to Stridor Development
Several additional factors may exacerbate or trigger stridor episodes in newborns beyond primary anatomical abnormalities or infections.
Birth Trauma
Difficult deliveries involving forceps use or prolonged labor can injure delicate structures in a newborn’s neck causing swelling, hematomas, or nerve damage affecting vocal cord function leading to transient or persistent stridor.
Prematurity and Low Birth Weight
Premature infants often have underdeveloped lung and airway structures making them prone to conditions like tracheomalacia that produce noisy breathing sounds including stridor.
Low birth weight babies tend also have weaker immune defenses increasing susceptibility to infectious causes mentioned earlier.
Allergic Reactions and Foreign Body Aspiration
Though rare in newborns due to limited exposure risks, allergic reactions causing upper airway swelling (angioedema) might trigger sudden onset stridor. Similarly, accidental aspiration of small objects into airways can cause obstruction manifesting as acute stridor requiring emergency care.
The Diagnostic Approach for Newborn Stridor
Pinpointing what causes stridor in newborns involves a thorough clinical evaluation paired with targeted diagnostic tools aimed at visualizing airway anatomy and function.
Clinical History & Physical Examination
A detailed history includes onset timing (immediate vs delayed), associated symptoms like feeding problems or cyanosis, prenatal history for anomalies, birth details including trauma events, infection exposure risk factors, and family history of congenital conditions.
Physical examination focuses on identifying audible sounds’ timing (inspiratory vs expiratory), severity signs such as retractions or oxygen desaturation alongside general health assessment.
Imaging Studies
Imaging plays a pivotal role:
- X-rays: Neck soft tissue films help detect subglottic narrowing or foreign bodies.
- MRI/CT scans: Detailed views for vascular rings or complex malformations.
- Barium swallow studies: Assess swallowing function if aspiration suspected.
Laryngoscopy & Bronchoscopy
Direct visualization using flexible fiberoptic laryngoscopy is often performed bedside allowing real-time assessment of dynamic airway collapse such as seen in laryngomalacia. Bronchoscopy extends examination into lower trachea and bronchi if needed for comprehensive evaluation especially before surgical planning.
| Cause Category | Description | Treatment Options |
|---|---|---|
| Laryngomalacia | Soft supraglottic tissue collapses inward on inspiration causing partial obstruction. | Usually self-resolves; severe cases need surgery (supraglottoplasty). |
| Vocal Cord Paralysis | Impaired vocal cord mobility reducing airway space; unilateral/bilateral involvement. | Avoid irritants; voice therapy; surgery if respiratory distress present. |
| Bacterial Tracheitis/Epiglottitis | Bacterial infection causing acute severe inflammation/swelling obstructing airway. | Epinephrine nebulizers; antibiotics; possible intubation/emergency airway management. |
| Subglottic Stenosis | Narrowing below vocal cords either congenital or post-intubation injury. | Mild cases monitored; severe require dilation/surgical reconstruction. |
| Laryngeal Web/Tracheomalacia/Vascular Rings | Anatomic abnormalities causing partial extrinsic/intrinsic obstruction. | Surgical repair depending on severity/location. |
| GERD-related Inflammation | Laryngeal irritation secondary to acid reflux provoking edema/narrowing. | Avoid triggers; acid suppression therapy; feeding modifications. |
| Laryngitis/Croup | Viral inflammation causing supraglottic swelling producing characteristic cough/stridor. | Steroids; nebulized epinephrine; supportive care. |
| BIRTH TRAUMA | Soft tissue injury/nerve damage impacting vocal cord function resulting in noisy breathing. | Supportive care; monitor recovery; surgical intervention rare. |
Key Takeaways: What Causes Stridor In Newborns?
➤
➤ Congenital airway abnormalities often cause stridor.
➤ Laryngomalacia is the most common cause in newborns.
➤ Infections can lead to inflammation and airway narrowing.
➤ Vocal cord paralysis may result in noisy breathing.
➤ Foreign bodies or swelling can obstruct the airway.
Frequently Asked Questions
What Causes Stridor in Newborns?
Stridor in newborns is primarily caused by airway obstruction due to congenital anomalies, infections, or inflammation affecting the larynx or trachea. The delicate and small airways of infants make them vulnerable to such obstructions, leading to the characteristic noisy breathing.
How Does Laryngomalacia Cause Stridor in Newborns?
Laryngomalacia is the leading cause of stridor in newborns. It occurs when the soft tissues above the vocal cords collapse inward during inhalation, partially blocking airflow. This condition usually appears within weeks after birth and often resolves by 12-18 months without intervention.
Can Vocal Cord Paralysis Cause Stridor in Newborns?
Yes, unilateral or bilateral vocal cord paralysis can cause stridor by limiting vocal cord movement and narrowing the airway. This condition may result from birth trauma or neurological issues and can lead to feeding difficulties and respiratory distress in affected newborns.
Are Infections a Common Cause of Stridor in Newborns?
Infections can cause inflammation of the upper airway structures like the larynx or trachea, leading to stridor in newborns. Prompt diagnosis and treatment are essential to reduce airway swelling and prevent complications such as respiratory distress.
Why Is Early Recognition of Stridor Causes Important in Newborns?
Early recognition of what causes stridor in newborns is crucial for timely diagnosis and management. Identifying the root cause helps healthcare providers tailor treatments effectively, preventing severe complications like respiratory failure or feeding problems.
Treatment Strategies Based on Underlying Causes
Treatment hinges entirely on identifying what causes stridor in newborns since management varies widely from observation alone up to emergency surgical interventions.