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eMedicine Specialties > Pediatrics: General Medicine > Pulmonology

Congenital Stridor

Timothy D Murphy, MD, Assistant Professor, Department of Pediatrics, Division of Pulmonology, University of Pittsburgh; Consulting Staff, Division of Pulmonology, Children's Hospital of Pittsburgh
Clement L Ren, MD,, Chief, Division of Pediatric Pulmonology, Department of Pediatrics, Associate Professor, Golisano Children's Hospital at Strong, University of Rochester, New York

Updated: Feb 17, 2009

Introduction

Background

Stridor is a clinical sign characterized by monophonic, audible breath sounds (noisy breathing) that usually originates from the extrathoracic airways. The presence of stridor indicates a partial obstruction of the upper airways, glottis, or trachea. The pitch of the stridor is determined by the degree of airway obstruction and the velocity of the airflow; the loudness and tone of the sound also varies by the specific cause. Congenital stridor presents at birth or within the first few weeks (4-6) of life.1

Pathophysiology

Stridor results from partial obstruction of an airway with turbulent flow characteristics. Such respiratory tract areas are the upper airway, glottis, and trachea. The obstruction can be fixed or variable. Variable extrathoracic obstructions are primarily associated with inspiratory stridor. This is because, during inspiration, extrathoracic intraluminal airway pressure is negative relative to atmospheric pressure, leading to collapse of supraglottic structures. During expiration, intrathoracic pressure is positive and tends to collapse the airway. Thus, stridor caused by intrathoracic obstructions tends to be more prominent upon expiration. Stridor heard during both phases of respiration is usually due to either a fixed airway obstruction or to 2 areas of obstruction (ie, intrathoracic and extrathoracic).

Mortality/Morbidity

Congenital stridor is rarely life-threatening. Immediately life-threatening obstruction from congenital lesions such as severe micrognathia are apparent at birth, and are treated with emergent tracheotomy. Bilateral vocal cord paralysis and subglottic hemangioma may present as causes of congenital stridor that are life-threatening. Significant airway obstruction can lead to respiratory distress and failure to thrive, secondary to the increased work of breathing.

Age

Congenital stridor is present either at birth or shortly afterward.

Clinical

History

The most common presentation for congenital stridor is chronic noisy breathing since birth. Most patients come to attention by the first 4-6 weeks of life. The stridor may emerge only after a few weeks, as the baby gains strength and airflow velocity increases during that time.

The history can be helpful in determining the cause of stridor. Characteristics of stridor that should be elicited include the following:

  • Association with position
  • Association with feeding
  • Persistent versus intermittent
  • Abnormal phonation
  • Foreign body exposure
  • Presence of other congenital abnormalities

Physical

Physical examination should focus on examination of the respiratory tract, the quality and characteristics of the stridor, and other physical findings that may be associated with stridor.

  • Characteristics of the patient's stridor
    • Effect of position
    • Effect of feeding
    • Inspiratory versus expiratory
    • Pitch and loudness
  • Respiratory examination
    • Lower respiratory tract sounds (eg, wheezes, crackles)
    • Retractions
    • Quality of voice or crying
  • Other physical findings
    • Skin lesions (eg, hemangiomas)
    • Neurologic status

Causes

Differential diagnosis of stridor can be divided into supralaryngeal, laryngeal, tracheal, and nonanatomic categories.

  • Supralaryngeal causes of stridor: Supralaryngeal causes include choanal atresia, vallecular cysts, thyroglossal cysts, and tongue dermoid or teratoma.
  • Laryngeal causes of stridor
    • Laryngomalacia is the most common cause of congenital stridor. Patients typically have high-pitched inspiratory stridor that increases with crying and when supine. It rarely interferes with feeding. Symptoms are usually present at birth or within the first 4-6 weeks of life. Laryngomalacia usually resolves of its own accord within 18-24 months.
    • Vocal cord paralysis may cause a patient to have a weak cry. Patients may also be worse with feeding. Ruling out underlying conditions that may result in vocal cord paralysis, in particular neurologic conditions such as Arnold-Chiari malformation, is important. Bilateral paralysis is more commonly associated with neurologic problems and is a life-threatening emergency.
    • Subglottic stenosis can be congenital or acquired. Stridor of subglottic stenosis is typically biphasic. Acquired forms usually arise from endotracheal (ET) intubation.
    • Other laryngeal abnormalities leading to stridor include webs, cysts, hemangiomas, papillomata, and laryngotracheoesophageal clefts.
  • Tracheal causes of stridor
    • Extrinsic compression of the trachea by vascular abnormalities is a common cause of stridor. Anomalies that may lead to stridor include double aortic arch, innominate artery compression, aberrant right subclavian vein, and pulmonary artery sling.2
    • Bronchogenic cysts can also cause extrinsic compression of the trachea.
    • Tracheomalacia may be observed in association with laryngomalacia or as an isolated lesion.
    • Tracheal stenosis can be a complication of long-term ET intubation or a congenital lesion.
    • Complete tracheal rings are a subset of tracheal stenosis with severe biphasic airway sounds.
  • Nonanatomic causes of stridor
    • Cardio-vocal syndrome occurs when cardiac abnormalities lead to compression of the recurrent laryngeal nerve.
    • Foreign body may be present.
    • Gastroesophageal reflux (GER) has been associated with stridor, although no controlled studies have been performed to demonstrate that GER is actually responsible for the stridor.

Differential Diagnoses

Laryngomalacia
Vascular Ring, Double Aortic Arch
Pulmonary Artery Sling
Vascular Ring, Right Aortic Arch
Stridor
Subglottic Stenosis
Tracheomalacia

Other Problems to Be Considered

Gastroesophageal reflux (GER)
Foreign body aspiration
Laryngeal stenosis

Workup

Imaging Studies

  • Chest radiography may be helpful in diagnosing a vascular ring if a right-sided aortic arch is observed in patients with congenital stridor.
  • Standard neck radiography is rarely helpful unless a large mass is responsible for the obstruction. High-kilovoltage radiography can highlight the tracheal structures better and may provide more information. These radiographs use a higher radiation dose.
  • CT scanning of the neck and chest may be helpful, especially if the radiology facility can perform airway reconstruction imaging. However, the need for cooperation in generating such images limits the use of CT imaging in infants and young children with congenital stridor.
  • Barium esophagraphy can be helpful in diagnosing vascular rings if an indentation in the esophagus is present. The pattern of indentation may also be helpful in indicating what type of vascular anomaly may be present. However, the lesion of anomalous innominate artery does not yield abnormal findings on esophagraphy.

Other Tests

  • A multichannel sleep study that measures airflow, chest wall excursion, oxygen saturation, and heart rate can provide useful information about the severity of obstruction.
  • An ABG study can reveal the presence of carbon dioxide retention or chronic hypoxemia.
  • In cases of suspected gastroesophageal reflux (GER), 24-hour mid esophageal pH monitoring may be helpful in establishing the diagnosis.

Procedures

  • Fiberoptic laryngoscopy and bronchoscopy, valuable diagnostic tools for the evaluation of congenital stridor, offer several important advantages over radiographic imaging, including the following:
    • Lesions can be directly visualized. Evidence of inflammation or bleeding can be observed. Characteristics of the lesion, such as vascularity, can be determined.
    • Biopsies and bronchoalveolar lavage samples can be taken if necessary.
    • The examination is conducted while the patient is actively breathing, allowing assessment of dynamic events.
  • Fiberoptic direct laryngoscopy can be performed in the office. However, in the pediatric population this procedure can be performed most safely while the patient is sedated. Bronchoscopy in a child requires intravenous conscious sedation or general anesthesia.

Treatment

Medical Care

Medical care is primarily supportive because many causes of congenital stridor resolve spontaneously over time. For those that do not, such as vascular rings, surgical treatment is usually definitive. However, in some patients, tracheomalacia persists for some time after such a repair. In severe cases of congenital stridor, nonsurgical therapy may have a role prior to definitive surgical correction.

  • Supplemental oxygen can be used to treat hypoxemia.
  • Noninvasive positive pressure mechanical ventilation can maintain a patent airway in cases of airway collapse, such as tracheomalacia.
  • If an airway cannot be maintained by noninvasive positive pressure mechanical ventilation, intubation with mechanical ventilation may be indicated.

Surgical Care

Surgical management depends on the specific lesion that causes stridor.

  • In general, indications for surgical correction include the following:
    • Inability to maintain a patent airway
    • Feeding difficulties or failure to thrive
    • Inability to maintain adequate oxygenation
  • Some of the surgical procedures used to treat congenital stridor include the following:
    • Epiglottoplasty for laryngomalacia3
    • Tracheostomy for severe subglottic stenosis or tracheomalacia
    • Division of a vascular ring
    • Tracheoplasty for complete tracheal rings

Follow-up

Complications

  • The primary complication from congenital stridor is airway compromise and respiratory failure.
  • Other complications include failure to thrive secondary to increased work of breathing.

Prognosis

  • The prognosis for congenital stridor depends on the specific cause. In general, it is very good.
  • For conditions such as laryngomalacia, the condition is self-limited and resolves on its own.
  • For other conditions, such as subglottic stenosis, surgical correction is curative.

Miscellaneous

Medicolegal Pitfalls

The major medical pitfall in evaluation of congenital stridor is failure to make the diagnosis.

  • Infants are frequently diagnosed with congestion or asthma.
  • True viral upper respiratory infections in infants younger than 1 month are rare.
  • Persistently abnormal noisy breathing is unlikely to be associated with a viral illness and warrants further investigation.

References

  1. Belmont JR, Grundfast K. Congenital laryngeal stridor (laryngomalacia): etiologic factors and associated disorders. Ann Otol Rhinol Laryngol. Sep-Oct 1984;93(5 Pt 1):430-7. [Medline].

  2. Berdon WE, Baker DH. Vascular anomalies and the infant lung: rings, slings, and other things. Semin Roentgenol. Jan 1972;7(1):39-64. [Medline].

  3. Zalzal GH, Anon JB, Cotton RT. Epiglottoplasty for the treatment of laryngomalacia. Ann Otol Rhinol Laryngol. Jan-Feb 1987;96(1 Pt 1):72-6. [Medline].

  4. Cotton RT. Pediatric laryngotracheal stenosis. J Pediatr Surg. Dec 1984;19(6):699-704. [Medline].

  5. Cotton RT, Evans JN. Laryngotracheal reconstruction in children. Five-year follow-up. Ann Otol Rhinol Laryngol. Sep-Oct 1981;90(5 Pt 1):516-20. [Medline].

  6. Cotton RT, Schreiber JT. Management of laryngotracheoesophageal cleft. Ann Otol Rhinol Laryngol. Jul-Aug 1981;90(4 Pt 1):401-5. [Medline].

  7. McSwiney PF, Cavanagh NP, Languth P. Outcome in congenital stridor (laryngomalacia). Arch Dis Child. Mar 1977;52(3):215-8. [Medline].

  8. Nielson DW, Heldt GP, Tooley WH. Stridor and gastroesophageal reflux in infants. Pediatrics. Jun 1990;85(6):1034-9. [Medline].

  9. Orenstein SR, Kocoshis SA, Orenstein DM, Proujansky R. Stridor and gastroesophageal reflux: diagnostic use of intraluminal esophageal acid perfusion (Bernstein test). Pediatr Pulmonol. Nov-Dec 1987;3(6):420-4. [Medline].

  10. Parnell FW, Brandenburg JH. Vocal cord paralysis. A review of 100 cases. Laryngoscope. Jul 1970;80(7):1036-45. [Medline].

  11. Richardson MA, Cotton RT. Anatomic abnormalities of the pediatric airway. Ear Nose Throat J. Jan 1985;64(1):47-60. [Medline].

  12. Stanger P, Lucas RV Jr, Edwards JE. Anatomic factors causing respiratory distress in acyanotic congenital cardiac disease. Special reference to bronchial obstruction. Pediatrics. May 1969;43(5):760-9. [Medline].

  13. Weiss LN. The diagnosis of wheezing in children. Am Fam Physician. Apr 15 2008;77(8):1109-14. [Medline].

Keywords

congenital stridor, congenital croup, chronic congestion, obstruction of airway, noisy breathing, obstruction of trachea, trachea obstruction, micrognathia, bilateral vocal cord paralysis, subglottic hemangioma, airway obstruction, respiratory distress, failure to thrive, increased work of breathing, laryngomalacia, Arnold-Chiari malformation, webs, cysts, papillomata, and laryngotracheoesophageal clefts, subglottic stenosis, double aortic arch, pulmonary artery sling, bronchogenic cyst, tracheomalacia, gastroesophageal reflux, GER, cardio-vocal syndrome, airway foreign body

Contributor Information and Disclosures

Author

Timothy D Murphy, MD, Assistant Professor, Department of Pediatrics, Division of Pulmonology, University of Pittsburgh; Consulting Staff, Division of Pulmonology, Children's Hospital of Pittsburgh
Disclosure: Nothing to disclose.

Coauthor(s)

Clement L Ren, MD,, Chief, Division of Pediatric Pulmonology, Department of Pediatrics, Associate Professor, Golisano Children's Hospital at Strong, University of Rochester, New York
Clement L Ren, MD, is a member of the following medical societies: American Academy of Allergy Asthma and Immunology, American Academy of Pediatrics, American College of Chest Physicians, and American Thoracic Society
Disclosure: Nothing to disclose.

Medical Editor

Thomas Scanlin, MD, Chief, Division of Pediatric Pulmonary & Cystic Fibrosis, Assistant Professor, Department of Pediatrics, Robert Wood Johnson University Medical Group
Thomas Scanlin, MD is a member of the following medical societies: American Thoracic Society and Society for Pediatric Research
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

Charles Callahan, DO, Professor, Deputy Chief of Clinical Services, Walter Reed Army Medical Center
Charles Callahan, DO is a member of the following medical societies: American Academy of Pediatrics, American College of Chest Physicians, American College of Osteopathic Pediatricians, American Thoracic Society, Association of Military Surgeons of the US, and Christian Medical & Dental Society
Disclosure: Nothing to disclose.

CME Editor

Mary E Cataletto, MD, Associate Director, Division of Pediatric Pulmonology, Winthrop University Hospital; Professor of Clinical Pediatrics, State University of New York at Stony Brook; Director of Children's Sleep Services, Winthrop University Hospital
Mary E Cataletto, MD is a member of the following medical societies: American Academy of Pediatrics and American College of Chest Physicians
Disclosure: Shering Plough Pharmaceuticals Honoraria Consulting

Chief Editor

Michael R Bye, MD, Professor of Clinical Pediatrics, Division of Pulmonary Medicine, Columbia University College of Physicians and Surgeons; Attending Physician, Pediatric Pulmonary Medicine, Morgan Stanley Children's Hospital of New York Presbyterian, Columbia University Medical Center
Michael R Bye, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Chest Physicians, and American Thoracic Society
Disclosure: Merck Honoraria Speaking and teaching

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