eMedicine Specialties > Pediatrics: General Medicine > Pulmonology

Tracheomalacia

Author: Michael R Bye, MD, Professor of Clinical Pediatrics, Columbia University College of Physicians and Surgeons; Acting Director, Department of Pediatric Pulmonary Medicine, Columbia University Medical Center
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Updated: Sep 10, 2007

Introduction

Background

Tracheomalacia is an abnormal collapse of the tracheal walls. It may occur in an isolated lesion or can be found in combination with other lesions that cause compression or damage of the airway. Tracheomalacia is usually benign, with symptoms due to airway obstruction. As such, this condition is often mistaken for chronic asthma or prolonged bronchiolitis.

Pathophysiology

Tracheomalacia may occur as a primary lesion, in which case the cartilage of the trachea is believed to have developed abnormally. This results in tracheal walls that are soft and collapse during respiration. The collapse causes airflow obstruction and wheezing, stridor, or both. If the lesion is extrathoracic, the collapse and airway sounds occur primarily during inspiration. If the lesion is intrathoracic, the collapse and airway sounds occur primarily during exhalation. Because most of the trachea is intrathoracic, exhalatory collapse accounts for most cases of tracheomalacia.

Tracheomalacia may also be found in conjunction with lesions that compress the airway, such as mediastinal masses, vascular slings, and vascular rings. It also occurs with increased frequency in children with chronic inflammation of the proximal airways. Less common in asthma, this etiology of tracheomalacia is more often seen in children with chronic lung disease of infancy, gastroesophageal reflux, or other forms of chronic aspiration. It is also frequently found after repair of a tracheoesophageal fistula.

Frequency

United States

The frequency of tracheomalacia is unclear. The condition appears to primarily derive from a developmental defect in the cartilage of the tracheal wall. Therefore, the lesion usually occurs in infants and young children. It is frequently found in children who have undergone repair of a tracheoesophageal fistula, chronic lung disease of infancy, vascular compression of the airway, or mediastinal masses of sufficient firmness to compress the airway. Children with gastroesophageal reflux, or aspiration from above, have an increased incidence of tracheomalacia. The problem in this last situation is trying to decide which condition is the cause and which is the effect.

International

Data from the Sophia Children's Hospital in Rotterdam (southwest Netherlands), the only facility performing bronchoscopy in children, suggest an incidence rate of 1 case per 2100 newborns.¹

Mortality/Morbidity

Morbidity and mortality are extremely rare. On occasion, tracheomalacia causes enough obstruction to necessitate intervention. This obstruction generally takes the form of episodic severe airway obstruction causing cyanosis. When infants with chronic lung disease of infancy become irritated, they may have what has been called a "BPD fit." This episode usually involves a cry, with either a breath hold or with a sufficient increase in intrathoracic pressure to partially occlude the airway. If the child has tracheomalacia, frequency and severity of these episodes increase.

Race

No racial predilections are known.

Sex

No sex predilections are known.

Age

Because most cases of tracheomalacia appear to be related to a developmental defect in the cartilage of the tracheal wall, the lesion typically occurs in infants and young children. In most children, the tracheal cartilage normalizes, the airway enlarges, and symptoms resolve by 3 years of age (in many before 1 y of age).

• Because tracheoesophageal fistula is usually repaired early in life, the associated tracheomalacia also appears in early infancy, usually shortly after surgery.
• If the tracheomalacia is a result of compression, the patient's age at presentation will depend on the cause of compression. Vascular rings, present from birth, cause tracheomalacia early in life. Other causes of compression, especially tumors, occur later in life.

Clinical

History

• The patient's history reveals a wheeze that usually begins when the individual is aged 4-8 weeks. Although the congenital lesion is present before this time, airflow is apparently insufficient during the first few weeks of life to generate abnormal sounds. The wheeze generally increases with activity and colds and decreases during quiet periods.
• At first, wheezing may be mistaken for a sign of bronchiolitis, especially during respiratory syncytial virus season. As wheezing continues, it may be mistaken for that of asthma or cystic fibrosis. If bronchodilator therapy has been attempted, the history usually indicates no improvement, though the condition of some infants worsens with bronchodilators.
• Unlike most infants with asthma or cystic fibrosis, infants with tracheomalacia are described as "happy wheezers" (ie, those who maintain normal oxygenation and disposition and who grow and develop well, despite the chronic airway noises).

Physical

• The physical findings suggest the diagnosis.
• The baby looks well and happy despite the chronic wheeze.
• Vital signs, including the patient's respiratory rate and oxygen saturation, are normal.
• Lungs have good air entry. The typical abnormality is of a wheeze throughout exhalation that sounds the same in all lung fields. It is a coarse monophonic exhalatory sound, which has been described as exhalatory stridor. No asymmetry to the breath sounds is present. On occasion, the lesion is intrathoracic, and the airway sounds occur in inspiration.
• The patient's voice and cry are normal, unless gastroesophageal reflux is present.
• Because some children have concomitant laryngomalacia, abnormal sounds may be heard on inspiration.

Causes

• As far as tracheomalacia is understood, most cases are isolated and idiopathic.
• Transient defects in tracheal cartilage development are assumed to be the cause of this condition.
• Autopsy data are lacking, and no animal model exists.
• Some children with tracheomalacia have the lesion because of vascular anomalies or other causes of compression of the airway. Others have tracheomalacia as a residuum of repair of a tracheoesophageal fistula, in this case, the patient should have a history of surgery.
• Tracheomalacia may coexist with and complicate other disorders, including cystic fibrosis and bronchopulmonary dysplasia (chronic lung disease of infancy). It is also commonly found in children with gastroesophageal reflux and in children who aspirate from above.

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