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Tracheomalacia

Tracheomalacia is a condition caused by the presence of weak tracheal cartilage that leads to collapse of trachea during breathing. It is characterized by symptoms like shortness of breath and expiratory stridor or wheezing.


Presentation

One of the first symptoms to be noted in children is the typical expiratory stridor noted within 4 to 8 weeks after birth. This noise may increase during conditions which have more demand for air flow like crying and respiratory illnesses. Wheeze may reduce when the child is quiet. While feeding, some children may show difficulty, cough, regurgitation and cyanosis and hence should not be ignored.

In some cases the symptoms of tracheomalacia resemble that of allergic asthma and make diagnosis difficult. Close observation of the patient may show retractions in the supraclavicular and intercostal spaces. Those with a chronic form of tracheomalacia may develop abnormalities in the thoracic region which may be pronounced. This is more common among young children. In severe cases of tracheomalacia, the child may present with difficulty in breathing, dyspnea, cyanosis and respiratory failure. Isolated tracheomalacia is often characterized by the presence of bark-like cough. When the tracheal abnormality is in the extrathoracic region, inspiratory stridor may be noticed.

Prolonged Expiration
  • The weakened area of trachea collapses more easily during expiration and prolongs expiration, or prevents expectoration and causes trapping of secretions.[childrensnational.org]
Winged Scapula
  • The secundary effects like thoracic cage deformities, winged scapula, or scoliosis have not yet been described and are expected to be reduced in comparison to the open technique.[ncbi.nlm.nih.gov]
Disproportionate Dwarfism
  • Abstract Kniest dysplasia is an autosomal-dominant chondrodysplastic condition characterized by disproportionate dwarfism, short trunk, small pelvis, kyphoscoliosis, short limbs, prominent joints, premature osteoarthritis, and craniofacial manifestations[ncbi.nlm.nih.gov]
Opisthotonus
  • Patients with cerebral palsy often develop opisthotonus. The trachea may be pinched between the innominate artery and the cervical spine. This compartmentalized thoracic inlet results in severe tracheomalacia.[ncbi.nlm.nih.gov]

Workup

Imaging techniques like computed tomography (CT scan), fluoroscopy and radiography may help in observing the structure of trachea during respiration and thus in diagnosing abnormalities. Computed tomography is a non-invasive technique that has a sensitivity of about 85% in diagnosing of the condition [9]. Dynamic expiratory CT scan reveals a better picture of the situation when compared to end-expiratory imaging [10]. 

Airway fluoroscopy is another imaging technique for optimal diagnosis of tracheomalacia. It helps to identify the amount of tracheal collapse during quiet respiration and coughing. A tracheal collapse of more than 52% during expiration is considered to be indicative of tracheomalacia. This imaging method also helps to identify the defects in esophagus and blood vessels that lead to a change in the structure of the tracheal wall. Radiography also shows collapse of tracheal lumen and also vascular abnormalities including double aortic arch. But in most cases further diagnosis may be required for a confirmation.

Pulmonary function testing is the recommended laboratory method for diagnosis of tracheomalacia. This method is more commonly used in adults than in children. A pulmonary function test may show a truncated curve for expiration in patients with this condition. 

Endoscopy also helps in a more definitive diagnosis of the condition. It reveals the collapse of the tracheal walls during expiration. Laryngoscopy and bronchoscopy also help in observing the airways during the respiration. Direct visualization of the lumen during respiration helps in confirmation of the diagnosis. A confirmed diagnosis would depend on three factors, change in the shape of the lumen of trachea, extension of the posterior wall, and narrowing of the lumen of trachea. A complete medical history of the patient is equally important.

Anterior Mediastinal Mass
  • Abstract Tracheomalacia is a disorder of the large airways that is often caused by a large anterior mediastinal mass.[ncbi.nlm.nih.gov]
Hypocapnia
  • During this period, a progressive worsening of clinical conditions occurred, despite cortisone and antibiotic therapy, and the patient was transferred to the ICU for dyspnea, hypoxia, hypocapnia and with a diagnosis of pulmonary fibrosis.[ncbi.nlm.nih.gov]
Hypercapnia
  • […] from our experience that the important steps in preventing this complication include 1) expediting the exclusion of upper-airway compromise in intubated infants who have a presentation characteristic of bronchospastic airway disease (hyperinflation and hypercapnia[ncbi.nlm.nih.gov]

Treatment

Tracheomalacia in most of the cases is benign and hence conservative management is the safest treatment. As a first step, noninvasive methods are suggested. This includes physical therapy, humidified air, control of infections and careful feeding. In patients who have difficulty in respiration or needs an intervention, continuous positive airway pressure (CPAP) is recommended [8].

Chest physiotherapy is useful in cases where secretions are not cleared. Coexisting or exacerbating conditions if present, should be treated appropriately. If acute respiratory infections are present which increase the symptoms or affect feeding considerably, corticosteroids are suggested. Non-surgical measures are ideal for mild form of tracheomalacia.

Surgical methods are recommended only in those cases where conservative treatments fail and the patient has severe symptoms. In those forms associated with tracheoesophageal fistula and those caused by vascular defects, aortopexy is suggested to widen the tracheal lumen. In diffuse types of tracheomalacia, the use of stents is beneficial. In children, when the condition resolves with time, the cannula can be removed. An underlying cause like tumors or vascular rings should be corrected surgically. When severe symptoms are present in acquired form of tracheomalacia, stenting and tracheostomy may be helpful. If chronic obstructive pulmonary disease is present along with tracheomalacia, it should be treated first for better results. Widening of the posterior wall of the trachea can be corrected by the use of polypropylene and high density polyethylene mesh [11].

Prognosis

One of the most common causes of tracheomalacia is a developmental defect in tracheal cartilage and hence the condition is more prevalent among infants and young children. In most of the cases, it is a self-limiting condition. Primary tracheomalacia generally resolves by around two years of age as trachea develops [8]. The cartilage becomes stronger and the tracheal collapse ceases. Respiratory diseases, inflammatory or infectious, have more intense symptoms and may prolong treatment. Respiratory difficulties are seen only in association with conditions like bronchitis or croup in mild forms of tracheomalacia. But in moderate tracheomalacia, wheezing, stridor, cyanosis and other factors are more common. Children will have wheezing or stridor with normal breathing in case of severe tracheomalacia and this may be life-threatening in some cases.

Etiology

The disorder is associated with congenital abnormalities like esophageal anomalies, cardiovascular defects and gastroesophageal reflux. About three fourths of the patients with tracheoesophageal fistula is found to have tracheomalacia. Other localized disorders may also cause tracheomalacia including vascular rings, or esophageal artesia [2]. 

Tracheomalacia may be an acquired condition in both children and adults. An asymptomatic period after birth suggests an acquired form. Conditions like presence of endobronchial tube, tracheostomy, chronic tracheobronchitis or inflammation of trachea as in a relapse of polychondritis can result in tracheal abnormality [4]. Prolonged compression of trachea due to benign tumors, aneurysms, cysts or a malignancy may also lead to compressed airways. Tracheomalacia may also develop after procedures like lung transplantation, intubation or tracheotomy.

Epidemiology

Tracheomalacia is found to more common among children. The incidence rate of primary tracheomalacia in children is estimated to be about one in 1445 to 2100 children [5]. A study conducted on 299 patients with airway malacia showed that 26.7% have isolated tracheomalacia [6]. Tracheomalacia is associated with a number of other conditions. About 14 to 58% of the patients with this anomaly was found to have cardiac disorders [7]. It was found to be associated with cardiac defects like double aortic arch, septal defects, patent ductus arteriosus and pulmonary artery sling. About 9.7% of the patients with tracheoesophageal fistula had tracheomalacia [6]. More than half of the infants with tracheomalacia was found to have bronchopulmonary dysplasia and gastroesophageal reflux. An overall delay in development, subglottic stenosis and neurological defects are also associated with this abnormality.

Sex distribution
Age distribution

Pathophysiology

Developmental abnormalities in tracheal cartilage results in soft tracheal walls that collapse and obstruct the airway during respiration. It may lead to wheezing and/or stridor. This sound is prominent during inspiration or expiration depending on the location of the lesion. If the abnormality in the extrathoracic part of the trachea, the sound is heard during inspiration. Defects in the intrathoracic part may lead to airway sounds primarily during expiration. Intrathoracic defects and expiratory sounds are more common as most part of the trachea is placed within the thorax.

Extrinsic compression of the trachea may also lead to its collapse and airway obstruction, a condition referred to as secondary tracheomalacia. Benign tumors, vascular rings and artery slings in the pulmonary region all compress the trachea externally. Any disease that affects the structure of trachea may result in a collapse of the trachea during respiration. In many cases the structural abnormality may not be so prominent and may remain undetected. It not only affects airflow but also leads to impaired clearing of secretions in the trachea.

Prevention

As root cause of the condition is still not clear, definitive preventive measures are not available. But it is possible to prevent the complications associated with tracheomalacia. Continuous monitoring of patients, particularly those who have respiratory infections and illnesses would go a long way in controlling complications. Infants should be fed carefully to prevent aspiration pneumonia. Those who have expiratory noise and breathing difficulty should contact health care provider to reduce problems associated with this disorder.

Summary

Tracheomalacia (TM) is a disorder caused by the presence of weak tracheal cartilage and low muscle tone in the posterior wall of trachea leading to the collapse of airway [1]. This structural abnormality in the tracheal wall results in obstruction of airways [2]. Collapse of the airway is more pronounced when the demand of air is increased as in coughing or crying. The abnormality may be localized or involve the entire trachea. It is one of the most common congenital disorder affecting the trachea. This condition is often seen associated with other congenital abnormalities like gastroesophageal reflux, cardiovascular anomalies and esophageal defects. It is seen in both children and adults, but is more common in premature infants [3]. Tracheomalacia is divided into three different types:

While mild and moderate forms of tracheomalacia remain asymptomatic, severe form of this abnormality can be life-threatening.

Patient Information

Tracheomalacia is a condition in which a structural abnormality in the windpipe causes its collapse during breathing leading to obstruction of airways. Tracheomalacia can be congenital or acquired. Congenital conditions is caused by developmental abnormalities in tracheal structure. Acquired tracheomalacia is caused by diseases that affect the structure of trachea like chronic infections, tumors, inflammation of the tracheal cartilage and prolonged intubation.

Tracheomalacia is seen in infants, young children and adults. One of the most common symptoms is the high-pitched breathing or noisy breathing, especially while breathing out. Recurrent infections in the respiratory tract, shortness of breath, and cough are also seen as symptoms of this condition.

A number of imaging techniques are used to diagnose this condition. Different imaging methods like fluoroscopy, radiography and CT scan help to see the abnormal structure of the trachea. In some of these techniques, both inhalation and exhalation is visualized to see the difference in the structure of trachea while breathing. If the wall of trachea collapses for more than 50% of its normal, it is considered to be indicative of tracheomalacia. Endoscopic methods also help to diagnose the structural defect in trachea.

Severe form of this condition can be life-threatening. But monitoring and appropriate management of the condition helps to resolve the defect. In children, the condition resolves often on its own by the time the child is 24 months old. This is due to the fact that as the child grows, cartilage of trachea also grows and regains its function. Until that time, conservative management including physical therapy and humidified air helps to reduce the symptoms. In some cases when the symptoms are more, surgery may be suggested. Surgery may be used to correct the structure of the trachea either by removing the structures that apply extra pressure on the windpipe or by placing a stent in the trachea to widen the lumen. These stents may be temporary and can be removed after a period of time.

References

Article

  1. Holinger P, Johnston K, Parchet V, Zimmermann A. XCIV Congenital Malformations of the Trachea, Bronchi and Lung. Annals of Otology, Rhinology & Laryngology. 1952;61(4):1159-1180.
  2. Beasely SW, QI BQ. Understanding Tracheomalacia. J Paediatr Child Health 34.3 (1998): 209-10. Print.
  3. Jacobs I, Wetmore R, Tom L, Handler S, Potsic W. Tracheobronchomalacia in Children. Archives of Otolaryngology - Head and Neck Surgery. 1994;120(2):154-158. 
  4. Adliff M. Treatment of Diffuse Tracheomalacia Secondary to Relapsing Polychondritis With Continuous Positive Airway Pressure. Chest. 1997;112(6):1701. 
  5. Boogaard R. Tracheomalacia and Bronchomalacia in Children : incidence and patient characteristics. Chest. 2005;128(5):3391. 
  6. Masters I, Chang A, Patterson L et al. Series of laryngomalacia, tracheomalacia, and bronchomalacia disorders and their associations with other conditions in children. Pediatr Pulmonal. 2002;34(3):189-195. doi:10.1002/ppul.10156.
  7. Blair G, Cohen R, Filler R. Treatment of tracheomalacia: Eight years' experience. J Pediatr Surg. 1986;21(9):781-785.
  8. Carden K. Tracheomalacia and Tracheobronchomalacia in Children and Adults : an in depth reveiw. Chest. 2005;127(3):984. 
  9. Frey E, Smith W, Grandgeorge S et al. Chronic airway obstruction in children: evaluation with cine-CT. American Journal of Roentgenology. 1987;148(2):347-352. 
  10. Baroni R, Feller-Kopman D, Nishino M et al. Tracheobronchomalacia: Comparison between End-expiratory and Dynamic Expiratory CT for Evaluation of Central Airway Collapse. Radiology. 2005;235(2):635-641. 
  11. Collard P, Freitag L, Reynaert M, Rodenstein D, Francis C. Respiratory failure due to tracheobronchomalacia. Thorax. 1996;51(2):224-226.

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Last updated: 2019-07-11 21:57