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CHAPTER 43

Tracheomalacia

Vivien M. McNamara
David P. Drake

Introduction Table 43.1: Causes of tracheomalacia.
The normal trachea is supported by up to 20 horseshoe-shaped cartilage Primary Cause usually unknown.
rings completed by a posterior membranous wall. In tracheomalacia, Absent or deformed tracheal cartilage rings.
these cartilages may be abnormally shaped, small, or even absent, with Secondary Oesophageal atresia with or without tracheo-oesophageal
a detrimental effect on the support of the trachea. The anteroposterior fistula.
(AP) diameter of the tracheal lumen becomes reduced, especially dur- Extrinsic vascular compression: vascular ring (e.g., double
ing periods of increased airflow. The dynamic movement of the malacic aortic arch), aberrant vessel (e.g., anomalous innominate
segment becomes most pronounced during the exertion of feeding, artery or pulmonary artery sling), or (mediastinal mass).
crying, or coughing. Symptoms can range from mild to severe, the Prolonged tracheal intubation and ventilation (especially
latter culminating in complete airway obstruction. Mild cases can be cuffed tubes).
managed conservatively with the expectation of spontaneous recovery, Tracheostomy.
usually within the first two years of life. Connective tissue disorder (e.g., Larsen’s syndrome).
Associated medical problems including gastro-oesophageal reflux
and pneumonia, require aggressive treatment. More severe cases Chronic inflammation of the tracheal cartilages occurs with
of tracheomalacia require supportive therapy, diagnostic imaging prolonged intubation or following a tracheostomy. This deleterious
and endoscopic evaluation, and a few may require early surgical effect of mucosal ischaemia caused by the localised pressure of the
intervention to prevent acute life-threatening airway collapse.
intratracheal tubing, especially with cuffed tubes, will compound
Aetiology airway compromise and can delay successful decannulation.
Tracheomalacia may be primary (congenital absence or deformity of Presentation
tracheal rings; the cause is often unknown) or secondary (in conjunc-
Signs and symptoms of tracheomalacia vary from mild to severe and
tion with another pathology) (see Table 43.1). The latter group includes
life threatening (Table 43.2). Many infants exhibit a simple barking
oesophageal atresia (OA), with or without tracheo-oesophageal fistula
cough but otherwise are not troubled by their mild tracheomalacia.
(TOF); a vascular ring (e.g., double aortic arch); vascular compression
For those with OA/TOF, the term “TOF cough” is frequently used to
(aberrant innominate artery or pulmonary artery sling); or extrinsic
describe the characteristic sound made. Expiratory stridor indicates
compression from another source (e.g., a mediastinal mass). It may also
increasing airway obstruction. Crying, agitation, and coughing make
occur in association with prolonged positive pressure ventilation or fol-
the degree of malacic collapse more pronounced. Signs of respiratory
lowing a tracheostomy. It is rarely seen in association with connective
distress, including tachypnoea and intercostal recession, herald further
tissue disorders (e.g., Larsen’s syndrome). Tracheomalacia commonly
airway compromise, and the stridor may become biphasic. Increasing
affects the distal third of the trachea, but can rarely extend into the bron-
severity with infections, including the respiratory syncytial virus (RSV)
chi. When associated with TOF in infants with OA, the malacic segment
infection, is to be expected, and recurrent respiratory sepsis is common.
is located in the middle third of the trachea. Isolated bronchomalacia is
Feeding provides particular challenges, especially in an infant with
usually associated with major cardiac pathologies and is frequently fatal.
tracheomalacia following surgery for OA. Distention of the proximal
The incidence of tracheomalacia is unknown, but it is the most
oesophagus, especially with a solid bolus, may cause compression
common cause of expiratory stridor in infants and children. It is most of the posterior trachea and worsen the symptoms. This is further
often identified secondary to OA/TOF. 1, 2, 3 In affected infants, the
compounded by poor oesophageal motility, anastomotic strictures, and
tracheal cartilage rings fail to develop normally, especially at the site of gastro-oesophageal reflux (GOR). Feeding difficulties may lead to poor
4
the previously ligated fistula. This has long been thought to occur as
weight gain.
a result of extrinsic pressure of the adjacent dilated upper oesophageal
The most severe tracheomalacia is complicated by hypoxia and
pouch, although more recent evidence suggests an early embryological cyanosis. With major airway collapse, following a period of significant
disturbance of tracheal development. 5
respiratory distress, complete obstruction may supervene and the infant
Localised tracheomalacia secondary to extrinsic compression, from
will lose consciousness. At this stage, the collapsed airway will relax
either a vascular ring (double aortic arch) or an aberrant aortic arch
and open again, but with no guarantee that normal ventilation will
or pulmonary artery (PA) vessel, form a small but important group of
resume. These events are often referred to as “dying spells” or acute
affected infants. A double aortic arch results from persistent left and right
life-threatening events (ALTEs). The resulting hypoxia may be severe
dorsal aortic segments, compared to the normal aortic arch in which
and prolonged, leading to bradycardia, cerebral anoxia, asystole, and
there is regression of the right dorsal aorta by week 8 postconception.
even death. Immediate resuscitation, often by the parents, is vital and is
The extent and location of tracheal compression is variable; therefore,
an indication for prompt surgical referral.
so is the degree of malacia. In addition, compression of the oesophagus
Most infants will demonstrate a gradual improvement of symptoms
may present with dysphagia. A double aortic arch will compress both the
over the first year or two of life as the tracheal cartilages become more
trachea and oesophagus.