Tracheomalacia

What is Tracheomalacia?

Tracheomalacia is a health condition where the cartilage in the trachea, or windpipe, is abnormally structured, and this causes excessive collapsing of the trachea. This condition forms about 50% of all inborn illnesses related to trachea. It can be categorized as either diffuse or localized, depending on how widespread the condition is. The distinction also refers to whether the condition is due to disruptions in the trachea’s development (primary forms) or due to factors that come into play after normal development (secondary forms). Primary forms can be either diffuse or localized, while secondary forms are typically localized.

Diffuse primary tracheomalacia is a rare birth defect seen when the cartilage rings in the trachea mature poorly, most often in the lower third of trachea, causing overall weakness of the trachea structure. The condition is more common in premature babies and can go hand in hand with laryngomalacia or can affect the trachea and other airways. If the main bronchi are also affected, it’s known as tracheobronchomalacia. Congenital tracheomalacia may also be found with other birth defects such as heart defects, tracheoesophageal fistula, developmental delay, and gastroesophageal reflux (GER). Some circumstances, like vascular rings could result in the primary defect localized at the trachea’s development.

Secondary tracheomalacia represents acquired forms causing weakness in the tracheal wall, usually due to inflammation or physical pressure from cardiovascular structures or other masses, leading to localized parts of weakened tracheal wall.

In terms of pathophysiology, the trachea’s structural changes impact its functioning. Even a slight narrowing of the trachea according to Poiseuille Law can considerably decrease airflow. Depending on the root cause (primary or secondary tracheomalacia and associated diseases), symptoms may either naturally get better over time or persist, causing significant breathing difficulties.

What Causes Tracheomalacia?

Tracheomalacia, a condition that makes the windpipe (or trachea) weak, can be categorized into three main types. These are: 1) birth defects that affect the strength of the trachea, 2) acquired conditions that weaken the entire or part of the trachea, and 3) conditions that cause outside pressure on the airways.

Birth defects that affect tracheal strength can cause tracheomalacia in babies. Conditions such as Ehlers Danlos and bronchopulmonary dysplasia can lead to a naturally weak trachea. Various childhood syndromes can also be associated with tracheomalacia. Sometimes there’s a link between this condition and other congenital heart diseases or tracheoesophageal fistula, where the windpipe and food pipe are abnormally connected.

Some conditions can interfere with the normal growth of the trachea by exerting pressure on it. One such condition is the presence of vascular rings, which are formed when part of the aorta, the main blood vessel of the heart, doesn’t develop correctly in the womb. This can alter the development of the trachea and esophagus. Other defects that can cause pressure on the windpipe include a right aortic arch, abnormal origins of certain arteries, or misplaced connections between the lungs and heart.

In adults, a condition known as Mounier-Kuhn syndrome can cause tracheomalacia. This is a rare condition where there’s a decrease in elastic fibers in the trachea and main breathing tubes, leading to a weakened and enlarged airway. This condition can result in chronic respiratory symptoms, such as cough, difficulty in breathing, spitting of blood, and wheezing. This syndrome may be associated with other disorders like Ehlers-Danlos syndrome, Marfan syndrome, and loosened skin. Symptoms can range from mild (chronic cough) to severe, including airway damage and blisters, leading to significant difficulty in breathing.

There are several possible causes of tracheomalacia that develops later in life. Inflammation, as seen in conditions such as tracheobronchitis and polychondritis (a rare immune system disorder that involves inflammation and destruction of cartilage), or chronic lung diseases like bronchiectasis (a condition where the bronchial tubes of your lungs are permanently damaged, widened, and thickened) can weaken the airway. Other factors, like long-term intubation, surgery, chest injuries, or foreign bodies, can lead to the disease. Cancers in the respiratory tract may also affect the structure of the airway, causing tracheomalacia.

Lastly, diseases outside the respiratory system that could compress the airway can also lead to this condition. These include cardiovascular masses such as aneurysms (a balloon-like bulge in an artery) and enlarged heart conditions, non-pulsating fixed pressures like large thyroid goiters (enlarged thyroid gland), and chest cancers.

Risk Factors and Frequency for Tracheomalacia

Primary congenital tracheomalacia, a condition that affects the windpipe, is rare and the exact number of people affected is not known. Moreover, it’s likely that the actual figure might be higher as the condition may resolve on its own without diagnosis. In one study where 512 surveillance procedures of the bronchus (air passages into the lungs) were examined, it was found that the condition happens in at least 1 in every 2100 children. Other forms of the condition depend on the underlying issue and occur at different rates.

It’s also important to mention that repetitive intubation (a procedure where a tube is placed through the mouth into the airway) and length of time the tube is kept in are the most common reasons for adults developing tracheomalacia later in life. Furthermore, individuals suffering from COPD (a type of lung disease that blocks airflow), have a 7 to 15% occurrence of tracheobronchomalacia, a similar condition affecting both the windpipe and the bronchi (major air passages of the lungs).

Mounier-Kuhn syndrome, a rare disorder, has only had about 300 reported cases up until now.

Signs and Symptoms of Tracheomalacia

Tracheomalacia is a condition often evidenced by issues like obstructed air flow, the production of a distinctive sound during exhalation known as expiratory stridor, persistent cough, and increased susceptibility to infections in the upper airway. Symptoms may come and go depending on the severity of the disease. In some cases, infants may not show any symptoms; however, they may struggle to swallow solid food. This can sometimes lead to failure to thrive.

The condition usually morphs into noticeable symptoms about 4-6 weeks after birth. The symptoms might become more pronounced during activities that increase airflow, such as physical activity, crying, and feeding. If the symptoms worsen after meals, gastroesophageal reflux could potentially be a factor. Despite these challenges, most children with this condition maintain normal weight. If the trachea is compressed by vascular rings (a group of blood vessels), the child might adapt by extending their head and neck to ease the compression on the trachea.

• Stridor (distinctive sound when breathing out)
• Retractions of supraclavicular and intercostal spaces when breathing in
• Hoarseness or loss of voice (aphonia)
• Respiratory difficulties
• Feeding problems
• Recurrent respiratory infections

These infections, if severe, can cause alarmingly serious conditions such as respiratory distress, pauses in breathing (apnea), bluish skin (cyanosis), and airway obstruction that may necessitate intubation (insertion of a tube to assist in breathing). One positive note is that congenital tracheomalacia, a form of the disease present at birth, usually improves on its own within the first two years of life, as long as there are no other relevant health issues. Abnormal noisy exhalation but normal inhalation are common in children with this condition during a physical examination.

Doctors should take a comprehensive medical history, including questions about any past respiratory problems, details surrounding the child’s birth, and any previous surgical procedures. They should also enquire about the child’s feeding and growth. Young children who experience recurring croup (a respiratory condition that is usually caused by a viral infection and is characterized by a barking cough) and unusual wheezing may have issues with the area below the vocal cords (subglottic). Other conditions might cause similar symptoms, so a thorough examination of the head, neck, and cardio-respiratory systems should be conducted. Some syndromes may present with tracheomalacia, so the doctor should also look for signs of co-existing conditions. For example, some patients with skin hemangiomas (red or purple birthmarks appearing at birth or in the first or second week of life) could also have subglottic hemangiomas.

Testing for Tracheomalacia

Diagnosing tracheomalacia often involves multiple tests. While a doctor typically uses an endoscopy for diagnosis, this is a procedure that allows them to view your body’s internal organs and structures, imaging tests are essential for determining the cause of the condition, particularly for finding external compressions.

One imaging technique that may be used is cine fluoroscopy combined with a contrast swallow. This process provides information about the level of tracheal collapse and outlines any abnormalities. This test is very specific but not very sensitive, so it’s best used in combination with endoscopy – especially when other imaging methods aren’t available.

For a quicker airway assessment, the doctors may use multidetector or ultrafast computed tomography (CT) imaging. This type of imaging can not only check for issues in the airway but also in other structures in the chest when used with a contrast dye. However, keep in mind that CT scan comes with a certain level of radiation exposure and might need sedation in young children, which can affect the airway function. To manage these concerns, doctors might use lower radiation doses or specific types of CT imaging, which allow for normal breathing during the scan.

The primary method for diagnosing tracheomalacia is bronchoscopy, a procedure that allows your doctor to look inside your airways through a thin viewing device. The procedure shows the narrowing of the airway and any change in its shape or structure. At this point, there’s no definitive answer as to whether a rigid or flexible bronchoscopy is better – both have their pros and cons.

Apart from these, other imaging techniques can provide additional information about the disease. For example, an X-ray might not show tracheal abnormalities, but it can reveal other issues like vascular anomalies and respiratory pathologies. Although there’s limited research on the use of dynamic magnetic resonance imaging (MRI) in assessing tracheomalacia, it offers a detailed view of the anatomy without radiation exposure. However, be aware that this process might take a long time and could require sedation in younger children. On the other hand, newer imaging approaches like ultrashort echo-time MRI can provide a dynamic assessment of tracheomalacia in babies without the need for sedation and radiation.

Pulmonary function tests, which measure how well your lungs work, can show an obstructive pattern and support the diagnosis of tracheomalacia. However, they should not be used alone to diagnose the condition.

Treatment Options for Tracheomalacia

Tracheomalacia is a condition that causes the windpipe or ‘trachea’ to be weak or floppy, and its treatment depends on the severity and the presence of other health conditions. This treatment is typically overseen by a team of different health professionals, drawing on the expertise of various specialists.

If a newborn baby has mild tracheomalacia, it’s possible the condition could improve naturally over time. During this period, it’s crucial that the baby is regularly monitored, is given the relevant immunizations and vacinations, and is kept away from passive smoke. In terms of medication, things like bronchodilators, anti-muscarinic agents, mucolytics, and antibiotics are sometimes used, but there’s limited evidence to suggest they’re beneficial.

Managing the flow of mucus and preventing airway infections may be helped by a technique called ‘chest physiotherapy’. It’s also important to prevent and manage gastroesophageal reflux (GER), which is when acid from the stomach washes back up into the gullet. Special feeding regimes need to be followed to prevent the baby from inhaling food into the lungs (‘aspiration’), and to ensure the baby is getting enough nutrients for growth and development.

In adults, tracheomalacia might be discovered by accident during investigation for another condition, and if the person has no symptoms, a ‘watch and wait’ approach is taken. Other health conditions may be present alongside tracheomalacia, like chronic obstructive pulmonary disease (COPD), which also needs treatment. If the usual care isn’t working, continuous positive pressure ventilation (CPAP) could be considered. This device helps with breathing by applying a slight pressure to the lungs. Surgery is considered only as the very last option.

The scientific literature is lacking in solid evidence for how well the currently used treatments work. There’s some support for the use of nebulised hypertonic saline (a type of salt water solution) for clearing mucus, and for prophylactic antibiotics (medication taken to prevent infections). If other conditions are present, they also need appropriate treatment. There’s currently no clear guidance from clinical trials about whether CPAP should be used.

People with severe symptoms, such as periods where breathing stops (apneic spells), failure to thrive, recurring pneumonia, and episodes of blueness (cyanosis), may need surgery. Surgical intervention is particularly likely if the tracheomalacia develops after birth, rather than being present from birth. During surgery, the doctor checks for a tracheoesophageal fistula – an abnormal connection between the trachea and the gullet, and corrects it if needed.

In very severe cases, ‘stenting’ may be considered. This involves placing a tube inside the trachea to prop it open. There are various types of stents available, but all have potential problems. Building up of granulation tissue (excess tissue during healing), damage to blood vessels (vascular eroison), and overgrowth of the tissue lining the windpipe (mucosal hyperplasia) can all occur with different stents. Generally, stents only provide temporary relief, and so are not a long-term solution.

In the past, surgery would often involve tracheostomy, which is where a hole is created in the front of the neck to allow air to enter the lungs. There are two ways to do this, either by traditional surgery or via a needle puncture of the skin (percutaneously). Although tracheostomy can provide relief, it comes with significant risk of complications, so it’s usually reserved for severe cases.

A preferred surgical approach for tracheomalacia in many medical centres is ‘aortopexy’. This procedure lifts the aorta (a major blood vessel) to relieve pressure on the windpipe, and there are a number of ways to perform it. The basic steps involve moving any vessels lying on top of the sternum (breastbone) to its back side, lifting the arteries supplying blood to the lungs, and if needed, suturing or ‘sewing’ the windpipe. This alleviates pressure on the trachea by increasing the space within the chest cavity. Special care needs to be taken to balance the strength of the suture against the risk of bleeding. Recently, a study showed promising results from using aortopexy to address collapse of the posterior (rear) wall of the trachea during breathing.

What else can Tracheomalacia be?

When healthcare professionals are dealing with symptoms consistent with tracheomalacia, such as noisy or difficult breathing (also known as stridor), they explore other conditions with similar symptoms. These include:

• Laryngomalacia, a condition marked by a floppy larynx (voice box), which results in a collapsing airway during breathing in. The symptom often shows a few weeks after birth, tends to worsen over the first few months but typically goes away by age 2.
• Subglottic stenosis, or a narrowing of the airway below the vocal cords. This condition often arises due to repeated trauma from intubations or tracheostomies but can also be caused by autoimmune and connective tissue diseases. The condition is often mistaken for recurrent croup, an inflammation of the larynx and trachea in children, epitomized by a distinctive barking cough.
• Vocal cord paralysis, either inherited or developed later in life. Depending on whether one or both vocal cords are affected, symptoms may range from a weak voice or hoarseness to severe breathing difficulties.
• Epiglottitis, an inflammation of the tissue that covers the trachea, which can cause difficulty swallowing and noisy breathing. This condition requires immediate treatment.
• Inhalation of a foreign object, which typically follows a choking incident. An X-ray can sometimes find the object if it’s visible on the scan, and a procedure to look into the lungs (bronchoscopy) can both diagnose and treat this condition by removing the object.
• Recurrent respiratory papillomatosis, a rare but serious condition in which benign (non-cancerous) tumors caused by certain types of human papillomavirus grow in the airways. This can lead to a hoarse voice and symptoms of upper airway obstruction.

It’s crucial to accurately diagnose these conditions, so the correct treatment can be applied. Methods for diagnosing these problems include flexible nasendoscopy (a procedure that uses a flexible tube with a light and camera attached to it to examine the nose and throat) and bronchoscopy (a comparable procedure that looks into the lungs), in addition to other tests according to the presenting symptoms.

What to expect with Tracheomalacia

For those born with a certain disease and only experiencing mild symptoms, the overall outlook is usually good. Typically, these symptoms fade away around the age of 2. However, those who have other health issues alongside this disease might continue to deal with symptoms until they are older. If someone’s symptoms continue into adulthood, they might find it strenuous to exercise.

The outcome for any additional health conditions depend on the nature of the disease that caused the changes and the severity of the damage.

Possible Complications When Diagnosed with Tracheomalacia

Untreated tracheomalacia can lead to serious complications such as blockage of the airway, repeated lung infections, and failure of growth. The main aim of the treatment is to minimize these complications. However, treatments come with their own set of risks. Issues can emerge shortly after a tracheostomy, including bleeding, infections, damage to the nerve serving the larynx (repeated laryngeal nerve), and accidental creation of an undesired passage. Later problems may include connections forming between the trachea and esophagus or trachea and the nearby innominate artery, and narrowing of the area below the voice box (subglottic stenosis).

Aortopexy, a surgical procedure, also carries some risks, such as air in the chest cavity (pneumothorax), fluid in the pleural space (pleural effusion), lung collapse (atelectasis), paralysis of the diaphragm due to damage to the phrenic nerve, and bleeding.

Here’s a summarised list of complications and risks:

• Airway blockage
• Recurrent lung infections
• Failure to thrive
• Tracheostomy early complications:
  • Bleeding
  • Infections
  • Recurrent laryngeal nerve damage
  • False passage
• Tracheostomy late complications:
  • Trachea-esophageal fistula
  • Fistula between the trachea and innominate artery
  • Subglottic stenosis
• Risks of Aortopexy:
  • Pneumothorax
  • Pleural effusion
  • Atelectasis
  • Phrenic nerve palsy
  • Bleeding

Preventing Tracheomalacia

It’s incredibly important that patients, parents, and primary care doctors are well-versed in the symptoms of the illness as well as the possible complications that could arise. This knowledge helps to prevent worsening of the disease.