What Is Tracheal Stenosis

Introduction 

The condition tracheal stenosis can come across as quite daunting, so let’s start by breaking these words down. The word trachea, or the windpipe, defines the main tube in our necks that connects our nose and mouth to our lungs. This tube allows us to convey air between our lungs and the external environment, thus facilitating breathing. The word stenosis means the abnormal narrowing of a blood vessel or structural tube in the body.¹ So in the case of tracheal stenosis, this encapsulates the restriction (stenosis) of a structural tube (the windpipe, or trachea), which obstructs the normal process of breathing. 

Tracheal stenosis is an important condition to understand, specifically in children as it can present more acutely and severely compared to in adults. Therefore, comprehension of its signs and symptoms, in both children and adults is crucial for preventative measures and treatment.

This article will cover a series of concepts including:

1. The anatomy of the trachea 

2. The causes of tracheal stenosis 

3. Signs and symptoms 

4. Assessment and diagnosis

5. Classification 

6. Treatment and management 

7. Rehabilitation and post-care treatment 

Anatomy of the trachea

As mentioned previously, the trachea is the tube in our necks, with the primary function of breathing. It originates from the lower edge of the larynx (the voice box) and connects to two separate tubes in the lungs: the left and main stem bronchi.² If you imagine a tree, its trunk, branches, twigs and leaves, these all represent the structure of the respiratory, or breathing system. The trachea (trunk of the tree) splits into its respective branches, the bronchi. This further divides into smaller structures, the bronchioles (twigs) and alveoli (leaves), which permit the exchange of air in the lungs.

In the neck, there are two main tubes, with differing functions. The oesophagus, or the food pipe and the trachea. The trachea lies just behind the oesophagus.² Now, you may be wondering how food goes down our oesophagus without crushing the trachea? This is due to the formation of 16-20 ‘C-shaped’ cartilage rings that protect and support the trachea.²

The trachea contains four main layers:²

• The inner mucosal layer 
• The submucosa 
• The musculocartilaginous layer 
• Muscle/ adventitia

The inner mucosal layer contains cells which secrete mucus that lines the inner lining of the trachea. This process acts as a first-line defence, enabling the entrapment of dust and foreign particles before they reach the lungs.² Additionally, this layer contains another form of cells which has tiny hair-like projections that sweep this mucus and its contents away from the lungs.² This is a common experience, and you may have encountered this if you have ever coughed up mucus or phlegm. 

The submucosal layer is found just underneath the mucosa and is made up of nerves, blood vessels and elastic tissue. The elastic tissues provide structural support and flexibility to the trachea during breathing.³

As per the name, the musculocartilaginous layer contains both muscle and cartilage which provide physical support to the trachea and as aforementioned, prevent the collapse of the trachea during food ingestion.³

Lastly, the adventitia, the final layer of the trachea, contains fundamental muscles that anchor the trachea to surrounding structures and essentially hold it up to allow air into the lungs.²

The causes of tracheal stenosis

There are two types of tracheal stenosis: acquired or congenital.⁴

Acquired tracheal stenosis commonly results from either injury or illness. These include :

• Trauma or injury to the throat or chest 
• Bacterial or viral infections 
• Autoimmune disorders (such as sarcoidosis, papillomatosis, granulomatosis and amyloidosis) 
• Tumours (both benign- non-cancerous or malignant- cancerous) 
• Radiation therapy involving the neck or chest

Each of these causes result in local inflammatory processes that subject the trachea to narrowing via the hypersecretion of mucus, or obstruction via the formation of plaques and tumours.

Congenital tracheal stenosis is an extremely rare condition that is found at birth. It occurs in 2 out of 100,000 infants.⁴

Signs and symptoms 

Signs are observable characteristics of people experiencing a certain condition, which can be noted by a healthcare professional during an examination. Symptoms are feelings, emotions or general physical observations experienced by the person during the presence of the condition. 

For this article, the focus will be targeted towards symptoms, which is what the patient may observe or experience. However, it is also important to see a medical practitioner, which will help to differentiate the signs and symptoms from other conditions.

Some typical symptoms of tracheal stenosis involve : 

• Difficulty breathing including wheezing, coughing or shortness of breath
• A high-pitched squeal coming from your lungs when inhaling 
• Recurrent infections such as pneumonia 
• Asthma which is difficult to treat
• Chest congestion 
• Pauses or breaks in breathing (apnoea) 
• A blue colour of the skin or mucous membranes of the mouth or nose

Specific symptoms in children involve:⁴

• Difficulty breastfeeding or bottle feeding
• Abnormal or extreme tiredness after feeding 
• Choking or difficulty breathing whilst eating 
• Noisy breathing 

Tracheal stenosis is predominantly life-threatening in children compared to adults,⁴ however in both cases, the airway is restricted and can cause impairments in breathing. Therefore, a healthcare professional must assess the severity of the stenosis and provide you with options for interventions that may aid the ease of your breathing and your quality of life. 

Differentiating tracheal stenosis from subglottic stenosis 

Both of these conditions cause the narrowing of the upper airway, however subglottic stenosis only involves the portion of the airway just below the vocal cords (in the larynx) and above the trachea.⁵

Assessment and diagnosis 

Common investigations and diagnosis for tracheal stenosis comprise the use of a tube with a camera to look inside the trachea. This is called flexible or rigid laryngoscopy or bronchoscopy.⁶ This investigation is often paired with imaging techniques such as CT scans⁶ to get a better look at the extent of the obstruction and how best to manage it. 

Other tests that may be ordered to diagnose tracheal stenosis are:⁷

• Lung function tests (assessing the response of the trachea and lungs after activities)
• Chest x-ray 
• Biopsy (to provide information on tumours or plaques)

Classification and grading systems

According to the Myer-Cotton grading system, stenosis is based on anatomical parameters and the degree of obstruction of the trachea. There are 4 grades, with each subsequent stage encapsulating a higher extent of obstruction.⁸

Grade 1: 0-50%

Grade 2: 51-70%

Grade 3:71-99%

Grade 4: 100%

Treatment and management 

Following evaluation of the severity and extent of the tracheal stenosis, a specialised medical practitioner, called an otolaryngologist, will discuss the potential treatment options and allow you to choose one that works best for you. They will also explain the procedure of choice in depth, walk you through what will happen on the day and encourage you to ask any questions or contact them if you have any concerns.

In tracheal stenosis, most of the treatment options are minimally invasive, meaning that they are medical procedures (including surgery), however, they utilise equipment that reduces recovery and rehabilitation times post-intervention.

Some of the procedures include:

Laser surgery 

This procedure utilises a laser to remove any scar tissue that may be restricting the airway. Although this is a procedure that can provide short-term relief, it is not considered to be a definitive treatment.⁹

Widening of the trachea 

Similar to laser surgery, this treatment is not considered a permanent solution to tracheal stenosis. A balloon or dilator is used to expand and widen the airway, thus providing more area for air to pass through.⁹

Airway stenting 

Stenting involves the insertion of a small tube of metal or a mesh to allow patency of the trachea. This is considered to be a more viable long-term solution.⁹

Full tracheal resection and reconstruction 

If all other options are not possible or feasible, then tracheal resection is a definitive treatment involving the removal of a section of the windpipe and connecting the two ends.¹⁰

Rehabilitation and post- care treatment 

Post-procedure, the typical recovery period takes several weeks. In this interim period, your doctor may recommend rest and avoidance of strenuous activity. They may also provide prescriptions for pain and the prevention of infections. Follow-up appointments will be arranged to monitor your progress and alter your treatment plan if required.¹¹

Summary

To summarize, tracheal stenosis is a condition that demands our attention and understanding. By recognising its causes, symptoms and the importance of timely diagnosis, we can provide better care and support for affected individuals. This article has aimed to shed light on tracheal stenosis and its various facets, emphasising the significance of early intervention, personalised treatment and ongoing care in helping individuals breathe easier and have an improved quality of life.