The trachea (windpipe) is the airway, a tube made up of cartilage (the firm tissue in the ear) which starts just below the larynx (voice box) and continues down behind the breastbone then splits into two smaller tubes, called bronchi, which lead to each lung.
With normal breathing, as air is drawn into the lungs, the trachea grows wider and longer. An unhealthy or abnormal trachea, however, may behave differently. The trachea and bronchi can become narrowed or blocked for various reasons, including birth defects, inflammation, injury, or tumor. These conditions can seriously affect the ability to breathe.
Types of Tracheal Disease
The two most common tracheal disorders are tracheal stenosis and tracheomalacia:
Tracheal stenosis is narrowing of the trachea, and as such narrowing occurs, it is more difficult to draw air into the lungs. The degree of tracheal stenosis can range from mild to severe. Patients who have a more severe stenosis may require a tracheostomy tube inserted below the area of obstruction to be able to breathe.
Tracheal stenosis is most commonly caused by inflammation and scarring that follows intubation, insertion of a breathing tube into the trachea during surgery, or when there is the need for mechanical ventilation (respirator). It can also be caused by:
- Autoimmune disorders (such as amyloidosis, pulmonary sarcoidosis, Wegener’s granulomatosis)
- External injury (trauma) to the chest or throat
- Infections (such as tuberculosis)
- Radiation therapy
- Thermal burns /caustic injuries
- Tumors in or pressing against the trachea
Patients with tracheal stenosis do not always exhibit symptoms. However, a patient with tracheal stenosis may present with:
- Asthma (wheezing)
- Bluish tint to skin color, or in the mucous membrane of nose or mouth
- Coughing or hoarseness
- Coughing up blood
- Difficulty breathing
- Frequent cases of pneumonia or other upper respiratory infections
- Respiratory distress
- Shortness of breath
- Stridor, or high-pitched breathing sound
Depending on the severity, location, length and cause of tracheal stenosis, treatment options will vary. Some of the most common surgical options include the following:
- Bronchoscopic tracheal dilation: Through a bronchoscope (a light used to examine the inside of the airway), a balloon or tracheal dilator is used to widen (stretch) the trachea, providing immediate relief of the airway obstruction and allowing the thoracic surgeon to precisely identify the extent and severity of the narrowing.
- Laser bronchoscopy: Through a bronchoscope, scar tissue is burned away with a laser beam; the procedure provides short-term but immediate relief of the obstruction.
- Tracheobronchial airway stent: The tracheal narrowing is propped open with a fine metallic expandable stent inserted into the airway through a bronchoscope.
- Tracheal resection and reconstruction: The area of tracheal scarring and constriction is cut away (resected), and the two remaining ends of the trachea sewn back together resulting in an unobstructed airway.
Tracheomalacia is a condition in which the cartilage in the wall of the trachea softens resulting in a floppy or weak airway that collapses with breathing and makes breathing difficult.
Tracheomalacia has multiple causes. Infants may be born with the disorder, or adults may develop it later on in life. The most common causes of tracheomalacia include:
- Damage to the trachea or esophagus caused by surgery or other medical procedures
- Damage caused by a long-term breathing tube or tracheostomy
- Chronic infections (such as bronchitis)
- Gastroesophageal reflux disease (GERD)
- Inhaling irritants
- Polychondritis (inflammation of cartilage in the trachea)
The symptoms of tracheomalacia include:
- Abnormal/irregular breathing noises (such as high-pitched or rattling sounds)
- Chronic cough/hoarseness
- Difficulty swallowing, especially solid foods
- Recurring respiratory tract infections
- Shortness of breath
In many cases, tracheomalacia gradually improves without any treatment at all as the trachea becomes more rigid and less “floppy”. However, patients who suffer from frequent respiratory infections should be closely monitored. Their options for treatment may include the following:
- Chest physical therapy: Non-invasive techniques that include lightly tapping on the chest to break up mucus, and deep breathing exercises.
- Continuous positive airway pressure (CPAP): Through a face mask, air under mild pressure forces the trachea to remain open during breathing.
- Tracheobronchial airway stent: The trachea is propped open with a thin metallic expandable stent placed into the airway through a bronchoscope.
- Tracheal resection and reconstruction: After removal of the scarred, floppy portion of the trachea, the remaining ends of the trachea are joined back together.
- Tracheoplasty: A surgical procedure that provides support to the weak/floppy trachea, preventing its collapse during breathing. The procedure uses plastic mesh or surrounding tissue as support, and the length of the floppy trachea is sutured to it so that the airway is held in an open configuration during the breathing cycle.
- Tracheostomy: An incision in the trachea is made, and a tube is inserted into the airway to relieve the obstruction to breathing.
Diagnosis of Tracheal Diseases
After completing a medical history and general physical examination, the physician may perform one or more of the following procedures to determine whether there might be tracheal stenosis or tracheomalacia present:
- Bronchoscopy—a procedure in which a lighted tube is inserted into the windpipe and allows the physician to examine the inside of the trachea and bronchi (the air passages leading to the lungs). The procedure enables the physician to make a precise diagnosis and measure the length of the abnormal airway segment.
- Chest X-rays depict the interior of the chest, and CT-scans produce a series of images of the inside of the body, taken from different angles and depths, to reveal a high level of detail, particularly of the trachea and any narrowing or tracheomalacia that may be present. To ensure that the blood vessels and organs show up clearly in these scans, dye may be swallowed or injected into a vein during performance of the scan.
- Dynamic 3D Chest CT-scans provide more detailed imaging of the area of tracheal narrowing. This is a non-invasive procedure performed with the patient inhaling and exhaling.
- Pulmonary Function Tests, or PFTs, assess the function and strength of the lungs. For the most common of these, after forcefully blowing air into a tube, a machine called a spirometer measures the volume of air the patient is able to hold in the lungs, and the speed with which that can be blown out (exhaled). Compared with normal values, an obstructed airway can be identified.