Subglottic stenosis is a narrowing of the subglottic airway, the portion of the trachea below the voice box and the vocal cords. The condition affects both soft tissue and cartilage support in the region. Subglottic stenosis is either a congenital disorder or a medical condition that develops later in life. Although subglottic stenosis is relatively rare, it can be life-threatening and requires immediate medical attention.
Types of Subglottic Stenosis
The two types of subglottic stenosis are:
- Congenital Subglottic Stenosis
Congenital subglottic stenosis is a rare birth defect, often occurring as part of a genetic syndrome with other symptoms. In this situation, the cartilage in the trachea, or windpipe, never formed completely during fetal development.
- Acquired Subglottic Stenosis
Acquired subglottic stenosis most frequently occurs as a complication following intubation or long-term mechanical ventilation. Intubation is the procedure in which a tube is inserted into the trachea, usually through the mouth, in order to facilitate breathing or the administration of anesthesia. Intubation is most frequently performed prior to surgery or during an emergency situation. Mechanical ventilation occurs when a patient's breathing is assisted by a ventilator, or breathing machine. Some cases of acquired subglottic stenosis may be idiopathic, meaning that their origin is unknown.
Risk Factors for Subglottic Stenosis
While not all of the underlying causes of subglottic stenosis are known, some important risk factors for this disorder have been isolated. In addition to intubation and ventilation, these may include low birth weight in infants, gastroesophageal reflux and sepsis.
Symptoms of Subglottic Stenosis
Because of similarity of symptoms, subglottic stenosis is sometimes at first mistaken for asthma or gastroesophageal reflux. The symptoms of subglottic stenosis may include:
- Stridor, noisy breathing with a high-pitched wheeze
- Respiratory distress
- Recurring croup
- Chronic lung disease
- Inability to breathe without a tracheostomy tube
Diagnosis of Subglottic Stenosis
While respiratory distress, particularly in infants or in patients who have been recently intubated, may be a symptom of subglottic stenosis, occasionally a doctor will detect the problem in a patient who is asymptomatic. After a thorough physical examination, other diagnostic tools may be used to confirm a tentative diagnosis, including X-rays, microlaryngoscopy and bronchoscopy. The patient may also be evaluated by a gastroenterologist who may decide to administer an upper GI endoscopy. Other diagnostic pulmonary tests may also be done.
Treatment of Subglottic Stenosis
In the mildest cases of subglottic stenosis, patients may not require treatment and may just be kept under careful medical observation since they are at greater risk for respiratory problems. When the stenosis, though relatively mild, requires treatment, an airway balloon dilation may be performed. This procedure is similar to an angioplasty in that the pathway is opened by the surgical inflation of a balloon-like device. In cases of severe subglottic stenosis, reconstructive surgery of the larynx and trachea may have to be performed in order for patients to be able to breathe independently.