The subglottis is just below the vocal cords at the bottom of the voice box (larynx). It is the narrowest part of a child’s airway. Subglottic stenosis is a narrowing of the subglottic airway. Doctors do not know how many children are affected by subglottic stenosis, but we see around 200 children with the condition each year at Great Ormond Street Hospital (GOSH).
What causes subglottic stenosis?
There are a number of causes of subglottic stenosis, which may be present at birth (congenital) or acquired later.
Congenital subglottic stenosis is caused by problems in the formation of the cartilage ring that make up the windpipe. We do not know what causes this to happen during pregnancy.
Most acquired cases of subglottis stenosis occur in the first few months of life and can result from needing a breathing tube inserted into the airway (intubation), particularly when a baby is born prematurely. The number of babies affected in this way is reducing as intubation techniques improve.
Subglottic stenosis can also happen following damage to the area or infection. Gastro-oesophageal reflux– where acid from the stomach travels back up the foodpipe to the throat – can cause irritation leading to narrowing. In severe cases, subglottic stenosis can occur quickly, causing a life threatening airway problem.
What are the signs of subglottic stenosis?
The most common symptom is highpitched noisy breathing (stridor). Shortness of breath can also occur, especially when a child is active. The breathing difficulties may lead to difficulty feeding, failure to thrive or recurrent episodes of croup.
How is subglottic stenosis diagnosed?
Children will need a clinical examination by an ear, nose and throat (ENT) specialist doctor. The doctors will ask parents about their child’s symptoms and past medical history. The diagnosis of subglottic stenosis is usually confirmed using a procedure called a microlaryngoscopy and bronchoscopy (MLB).
An MLB is a test that allows the doctor to look into the child’s airway (larynx and bronchi) using a small telescope and light. This is contained in a piece of equipment called an endoscope.
Subglottic stenosis is graded from one to four, depending on the severity of the airway blockage. Grade one is the least severe form and grade four is the most severe.
How is subglottic stenosis treated?
The options for treatment depend on the severity of the child’s symptoms and the grading of the subglottic stenosis.
Children who have mild subglottic stenosis with few problematic symptoms, may not need any treatment. They will however need regular reviews with the ENT specialist doctor, usually with regular MLB procedures.
If a child has more severe subglottic stenosis or the symptoms are causing problems, there are a number of options for treating the condition surgically. Operations include dilatation (widening) the airway or laryngotracheal reconstruction.
Very severe subglottic stenosis which is interfering with a child’s breathing, may require a tracheostomy(artificial opening through the skin into the windpipe). The tracheostomy is placed below the narrowed section, allowing the child to breathe while other treatment options are considered.
What happens next?
The narrowed section of airway will be monitored closely using MLB, whether or not a child has had surgery. The MLB procedure can show whether the narrowing is getting better, that is, the airway is widening, and that any surgical treatment has been successful.