What Is Stridor and What Causes It?

Stridor is a continuous whistlelike noise during inspiration. This contrasts with wheezing, which occurs during expiration. Anything that causes edema or obstruction in the larynx or the upper trachea can produce stridor. Table 38-1 lists common causes of stridor.

Table 38-1 Causes of Stridor

How Do I Determine If a Foreign Body Causes Stridor?

The history provides the clues to diagnosis. Most older patients have a clear history of choking or gagging if a foreign body (FB) causes stridor. In contrast, when a toddler aspirates an FB, the aspiration episode is commonly unwitnessed and an accurate history can be difficult to obtain. Knowledge of development should make you suspect an FB aspiration if a toddler has the sudden onset of stridor or unexplained cough without prior symptoms. An FB in the esophagus can also cause stridor by compressing the trachea.

What Findings Are Important?

Table 38-2 shows key historical findings for some of the most common causes of stridor. Croup and laryngomalacia are discussed in Chapter 69. Children with croup usually have signs of a viral illness, such as rhinorrhea, cough, and fever. In airway malacia, vocal cord dysfunction, and FB aspiration, the patient usually otherwise appears healthy.

Table 38-2 Key Historical Findings for Most Common Causes of Stridor