Skip to Main Content

Table Graphic Jump Location
Favorite Table | Download (.pdf) | Print
Patient Image not available.

Mr. C is a 32-year-old man with occasional wheezing.

Image not available.What is the differential diagnosis of wheezing? How would you frame the differential?

Wheezing and stridor are symptoms of airflow obstruction. These sounds are caused by the vibration of the walls of pathologically narrow airways. Wheezing is a musical sound produced primarily during expiration by airways of any size. Stridor is a single pitch, inspiratory sound that is produced by large airways with severe narrowing.

Table Graphic Jump Location
Favorite Table | Download (.pdf) | Print
Image not available.Stridor is often a sign of impending airway obstruction and should be considered an emergency.

The differential diagnosis for airway obstruction is large. It is best remembered by an anatomic approach. Stridor may be caused by severe obstruction of any proximal airway (see A through D in the differential diagnosis outline below). A more clinical approach to the differential appears in the algorithm at the end of the chapter.


  1. Nasopharynx and oropharynx

    1. Tonsillar hypertrophy

    1. Pharyngitis

    1. Peritonsillar abscess

    1. Retropharyngeal abscess

  2. Laryngopharynx and larynx

    1. Epiglottitis

    1. Paradoxical vocal cord movement (PVCM)

    1. Anaphylaxis and laryngeal edema

    1. Postnasal drip

    1. Benign and malignant tumors of the larynx and upper airway

    1. Vocal cord paralysis

  3. Trachea

    1. Tracheal stenosis

    1. Tracheomalacia

    1. Goiter

  4. Proximal airways

    1. Foreign-body aspiration

    1. Bronchitis

  5. Distal airways

    1. Asthma

    1. Chronic obstructive pulmonary disease (COPD)

    1. Pulmonary edema

    1. Pulmonary embolism

    1. Bronchiectasis

    1. Bronchiolitis

Table Graphic Jump Location
Favorite Table | Download (.pdf) | Print
Image not available. 

Mr. C has been having symptoms for 1–2 years. His symptoms have always been so mild that he has never sought care. Over the last month, he has been more symptomatic with wheezing, chest tightness, and shortness of breath. His symptoms are worse with exercise and worse at night. He notes that he often goes days without symptoms.

Image not available.At this point, what is the leading hypothesis, what are the active alternatives, and is there a must not miss diagnosis? Given this differential diagnosis, what tests should be ordered?

The presence of wheezing, chest tightness, and shortness of breath are pivotal clues that place asthma at the top of the differential diagnosis. Although asthma is by far the most likely diagnosis, other diseases that could account for recurrent symptoms of airway obstruction should be considered. Allergic rhinitis can cause cough and wheezing but it would be very unusual for it to cause shortness of breath. Vocal cord dysfunction, such as PVCM, is frequently confused with asthma. COPD can also cause intermittent pulmonary symptoms. Table 28–1 lists the differential diagnosis.

Table Graphic Jump Location
Table 28–1. Diagnostic Hypotheses for MR. C.

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.


About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessMedicine Full Site: One-Year Subscription

Connect to the full suite of AccessMedicine content and resources including more than 250 examination and procedural videos, patient safety modules, an extensive drug database, Q&A, Case Files, and more.

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessMedicine

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.