Squeak · short wheeze
In one sentenceA brief, inspiratory, musical sound. A crackle-like burst often comes before it.
Listen to the same sound in another patient. Breathing rate, chest wall, the pitch of the sound and the number of adventitious sounds vary within realistic limits.
What does it sound like?
A brief "chirp" or "squeak" in mid-to-late inspiration, among the crackles.
Where is it heard?
Usually at the bases, together with crackles.
What causes it?
First, a small airway opens suddenly (a crackle-like click). Then its wall vibrates for a moment (the musical tail). Stiff surrounding lung makes this vibration easier. This is the most plausible explanation, but it has not been shown directly.
Quantitative criteria
- Its duration is short. According to CORSA it rarely exceeds 400 ms, and it may overlap with the wheeze. There is no universal duration threshold.
- In an ILD cohort of 1,000 patients, squawks were associated with bronchiolar involvement and mosaic attenuation (Pereira, 2019).
Clinical meaning
Hypersensitivity pneumonitis is the classic setting. Squawks are also seen in connective tissue disease, bronchiolitis, fibrosis due to microaspiration and other ILDs. Pneumonia is a known setting outside ILD. A squawk does not establish a diagnosis on its own. If exposure history, physiology and HRCT point the same way, it strengthens the possibility that peripheral airway involvement accompanies the interstitial process.
Sounds it can be confused with
A wheeze is longer and often expiratory. A squawk is brief and inspiratory.
The burst at the start of a squawk resembles a crackle, but a musical tail follows it.
If you hear a squawk in a patient with a fibrotic pattern, ask in detail about exposure to pigeons, feathers, mould and damp.
See the reference list for sources.