rattle

Classification

We distinguish:

• crackling rales which are noises heard during the breathing of an individual with a lung disease, and resembling the noise produced by burning salt. Laennec, thanks to the development of his stethoscope, succeeded in hearing these noises distinctly for the first time. They are comparable to those of the crackle, corresponding to the tactile or sometimes audible sensation heard when an individual walks in the snow. Crackles are fine, rapid, dry noises, equal to each other, and regularly spaced. They appear at the end of inspiration, that is to say when an individual fills his lungs with air. They are particularly found in patients with the beginning of pneumonia, and are comparable to the noise caused by the rustling of a lock of hair. Laennec distinguished:
  • The returning crackling rattle, corresponding to the larger, more humid rattle.
  • The crackling rale itself, which is heard in the third stage of pneumonia. In fact, it is more of a sub-crackle rale present when there is a pulmonary infection, and therefore results from a filling of the pulmonary alveoli with serosity (inflammatory fluid). The crackling rales are either localized as in pneumonia, or diffuse as in pulmonary fibrosis, or even in pulmonary edema. They can be the result of damage to the alveoli and the lung tissue itself.
• rales under crackles which are noises comparable to crackling rales, but do not have all the characteristics. They are audible when there is pulmonary congestion. On the other hand, they are less dry and appear more at the time of expiration than inspiration.
• Lesnoring rales also called ronchus, are perceived mainly during expiration (the patient empties his lungs), and sometimes during inspiration. The noise of the snoring rattle is comparable to snoring. Ronchus come from the accumulation of secretions in the large bronchi, particularly at the time of bronchitis. This hypersecretion of mucus (protective fluid) is located in the mucous membranes of the bronchi (layer of cells protecting the inside of the bronchi from contact with air). The overproduction of mucus is permanent, and reappears constantly (period exceeding three months and extending over at least 2 years), this in the absence of any other disease of the respiratory system. It results in a chesty cough, and expectorations (expulsions) of phlegm, containing debris of dead cells, and sometimes pus.
• sibilant rales predominate as with snoring rales on expiration. They resemble whistling sounds and indicate a narrowing of the bronchi as inasthma among others.