Crepitus and pleural friction noise are pathologies that occur in the respiratory tract. This article will identify the differences between the two violations. To begin with, you should consider what crepitation is.
Crepitus
This phenomenon appears at the height of inspiration in the form of cod and resembles the sound obtained by rubbing a small bundle of hair over the ear. The main condition for the formation of crepitus is the accumulation of viscous secretion or fluid in the lumen of the alveoli. In this case, the walls of the alveoli stick together in the exhalation phase, and at the height of inspiration, when the air pressure in the lumen of the bronchi is maximally increased, they stick together with great difficulty. Therefore, crepitus is heard only in the final phase of respiration.
Causes of pathology
Crepitus is observed in the following cases:
- when the lung tissue becomes inflamed in the first and third stages of croupous pneumonia;
- with infiltrative pulmonary tuberculosis;
- with congestion occurring during pulmonary circulation, the result of which was a weakening of the contractile function of the muscles in the left ventricle;
- with pulmonary infarction.
Crepitus with a decrease in the elasticity of the lung tissue is most often heard at the first deep breath in the lower lateral parts of the lungs in elderly people. With compression atelectasis, transient crepitus may also appear.
Crepitus Diagnosis
The acoustic properties of crepitus can often resemble finely bubbly moist rales, which are formed during accumulation in the bronchioles or in the smallest bronchi of liquid secretion. Therefore, its difference from wheezing is of great importance in terms of diagnosis. Persistent crepitus indicates the presence of inflammation in the lungs, and small-bubbling rales are indicative of the inflammatory process only in the bronchi or congestion in the lungs.
Differential diagnostic signs of crepitus:
- wheezing is heard both on inhalation and on exhalation; after coughing, they may intensify or disappear;
- crepitus is heard only at the height of inspiration, its strength and character after coughing does not change.
Pleural friction noise
Under physiological conditions, parietal or visceral pleura sheets have a smooth surface and constant wet lubrication. Therefore, in the process of breathing, their glide occurs silently. Pathological conditions of various etiologies lead to the fact that there is a change in the physical properties of the petals and conditions are created that promote stronger friction between them. As a result of this, a peculiar additional sound arises, called the pleural friction noise.
Causes
One of the conditions for the appearance of such noise is the roughness or roughness of the pleura when it is inflamed. These noises appear due to the deposition of fibrin or subsequently inflammation and the subsequent development of scars (connective tissue), adhesions between the leaves. The surface of the pleura leaves becomes uneven when the cancerous nodules or tuberculous tubercles are spilled onto them. There is a pleural friction noise during sharp dry leaves due to the rapid loss of a large amount of fluid by the body during severe, indomitable diarrhea or massive blood loss.
Diagnostics
The pleural friction noise is heard both on inspiration and on exhalation. It differs in volume, strength, location, duration of existence. With a sharp dehydration of the body or at the initial stage of development of dry pleurisy, the noise is more gentle, quiet and resembles in its timbre the sound that occurs when friction occurs between pieces of silk fabric. During the period of active treatment of dry pleurisy, it changes its character and the pleural friction noise resembles crepitus or small bubbling rales, and in some cases, a crunch of snow. The friction noise of the pleural sheets with exudative pleurisy becomes coarser. He recalls not only the sound of snow, but also the creak of a leather belt. Typically, such low-frequency oscillations can be detected by palpation.
Duration
Duration may vary. With rheumatism, for example, for a couple of hours, noise can be observed, and then a gap and reappear after a while. With dry pleurisy having a tuberculous etiology, pleural friction noise can continuously be heard for several days, and with exudative pleurisy - more than a week. In a number of patients, after they have transferred pleurisy, gross cicatricial changes in the pleura and an uneven surface of the leaves may appear. This can lead to noise being heard for many years.
Listening places
Listening locations may also vary. It depends on where the focus of inflammation is located. In the lower lateral part of the chest, it is detected most often, since here the lungs move as much as possible when breathing. With rare exceptions, you can listen to him in the area where the apex of the lungs is located. This happens when a tuberculous process develops in them and inflammation spreads to the pleural sheets. If the inflammatory focus is localized in the pleura, which is in contact with the heart, so-called pleuropericardial murmurs may appear, heard not only during inhalation and exhalation, but also during diastole and systole of the heart. They are heard more distinctly, in contrast to intracardiac noises, at the height of a deep breath, when pleural sheets adhere more tightly to the heart.
So, itβs worth summing up what are the main differences between pleural friction noise and crepitus:
- With crepitation, wheezing disappears for a while or changes its character after coughing, and the noise of friction does not change and does not disappear after it.
- If you press the sternum sufficiently with a stethoscope, the pleural friction noise amplifies, and the character of wheezing in this case does not change.
- Crepitus is heard only at the height of inspiration, and the pleura noise is heard in both phases of respiration.
- When mouth and nasal breathing is held, pleural noise due to displacement of the diaphragm and sliding of the leaves can be heard by the ear, and crepitus due to the fact that there is no air movement along the bronchi, is not heard.