Auscultation as a method of differential diagnosis in bronchial asthma

Bronchial asthma is a chronic respiratory disease. Inflammatory processes occurring in the bronchi disrupt normal breathing, while the general condition of the patient is significantly deteriorating.

Auscultation is of great importance in the diagnosis of bronchial asthma . The doctor, listening to the patient’s chest, may hear wheezing or whistling sounds. They have a wide variety of origins and can be heard both on inhalation or exhalation, and when holding the breath.  

Correct interpretation of what the doctor hears during the auscultation process helps in the diagnosis and treatment of AD.

What is auscultation

Auscultation refers to the diagnostic methods used in bronchial asthma. With it, the doctor listens to the patient, identifying and classifying the murmurs in the lungs.

Two methods of auscultation are practiced:

  1. Straight. Listening to the lungs is done without any devices. Most often, the doctor simply puts his ear to the patient’s chest.
  2. Indirect. This method requires a special device – a stethoscope.

In modern medicine, only the second method is used, considering the first insufficiently reliable.

Auscultatory the doctor is able not only to make a preliminary diagnosis, but also to determine the severity of the disease.

Features of auscultation

In modern medicine, the indirect method of auscultation is used. The attending physician carefully listens to the patient’s breathing both on inhalation and exhalation and analyzes what he hears.

The results must be entered into the patient’s outpatient card. For a more complete picture, the procedure is performed while standing and sitting.

In some cases, when the patient is unable to stand or sit for health reasons, the procedure can be performed in the supine position. Since it is in any case important to listen to all areas of the chest, the patient should take deep, full breaths in and out.

In some cases, normal listening is not enough. For such situations, there is a special technique – bronchophonia . The essence of this method lies in the fact that the patient whispers words that include the sounds “R” and “H”.

If the doctor clearly distinguishes the spoken words through the statoscope, it means that the patient has a certain seal in the lung area. It also suggests a cavity in the lungs. These signs make it possible to diagnose bronchial asthma.

In the case of listening to a healthy patient, the doctor is not able to distinguish any words (only some hissing sounds).

After completing the procedure, the doctor systematizes what he heard and draws conclusions based on the following criteria:

  • compares the same noise in both lungs at symmetrical points;
  • determines the type of noise, according to the accepted classification;
  • detects the presence of extraneous noises uncharacteristic for BA.

Despite the fact that modern medicine has such modern diagnostic methods as radiography, bronchography, etc., auscultation is mandatory. And all other examinations are assigned only according to its results.

Breathing noises and wheezing in bronchial asthma

The auscultatory data obtained by the doctor during the initial examination of the patient, as well as during an attack of bronchial asthma, are of great diagnostic value.  

There are three types of noise:

  • main:
  • side;
  • noises due to friction of the pleura.

Basic noises

These are the noises generated by breathing. In medicine, there are 2 types of breathing:

  • bronchial;
  • vesicular.

In order to assess bronchial breathing, the following zones should be listened to:

  • above the larynx;
  • over the trachea;
  • over the bronchi;
  • in the area of ​​the location of the seventh cervical vertebra.

In the presence of bronchial asthma, rough sounds are heard on auscultation. For correct diagnosis, it is important to listen to it both on inhalation and exhalation. In this case, the exhalation is always coarser and takes longer.

If you listen to other areas, the sound has a different timbre. It corresponds to vesicular respiration. The air entering the alveoli straightens their walls with a characteristic sound.

A single clinical picture can be distinguished for BA. If there is a weakening of respiratory sounds during an attack, this means that acute emphysema or pneumothorax of the lungs has developed.

“Silent lung” (there is no breathing in any of the departments) indicates a large mucous plug or severe bronchospasm, requiring urgent resuscitation.

If the wheezing is monotonous, evenly distributed over the entire surface of the lungs, this indicates bronchospasm.

A combination of high and low wheezing indicates prolonged exacerbation.

If the patient has a mild stage of obstruction, the noises are clearly audible only on exhalation. As the condition worsens, they begin to listen and on inhalation.

Side noise

On auscultation of bronchial asthma, crepitus and wheezing are emitted.

Wheezing, in turn, is also usually classified:

  1. Dry. They arise due to the narrowing of the lumen of the bronchi. This occurs with bronchial asthma, pneumonia and other inflammatory diseases. Dry wheezing may appear or disappear. They are heard both on inhalation and exhalation.
  2. Wet. Occur in case of excessive accumulation of sputum. Wheezing is an indicator of the presence of fluid in the lungs. It occurs when air passes through it. That is why such noise resembles a gurgle. These wheezing sounds are best heard during inhalation, but an experienced doctor can hear them at any stage of breathing.

By tonality, there are:

  1. High. They are characteristic of small bronchi.
  2. Low. They arise in large and medium bronchi.

Wheezing can be heard only on inhalation or only on exhalation. In some cases, they can be heard even without the aid of any instruments. For example, with an attack of bronchial asthma, wheezing is heard at a distance of several meters from the patient.  

By localization, point is distinguished (for example, with tuberculosis) and spread throughout the cavity (bronchial asthma).

Crepitation should be singled out separately. It occurs in the alveoli when a specific fluid accumulates there , which is formed during inflammatory processes. Crepitation is well audible on inhalation. It does not disappear after coughing.

Noises arising from friction of the pleura

The pleura in its normal state is a flat surface. If breathing is not complicated by any pathologies, the pleural sheets easily and soundlessly slide over each other.

In the presence of inflammation, a different picture arises. Irregularities form on the surface of the pleura. On auscultation of the lungs, the doctor will hear a crackling sound caused by the friction of these irregularities against each other.

Very often bronchial asthma develops with toxic damage to the pleura. It becomes dry and leaf nodules form on the surface.

The noise generated by them is easily audible both on inhalation and exhalation. With this type of pathology, the patient may experience pain.

There are several main differences between pleural friction and wheezing:

  1. The more the statoscope is pressed against the patient’s body, the more clearly the crackling is heard.
  2. If the patient coughs frequently, wheezing changes its strength and tone. In the event of friction, the sound remains unchanged.

For a clear differentiation, doctors use a special technique: first, they ask the patient to breathe in deeply and hold the air, and then push out the stomach strongly, imitating abdominal breathing. In this case, friction of the pleural petals occurs among themselves.

The difference between asthma and other pathologies in the auscultatory picture

Through auscultation, the physician can distinguish bronchial asthma from other diseases associated with airway inflammation.

For bronchial asthma, uniform, localized rales are characteristic of the entire surface. And, for example, with tuberculosis, their localization is pointwise.

During the period of pneumonia, high- pitched noises are clearly heard . With bronchial breathing (which indicates the presence of voids in the lung), a noise of a low timbre and low volume is possible.

In acute emphysema, a decrease in noise is noted. Moist wheezing, weakened breathing.

Bronchitis is characterized by vesicular breathing with dry wheezing and crepitus.

With pleurisy, the main distinguishing feature is the noise that occurs when the pleura is rubbed. If the disease is exudative, vesicular respiration is possible.

Despite the fact that with the help of auscultation it is possible to determine the pathology that has affected the airways, the final diagnosis is made only after other, more informative modern studies.


Auscultation in bronchial asthma is of great diagnostic value. Any other examination (X-ray, bronchography, etc.) is prescribed only after listening to the patient.

The characteristic wheezing and type of breathing allow the doctor to make a preliminary diagnosis and begin timely treatment.

event_note September 6, 2020

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