Article by Dr Manasa S, B.A.M.S
Lung sounds are an important aspect of medical examinations, providing clues about your respiratory health.
When you breathe in and out, a healthcare provider uses a stethoscope to listen to these sounds. Normally, air moves smoothly through your airways, creating soft and clear lung sounds. However, when there is swelling, mucus, or blockages, abnormal lung sounds can occur. These include rhonchi, wheezing, stridor, crackles (rales), and pleural rub.
While lung sounds alone can’t diagnose a condition, they help in identifying potential issues ranging from minor illnesses like bronchitis to more serious conditions like pneumonia.
Normal lung sounds
When the lungs are functioning normally, it creates sounds that are soft heard during inspiration and expiration. They are called vesicular lung sounds. Vesicular sounds are heard when there is nothing blocking the airways and the airways are not narrowed or swollen.
A breath sound, also known as a lung sound, is the auditory output produced by the lungs during the processes of inhalation and exhalation. These sounds can be detected either unaided or more commonly through the use of a stethoscope. The practice of auscultation, which involves listening with a stethoscope, allows healthcare providers to discern various sounds associated with inhalation (inspiration) and exhalation (expiration).
Tracheal Breath Sounds
Tracheal breath sounds, characterized by their loud and high-pitched nature, are predominantly heard over the trachea (windpipe). These sounds are frequently described as harsh, akin to air being forcefully blown through a pipe. They are best detected when the stethoscope is positioned on the upper part of the sternum (breastbone) or between the scapulas (shoulder blades).
Bronchial Breath Sounds
Bronchial breath sounds originate from the two primary airways, known as bronchi, which are responsible for delivering oxygen to the lungs. These sounds are audible when the stethoscope is placed over the middle portion of the sternum or centrally on the back between the scapulas. They exhibit a higher pitch compared to other lung sounds, though they are quieter and possess a hollower quality than tracheal breath sounds.
Vesicular Breath Sounds
Vesicular breath sounds are heard over the majority of the lung fields and are generated by the tiny air sacs within the lungs, called alveoli. These sounds are typically soft and low-pitched, predominating during the inspiratory phase. Optimal auscultation of vesicular breath sounds occurs when the stethoscope is placed on either side of the spine below the scapula.
Abnormal breath sounds
The following are common abnormal breath sounds
– Rhonchi
– Rales / Crackles
– Wheezing
– Stridor
– Pleural rub
Let us now understand the abnormal breath sounds briefly
Rhonchi
Rhonchi, the plural form of rhonchus, are continuous, low-pitched sounds most noticeable during exhalation. These sounds, often compared to snoring or gurgling, can shift to different areas of the chest with coughing as mucus moves around. They are sometimes referred to as “sonorous rhonchus.”
Wheeze
A wheeze is characterized by a continuous, high-pitched hissing sound, known as “sibilant rhonchus.” Wheezes are typically more prominent during exhalation but can also be heard during both inhalation and exhalation, especially in conditions like asthma.
Stridor
Stridor presents as a continuous, harsh, high-pitched whistling or squeaking sound. It is usually heard during inhalation.
Crackles (Rales)
Crackles, also known as rales, are described as discontinuous, interrupted, or explosive sounds, reminiscent of rattling, bubbling, or clicking. Fine crackles, or “crepitation,” are brief and high-pitched, whereas coarse crackles have a lower pitch and last longer. Crackles are more commonly heard during inhalation.
Pleural Rub
Pleural rub is a rough, grating sound produced by the pleurae, the lining of the lungs, rubbing against each other. This sound can be heard during both inhalation and exhalation.
Causes of abnormal lung sounds
Abnormal lung sounds are typically caused by anything that narrows or obstructs the airways, preventing smooth airflow and resulting in vibrations and various noises. The primary causes include:
– Mucus in the airways
– Swelling or inflammation of the airways
– Foreign objects or tumours blocking the airways
– Inflammation of the pleura
Specific diseases and conditions that can lead to abnormal lung sounds are –
– Respiratory infections such as bronchitis or croup, particularly common in young children with smaller airways
– Pneumonia
– Asthma
– Chronic obstructive pulmonary disease (COPD)
– Cystic fibrosis
– Allergies
– Anaphylaxis
– Tumours
– Foreign objects
– Pulmonary oedema
– Interstitial lung disease
– Heart failure
– Pulmonary embolism
When should an emergency care be called inn for abnormal breath sounds?
Go to the emergency room or call local emergency services if breathing difficulty comes on suddenly, is severe, or if someone stops breathing.
Cyanosis, a bluish colour of skin and mucous membranes due to lack of oxygen, can occur along with atypical breath sounds. Cyanosis involving the lips or the face is also a medical emergency.
A doctor will also look for the following signs of an emergency:
– Nasal flaring, which is an enlargement of the opening of the nostrils when breathing, that doctors see in babies and young children
– Abdominal breathing, which is the use of the abdominal muscles to assist breathing
– Accessory muscle use, which is the use of the neck and chest wall muscles to assist breathing
– Stridor, which indicates an upper airway obstruction
Diagnostic approach to abnormal lung sounds
– Chest X-ray
– CT scan
– Blood tests
– Culture of sputum
– Pulmonary function test
Treatment and management
– Antibiotic or antiviral therapy to treat infections
– Inhaled medications, like corticosteroids
– Epinephrine for severe allergic reactions
– Surgery to remove blockages
– Breathing treatments to facilitate open up the airways
– Hospital care in case of severe conditions when there is a serious infection or fluid buildup in the lungs or if the person has significant difficulty in breathing or there is severe airway blockage
– People with chronic conditions may need constant medication and breathing treatments.
– Individuals suffering from chronic asthma often need to carry a rescue inhaler and a doctor might prescribe medication to be taken all the time to clear congestion in the airways.
Ayurveda Understanding of Abnormal Breathing Sounds
Normal breath sounds have not been explained in Ayurveda. The absence of abnormal breathing patterns mentioned in ‘Pranavaha Sroto Dushti Lakshanas’ i.e. signs and symptoms of contamination of channels responsible for transportation of prana – vital life force – oxygen and nutrition can be considered as normal pattern of breathing and the sounds associated with such healthy breathing as normal breath sounds.
Though not direct, the references and key words describing the ‘abnormal breath sounds’ can be found mentioned in the below mentioned contexts –
– Shwasa – group of disorders marked with different patterns of abnormal breathing and difficulty in breathing
– Kasa – cough and its types
– Pranavaha Sroto Dushti – contamination or damage to the channels carrying oxygen / vital breath
They should be understood contextually and in sync with other symptoms mentioned in that disease or its type.
These sounds can be addressed when the abnormal breathing patterns are controlled by treating the above-mentioned conditions.
Such abnormal sounds manifesting along with abnormal patterns of breathing in other diseases can be treated by comprehensively treating those diseases causing abnormal patterns or sounds.
Related Reading – ‘Abnormal Breathing / Lung Sounds – Ayurveda Understanding’
