Why Does My Chest Crackle When I Breathe

Have you had a cough recently, and noticed any unusual noise coming from your chest while breathing? If yes, you may be experiencing chest crackles.

Crackling in the chest can be caused by a number of conditions that affect the lungs or heart (because both organs are closely linked). It usually occurs when there is a buildup of fluid, mucus, or pus in your lungs that makes it difficult for your lungs to work properly. 

There are many reasons why this may be happening, and you can learn more about these here. 

Understanding lung sounds 

Lung sounds, commonly called breath sounds, are the normal sounds that are produced by the lungs during breathing.¹ These lung or breath sounds can be heard through the chest using a stethoscope.^2,3 So, lung sounds are normal. As long as you are breathing or doing anything that requires the use of your lungs, then you should have lung or breath sounds. 

Types of lung sounds

The breath sounds are classified as normal and adventitious. They are identified and classified according to the location where the breath sounds are heard during a medical exam. 

Normal lung sounds could either be bronchial, vesicular, or bronchiovesicular. 

• Bronchial lung sounds that are loud, harsh, and high in pitch are typically heard over the trachea or at the top right area of the lung. They are most commonly heard when you breathe out or expire. If these sounds are heard in other parts of the lung, they are considered to be abnormal.¹ To check for this sound, your doctor will most likely place the stethoscope at the top of your chest, close to your throat. 
• Vesicular lung sounds, in contrast, are predominantly produced when you are breathing in and are usually heard in the bottom areas of the lungs. They are soft and low-pitched and may sometimes produce rustling sounds.² They are easily located by placing the stethoscope on the back. 
• Bronchiovesicular lung sounds can be said to be the middlemen because they are heard when you are breathing in and out.1 Bronchiovesicular sounds also have a mid-range pitch and intensity, so they are neither very high nor very low. Your doctor can locate them by listening to the middle area of your chest.¹ 

These three types are normal lung sounds which your doctor expects to hear during a medical exam. The other category of lung sounds, adventitious lung sounds, refers to the sounds that are sometimes heard in addition to the ones mentioned above and may be indicative of a lung condition. Crackles, stridor, pleural rubs, and wheezes are the most common types of adventitious lung sounds. 

• Crackles are short, high-pitched, intermittent sounds that are produced when you breathe in. The sound can be similar to that of a velcro strap being opened.¹ Crackles are usually produced when the air you breathe in passes through fluid, pus, or mucus. Crackles are classified as either coarse or fine, depending on how they sound. The sound quality of coarse crackles is low-pitched and moist; it can be heard in pulmonary oedema and bronchitis. Fine crackles, which sound like hair rubbing against the ear, can be heard in congestive heart failure and pulmonary fibrosis.⁴
• Wheezes produce a high-pitched, continuous musical sound. This happens when air passes through an obstructed, narrow airway.⁴ The sonorous wheeze, also known as rhonchi, is a deep, low-pitched rumbling or coarse sound produced when air has to move through mucus and other respiratory secretions in the lungs and tracheal passages. During expiration, it is commonly heard in the lungs. This is common in people with asthma,⁵ emphysema, and chronic bronchitis.¹
• Stridor is a continuous, high-pitched crowing sound that is mostly heard during inspiration. The most common cause of this sound is a partial obstruction of the larynx or trachea. It is common to hear stridor when there is a foreign body obstructing your airways or if you have a croup. In stridor, the movement of air through the upper airway is very difficult, so the sound is usually loudest in the frontal part of the neck. 
• Plural rub is a sound produced when inflamed lung surfaces rub against one another during breathing, speaking, or coughing. The sound is described as a harsh grating or creaking. Tuberculosis and pneumonia are two possible causes. During both inspiration and expiration, it is best heard in the lower part of the chest.⁴ 

Common causes

As we have identified, normal lung sounds are expected, and if they are absent when breathing, then there may be a problem with your lungs. However, the second group - adventitious lung sounds are not normal, and they may be a sign of any number of lung problems. 

These are some conditions that may cause adventitious lung sounds: 

• Acute or chronic bronchitis⁶ 
• Asthma⁵
• Bronchiectasis⁷  
• Congestive heart failure
• Emphysema
• Interstitial lung disease⁸
• Foreign body obstruction of the airway
• Pneumonia⁸
• Pulmonary oedema
• Tracheobronchitis 

Chest crackle when breathing

Crackling sounds in the chest are associated with several conditions like asthma, chronic obstructive pulmonary disease (COPD), interstitial lung disease, bronchiectasis, and pneumonia.⁸ 

Causes

Crackles can occur as a result of heart problems that cause blood flow to back up between your lungs and heart.⁹ Some of the common conditions include: 

Pneumonia

Pneumonia is an infection that causes the air sacs in one or both lungs to become inflamed. The air sacs may become clogged with fluid or pus (purulent material), producing phlegm or pus cough, fever, chills, and difficulty breathing. Pneumonia can be caused by a variety of organisms, including bacteria, viruses, and fungi.¹¹ 

The severity of pneumonia can range from mild to life-threatening. It is especially dangerous for infants and young children, people over the age of 65, and those with health issues or weakened immune systems.¹² In pneumonia, the air has to pass through the fluid that has built up in the lungs, causing difficulty in the process, which often produces crackles in the chest. 

Some symptoms of pneumonia include 

• Chest pain when breathing 
• Coughing that produces phlegm
• Tiredness 
• Fever, sweating, and chills
• Body temperature that is lower than normal (in adults older than age 65 and people with weak immune systems)
• Vomiting, nausea, or diarrhoea
• Breathing difficulty

Heart disease

Heart diseases are fairly common, and they are the leading cause of death in the United States for men, women, and people of most racial and ethnic groups.14 In the United States, one person dies from cardiovascular disease every 34 seconds.^13,14

In many heart diseases, especially congestive heart failure, fluid builds up in the lungs (pulmonary oedema) and in and around the airways can occur as a result of heart failure. This can result in shortness of breath, coughing, wheezing, and crackles, which are symptoms of asthma.

Some symptoms of heart disease may include: 

• Chest pain or discomfort
• Dizziness
• Fainting (syncope) or near fainting
• Fluttering in the chest
• Lightheadedness
• Racing heartbeat (tachycardia)
• Shortness of breath
• Slow heartbeat (bradycardia)

Pulmonary fibrosis

Pulmonary fibrosis is a lung disease which occurs when the lung tissue is damaged and scarred. It could result from damage to the lungs from infections or other conditions. The stiffening and thickening of the tissue make it more difficult for your lungs to function properly. As pulmonary fibrosis worsens, it may become increasingly harder to breathe, which sometimes produces crackles.¹⁵

Some symptoms of pulmonary fibrosis include: 

• Breathing difficulty (dyspnea)
• Dry cough
• Tiredness
• Unexplained weight loss
• Muscle and joint pain
• Widening and rounding of the finger or toe tips (clubbing)

Cystic fibrosis

Cystic fibrosis is an inherited disease that causes sticky mucus to accumulate in the lungs and digestive tract. This leads to lung infections and digestive issues.¹⁶

The accumulation of sticky mucus in the lungs can cause breathing difficulties and raises the risk of lung infection. The lungs may eventually stop working properly.

Mucus also clogs the pancreas (the digestive organ), preventing enzymes from reaching food in the gut and aiding digestion.¹⁶

Symptoms of Cystic Fibrosis:

The symptoms of cystic fibrosis often start in childhood and could be different, depending on the child who has it, but they usually get worse as a person gets older, causing more damage to the lungs and digestive system. Other symptoms include: 

• repeated chest infections
• wheezing, coughing, shortness of breath, and airway damage (bronchiectasis)
• having difficulty gaining weight and developing yellowing of the skin and the whites of the eyes (jaundice)
• diarrhoea, constipation, or foul-smelling faeces

Symptoms

The symptoms of crackles in the chest would usually occur as symptoms of the condition that causes the crackles. These are some common symptoms of chest crackles: 

• coughing with trouble breathing 
• fever 
• extreme and frequent tiredness 

Diagnosis

Crackles in the chest can be detected by your doctor through auscultation of your chest with a stethoscope. The crackles may be heard as you inhale or exhale, this information is helpful for your doctor to determine what is causing the crackles.²

In addition to the chest auscultation, your doctor may also require: 

• an x-ray of the chest 
• an echocardiogram 
• a sputum test
• a blood test 

Complications 

Crackles in the chest indicate that something is preventing your lungs from passing air properly. If this is not checked immediately, the problem will get worse and may lead to more severe outcomes. 

Treatment and preventions

Listen to your body and observe and record any changes that you notice in your breathing. Coughs may come once in a while, but when they last longer than a few days and lead to changes in your breathing, you should have your chest checked. 

Medications may be prescribed by your doctor, to address whatever the cause of the crackles is, especially to reduce the fluid in the lungs or loosen the mucus up, so it can be passed out of the lungs. 

Also, many lung conditions develop from damage to the lungs, caused by smoking. So, if you smoke, you may want to consider quitting. 

When to seek medical attention

Crackles in the chest are abnormal and are usually an indication of a more serious problem, which could be a lung disease or a heart problem. Once you observe any sounds that are unusual, please see your general practitioner immediately. Remember that early detection and treatment increase the chances of survival and can prevent complications.

Summary

Lung sounds are normal and expected, but sometimes, your lungs may have trouble taking air in and out, and this may result in chest crackles. Chest crackles are often a symptom of a more serious problem with your lungs, so once you observe any sounds that are weird, please see your doctor.