Using a stethoscope, a doctor can listen to the sounds of the lungs. One type of sound that can indicate a problem is called bibasilar crackles.

The sounds of the lungs can provide clues that help a doctor to diagnose an underlying condition.

In this article, learn about the conditions that cause bibasilar crackles. We also describe how a doctor diagnoses and treats them.

What are bibasilar crackles?

Doctor using stethoscope to listen to patient's breathing
Bibasilar crackles are a sound that can occur in the lungs.

Bibasilar crackles are abnormal sounds from the base of the lungs. They indicate that something is interfering with airflow.

Two issues often cause bibasilar crackles. One is the accumulation of mucus or fluid in the lungs. Another is a failure of parts of the lungs to inflate properly.

The crackles themselves are not a disease, but they can be a sign of an illness or infection.

The crackles sound like brief popping when a person breathes. Some people describe the sound as similar to wood burning in a fireplace.

Bibasilar crackles are more common during inhalation, but they can occur when a person exhales.

Doctors classify the crackles as fine or coarse, depending on their volume, pitch, and duration.

For example, fine crackles are often soft and high-pitched. Coarse crackles are usually louder and low-pitched, with a wet or bubbling sound.

Bibasilar crackles may occur with additional symptoms, depending on the underlying cause. Possible accompanying symptoms include:

  • trouble breathing
  • coughing
  • fever
  • swelling in the feet or lower legs
  • fatigue


Many conditions can cause bibasilar crackles, and they are usually based in the heart or lungs. Below are some potential causes of bibasilar crackles.


Pneumonia is an infection in the lungs, which can result from a virus, bacteria, or fungus.

The infection can cause shortness of breath, fatigue, and coughing, as well as bibasilar crackles. In some cases, pneumonia can be life-threatening.

According to the United States Centers for Disease Control and Prevention, pneumonia is the leading infectious cause of death in children under age 5 worldwide.

Heart failure

Heart failure occurs when the heart is too weak to pump blood efficiently to the rest of the body.

If the heart is not working correctly, the blood does not exit the lungs as quickly as it should. This can cause fluid to build up, and it can pool in the lungs.

Heart failure can affect both children and adults. Heart failure affects approximately 5.7 million people in the U.S.

Beyond bibasilar crackles, symptoms may include swelling in the abdomen, coughing, and shortness of breath.


Bronchitis involves inflammation of the bronchi, which are the tubes leading to the lungs. Bronchitis can be acute or chronic.

Acute bronchitis often results from a virus, and it typically lasts for 3–10 days.

Exposure to lung irritants, such as tobacco, is often the cause of chronic bronchitis.

Some symptoms of bronchitis include coughing, chest congestion, and fatigue.

Pulmonary edema

An infection or trauma may cause pulmonary edema
Infection and trauma are some causes of pulmonary edema.

Pulmonary edema involves a buildup of fluid in the alveoli, which are small air sacs in the lungs.

Possible causes of pulmonary edema include:

  • heart damage or dysfunction
  • damage to the pulmonary capillaries
  • trauma to the chest
  • infection
  • inhalation of a toxic substance

Pulmonary edema can result from altitude sickness, which occurs when a person unaccustomed to altitudes ascends to 2,500 meters or higher.

In addition to bibasilar crackles, symptoms of pulmonary edema include coughing, trouble breathing, blue-tinged lips, and spitting up pink, frothy mucus.

Pulmonary fibrosis

Pulmonary fibrosis is a type of interstitial lung disease characterized by scarring of the lungs.

In most cases, the underlying cause is unknown.

However, pulmonary fibrosis can result from exposure to hazardous materials, such as radiation, animal droppings, and asbestos.

Symptoms include a dry cough, shortness of breath, and unexplained weight loss.


A doctor can diagnose bibasilar crackles using lung auscultation, which involves listening to lungs sounds with a stethoscope.

Several characteristics can help a doctor to determine the cause of the crackles, including whether they occur when a person inhales or exhales.

For example, crackles that occur late in the inspiratory phase (when a person inhales) may indicate heart failure or pneumonia.

A doctor may also ask for:

  • chest X-rays
  • a sputum sample to test for infection
  • blood tests to test for infection
  • an echocardiogram to check the function of the heart
  • an arterial blood gas analysis to check the blood’s acidity, oxygen, and carbon dioxide levels


Oxygen therapy may help to treat bibasilar crackles.
Oxygen therapy may help treat bibasilar crackles.

Treatment for bibasilar crackles will depend on the underlying cause. The crackles may fade or disappear after treatment.

However, if the cause is a chronic condition, the crackles may occur on and off for an extended period.

Below are some treatments for common causes of bibasilar crackles.


A doctor may prescribe diuretics for a person with heart failure. Diuretics are medications developed to reduce levels of fluid in the lungs.

A person may require antibiotics if the crackles have resulted from bacterial pneumonia or bronchitis.

Doctors may also prescribe steroids to decrease inflammation in the lungs.

Oxygen therapy

Many causes of bibasilar crackles lead to shortness of breath. Oxygen therapy can help to make breathing easier.

Lifestyle changes

In some instances, crackles result from chronic lung disease.

Making certain lifestyle changes, such as stopping smoking, may help to treat the underlying condition and prevent long-term complications.

When to see a doctor

Anyone with symptoms of bibasilar crackles should speak to a doctor as soon as possible.

The crackles are an abnormal sound, and they usually indicate that an underlying condition requires treatment.

Bibasilar crackles can result from a severe lung problem. Prompt diagnosis and treatment may help to prevent long-term complications.

Anyone who experiences bibasilar crackles and shortness of breath, chest pain, or blood-tinged mucus should seek immediate medical attention.