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Crepitus

What Is It, Causes, How It’s Assessed, and More

Author: Ashley Mauldin, MSN, APRN, FNP-BC

Editors: Ahaana Singh, Józia McGowan, DO

Illustrator: Jillian Dunbar

Copyeditor: David G. Walker


What is crepitus from the lungs?

Crepitus in the lungs refers to the sound and sensation associated with subcutaneous emphysema, a condition in which air is trapped under the skin. It is characterized by the palpable or audible popping, crackling, grating, or crunching sensation that can occur when air is pushed through the soft tissue in the chest. Crepitus is not a disease but rather a symptom of an underlying condition.

Crepitus can also occur in the joints in the body, like the knees, shoulders, elbows, and neck. It usually results when surfaces in a joint rub together from long-term inflammatory conditions, like rheumatoid arthritis.

What does crepitus from the lungs sound like?

Subcutaneous crepitus from the lungs usually sounds like crackling, clicking, or popping sounds.

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What causes crepitus from the lungs?

The causes of subcutaneous crepitus usually involve conditions that cause subcutaneous emphysema (i.e., air present in the tissues in the skin), like a pneumothorax ( i.e., collapsed lung) or a rupture or tear in the airway or esophagus (i.e., the tube that transports food from the mouth to the stomach). 

Crepitus can also be heard in individuals who are on mechanical ventilation, a machine that helps with breathing; this would occur if air is present in the mediastinum (i.e., area of the chest that contains the heart) after escaping from the lungs. It can also sometimes be heard in individuals who have experienced chest trauma, like a penetrating wound or blunt trauma

When air leaks out of the lungs, like with a collapsed lung, the air can collect in the subcutaneous tissues of the neck and chest, causing subcutaneous emphysema. Crepitus occurs when pressure is applied to the affected area, causing the trapped air to produce popping sounds or a crackling sound.

How do you assess crepitus from the lungs?

Subcutaneous crepitus is assessed by a physical examination. The healthcare provider will palpate, or apply pressure to the affected area, and a crackling sound can sometimes be heard or felt.

The diagnosis and treatment of crepitus is usually aimed at determining the underlying cause of subcutaneous emphysema. Healthcare providers may be able to diagnose subcutaneous emphysema and the cause through a physical examination; however, they may also need to perform more diagnostic tests, like a computed tomography, or CT, scan and a magnetic resonance imaging, or MRI, scan. Treatment usually involves correcting the underlying condition.

What are the most important facts to know about crepitus from lungs?

Crepitus from the lungs refers to the palpable or audible popping, crackling, grating, or crunching sensation that can occur when air is pushed through the soft tissue in the chest. The causes of crepitus in the lungs usually involve conditions that cause subcutaneous emphysema (i.e., air present in the tissues in the skin), like a pneumothorax (i.e., collapsed lung) or a rupture or tear in the airway or esophagus (i.e., the tube that transports food from the mouth to the stomach). Crepitus occurs when pressure is applied to the affected area, causing the trapped air to produce popping sounds or a crackling sound. Crepitus can be assessed through a physical examination. The healthcare provider will palpate, or apply pressure to the affected area, and a crackling sound can sometimes be heard or felt. The diagnosis and treatment of crepitus is usually aimed at determining the underlying cause.

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Related links

Respiratory system anatomy and physiology
Pneumothorax
Rheumatoid arthritis

Resources for research and reference

Crepitus (joint popping): Joint pain. (n.d.). In Aurora Health Care. Retrieved May 06, 2021, from https://www.aurorahealthcare.org/services/orthopedics/conditions/crepitus

Kacmarek, R. M., & Egan, D. F. (2017). Egan's Fundamentals of respiratory care. Elsevier. 

Kukuruza, K., & Aboeed, A. (July 16, 2021). Subcutaneous Emphysema. In StatPearls [Internet]. Treasure Island (FL): Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK542192/

Subcutaneous emphysema. (2021). In MedlinePlus. Retrieved May 06, 2021, from https://medlineplus.gov/ency/article/003286.htm