Crepitation, subcutaneous [Subcutaneous crepitus, subcutaneous emphysema]
Crepitation, subcutaneous [Subcutaneous crepitus, subcutaneous emphysema]: Excerpt from Handbook of Signs & Symptoms (Third Edition)
When bubbles of air or other gases (such as carbon dioxide) are trapped in subcutaneous tissue, palpating or stroking the skin produces a crackling sound called subcutaneous crepitation or subcutaneous emphysema. The bubbles feel like small, unstable nodules and aren't painful, even though subcutaneous crepitation is commonly associated with painful disorders. Usually, the affected tissue is visibly edematous; this can lead to life-threatening airway occlusion if the edema affects the neck or upper chest.
The air or gas bubbles enter the tissues through open wounds from the action of anaerobic microorganisms or from traumatic or spontaneous rupture or perforation of pulmonary or GI organs.
History and physical examination
Because subcutaneous crepitation can indicate a life-threatening disorder, you'll need to perform a rapid initial evaluation and intervene if necessary. (See Managing subcutaneous crepitation, page 178.)
When the patient's condition permits, palpate the affected skin to evaluate the location and extent of subcutaneous crepitation and to obtain baseline information. Delineate the borders of the area of crepitus with a marker. Palpate the area frequently to determine if the subcutaneous crepitation is increasing. Ask the patient if he's experiencing pain or having difficulty breathing. If he's in pain, find out where the pain is located, how severe it is, and when it began. Ask about recent thoracic surgery, diagnostic tests, and respiratory therapy or a history of trauma or chronic pulmonary disease.
Medical causes
Gas gangrene.
Subcutaneous crepitation is the hallmark of gas gangrene, a rare but commonly fatal infection that's caused by anaerobic microorganisms. It's accompanied by local pain, swelling, and discoloration, with the formation of bullae and necrosis. The skin over the wound may rupture, revealing dark red or black necrotic muscle and producing foul-smelling, watery, or frothy discharge. Related findings include tachycardia, tachypnea, a moderate fever, cyanosis, and lassitude.
Orbital fracture.
An orbital fracture allows air from the nasal sinuses to escape into subcutaneous tissue, causing subcutaneous crepitation of the eyelid and orbit. The most common sign of this fracture is periorbital ecchymosis. Visual acuity is usually normal, although a swollen lid may prevent accurate testing. The patient has facial edema, diplopia, a hyphema and, occasionally, a dilated or unreactive pupil on the affected side. Extraocular movements may also be affected.
Pneumothorax.
Severe pneumothorax produces subcutaneous crepitation in the upper chest and neck. In many cases, the patient has chest pain that's unilateral, rarely localized initially, and increased on inspiration. Dyspnea, anxiety, restlessness, tachypnea, cyanosis, tachycardia, accessory muscle use, asymmetrical chest expansion, and a nonproductive cough can also occur. On the affected side, breath sounds are absent or decreased, hyperresonance or tympany may be heard, and decreased vocal fremitus may be present.
Rupture of the esophagus.
A ruptured esophagus usually produces subcutaneous crepitation in the neck, chest wall, or supraclavicular fossa, although this sign doesn't always occur. With a rupture of the cervical esophagus, the patient has excruciating pain in the neck or supraclavicular area, his neck is resistant to passive motion, and he has local tenderness, soft-tissue swelling, dysphagia, odynophagia, and orthostatic vertigo.
Life-threatening rupture of the intrathoracic esophagus can produce mediastinal emphysema confirmed by a positive Hamman's sign. The patient has severe retrosternal, epigastric, neck, or scapular pain and edema of the chest wall and neck. He may also display dyspnea, tachypnea, asymmetrical chest expansion, nasal flaring, cyanosis, diaphoresis, tachycardia, hypotension, dysphagia, and a fever.
Rupture of the trachea or major bronchus.
Rupture of the trachea or major bronchus is a life-threatening injury that produces abrupt subcutaneous crepitation of the neck and anterior chest wall. The patient has severe dyspnea with nasal flaring, tachycardia, accessory muscle use, hypotension, cyanosis, extreme anxiety and, possibly, hemoptysis and mediastinal emphysema, with a positive Hamman's sign.
Other causes
Diagnostic tests.
Endoscopic tests, such as bronchoscopy and upper GI tract endoscopy, can cause rupture or perforation of respiratory or GI organs, producing subcutaneous crepitation.
Respiratory treatments.
Mechanical ventilation and intermittent positive-pressure breathing can rupture alveoli, producing subcutaneous crepitation.
Thoracic surgery.
If air escapes into the tissue in the area of the incision, subcutaneous crepitation can occur.
Special considerations
Monitor the patient's vital signs frequently, especially respirations. Because excessive edema from subcutaneous crepitation in the neck and upper chest can cause airway obstruction, be alert for signs of respiratory distress such as dyspnea. Tell the patient that the affected tissues will eventually absorb the air or gas bubbles and the subcutaneous crepitation will decrease.
Pediatric pointers
Children may develop subcutaneous crepitation in the neck from ingestion of corrosive substances that perforate the esophagus.
Pictures
![Crepitation, subcutaneous [Subcutaneous crepitus, subcutaneous emphysema] - 4445.1.jpg](/bookimages/5/4445.1.jpg)
Book Source Details
- Book Title: Handbook of Signs & Symptoms (Third Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Handbook of Signs & Symptoms (Third Edition), Copyright © 2006 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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