Pneumomediastinum
Encyclopedia
Pneumomediastinum is a condition in which air is present in the mediastinum
. First described in 1819 by René Laennec
, the condition can result from physical trauma
or other situations that lead to air escaping from the lungs, airways or bowel into the chest cavity.
Pneumomediastinum is uncommon and occurs when air leaks into the mediastinum
. The diagnosis can be confirmed via chest X-ray
showing a radiolucent outline around the heart and mediastinum or via CT scanning of the thorax
.
It has also been associated with:
It can be induced to assist thoracoscopic surgery. It can be caused by a pulmonary barotrauma
resulting when a person moves to or from a higher pressure environment, such as when a SCUBA diver
, a free-diver
or an airplane passenger ascends or descends.
. It is often recognized on auscultation
by a "crunching" sound timed with the cardiac cycle (Hamman's crunch).
If the air is under pressure and compressing the heart, a needle may be inserted into the cavity, releasing the air.
Surgery may be needed to repair the hole in the trachea, esophagus or bowel.
If there is lung collapse, it is imperative the affected individual lies on the side of the collapse, although painful, this allows full inflation of the unaffected lung.
Mediastinum
The mediastinum is a non-delineated group of structures in the thorax, surrounded by loose connective tissue. It is the central compartment of the thoracic cavity...
. First described in 1819 by René Laennec
René Laennec
René-Théophile-Hyacinthe Laennec was a French physician. He invented the stethoscope in 1816, while working at the Hôpital Necker and pioneered its use in diagnosing various chest conditions....
, the condition can result from physical trauma
Physical trauma
Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...
or other situations that lead to air escaping from the lungs, airways or bowel into the chest cavity.
Presentation
Mediastinum
The mediastinum is a non-delineated group of structures in the thorax, surrounded by loose connective tissue. It is the central compartment of the thoracic cavity...
. The diagnosis can be confirmed via chest X-ray
Chest X-ray
In medicine, a chest radiograph, commonly called a chest X-ray , is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures...
showing a radiolucent outline around the heart and mediastinum or via CT scanning of the thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
.
Etiology
It is most commonly caused by:- Oesophageal rupture, for example in Boerhaave syndromeBoerhaave syndromeEsophageal rupture is rupture of the esophageal wall due to vomiting. 56% of esophageal perforations are iatrogenic, usually due to medical instrumentation such as an endoscopy or paraesophageal surgery...
- AsthmaAsthmaAsthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
or other conditions leading to alveolar rupture - Bowel rupture, where air in the abdominal cavity tracts up into the chest.
It has also been associated with:
- Mycoplasma pneumoniaeMycoplasma pneumoniaeMycoplasma pneumoniae is a very small bacterium in the class Mollicutes.It causes the disease mycoplasma pneumonia, a form of atypical bacterial pneumonia, and is related to cold agglutinin disease.-Cell wall/Treatment:...
pneumoniaPneumoniaPneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes... - obesityObesityObesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
It can be induced to assist thoracoscopic surgery. It can be caused by a pulmonary barotrauma
Barotrauma
Barotrauma is physical damage to body tissues caused by a difference in pressure between an air space inside or beside the body and the surrounding fluid...
resulting when a person moves to or from a higher pressure environment, such as when a SCUBA diver
Scuba diving
Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....
, a free-diver
Free-diving
Freediving is any of various aquatic activities that share the practice of breath-hold underwater diving. Examples include breathhold spear fishing, freedive photography, apnea competitions and, to a degree, snorkeling...
or an airplane passenger ascends or descends.
Signs and Symptoms
The main symptom is usually severe central chest pain. Other symptoms include laboured breathing, voice distortion (as with helium) and subcutaneous emphysemaSubcutaneous emphysema
Subcutaneous emphysema, sometimes abbreviated SCE or SE and also called tissue emphysema, or Sub Q air, occurs when gas or air is present in the subcutaneous layer of the skin. Subcutaneous refers to the tissue beneath the cutis of the skin, and emphysema refers to trapped air...
. It is often recognized on auscultation
Auscultation
Auscultation is the term for listening to the internal sounds of the body, usually using a stethoscope...
by a "crunching" sound timed with the cardiac cycle (Hamman's crunch).
Treatment
The tissues in the mediastinum will slowly resorb the air in the cavity so most pneumomediastinums are treated conservatively. Breathing high flow oxygen will increase the absorption of the air.If the air is under pressure and compressing the heart, a needle may be inserted into the cavity, releasing the air.
Surgery may be needed to repair the hole in the trachea, esophagus or bowel.
If there is lung collapse, it is imperative the affected individual lies on the side of the collapse, although painful, this allows full inflation of the unaffected lung.