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Pneumothorax is a collection of air or gas in the chest or pleural space that causes part or all of a lung to collapse.


Normally, the pressure in the lungs is greater than the pressure in the pleural space surrounding the lungs. However, if air enters the pleural space, the pressure in the pleura then becomes greater than the pressure in the lungs, causing the lung to collapse partially or completely. Pneumothorax can be either spontaneous or due to trauma.
If a pneumothorax occurs suddenly or for no known reason, it is called a spontaneous pneumothorax. This condition most often strikes tall, thin men between the ages of 20 to 40. In addition, people with lung disorders, such as emphysema, cystic fibrosis, and tuberculosis, are at higher risk for spontaneous pneumothorax. Traumatic pneumothorax is the result of accident or injury due to medical procedures performed to the chest cavity, such as thoracentesis or mechanical ventilation. Tension pneumothorax is a serious and potentially life-threatening condition that may be caused by traumatic injury, chronic lung disease, or as a complication of a medical procedure. In this type of pneumothorax, air enters the chest cavity, but cannot escape. This greatly increased pressure in the pleural space causes the lung to collapse completely, compresses the heart, and pushes the heart and associated blood vessels toward the unaffected side.

Causes and symptoms

The symptoms of pneumothrax depend on how much air enters the chest, how much the lung collapses, and the extent of lung disease. Symptoms include the following, according to the cause of the pneumothorax:
  • Spontaneous pneumothorax. Simple spontaneous pneumothorax is caused by a rupture of a small air sac or fluid-filled sac in the lung. It may be related to activity in otherwise healthy people or may occur during scuba diving or flying at high altitudes. Complicated spontaneous pneumothorax, also generally caused by rupture of a small sac in the lung, occurs in people with lung diseases. The symptoms of complicated spontaneous pneumothorax tend to be worse than those of simple pneumothorax, due to the underlying lung disease. Spontaneous pneumothorax is characterized by dull, sharp, or stabbing chest pain that begins suddenly and becomes worse with deep breathing or coughing. Other symptoms are shortness of breath, rapid breathing, abnormal breathing movement (that is, little chest wall movement when breathing), and cough.
  • Tension pneumothorax. Following trauma, air may enter the chest cavity. A penetrating chest wound allows outside air to enter the chest, causing the lung to collapse. Certain medical procedures performed in the chest cavity, such as thoracentesis, also may cause a lung to collapse. Tension pneumothorax may be the immediate result of an injury; the delayed complication of a hidden injury, such as a fractured rib, that punctures the lung; or the result of lung damage from asthma, chronic bronchitis, or emphysema. Symptoms of tension pneumothorax tend to be severe with sudden onset. There is marked anxiety, distended neck veins, weak pulse, decreased breath sounds on the affected side, and a shift of the mediastinum to the opposite side.


To diagnose pneumothorax, it is necessary for the health care provider to listen to the chest (auscultation) during a physical examination. By using a stethoscope, the physician may note that one part of the chest does not transmit the normal sounds of breathing. A chest x ray will show the air pocket and the collapsed lung. An electrocardiogram (ECG) will be performed to record the electrical impulses that control the heart's activity. Blood samples may be taken to check for the level of arterial blood gases.


A small pneumothorax may resolve on its own, but most require medical treatment. The object of treatment is to remove air from the chest and allow the lung to re-expand. This is done by inserting a needle and syringe (if the pneumothorax is small) or chest tube through the chest wall. This allows the air to escape without allowing any air back in. The lung will then re-expand itself within a few days. Surgery may be needed for repeat occurrences.


Most people recover fully from spontaneous pneumothorax. Up to half of patients with spontaneous pneumothorax experience recurrence. Recovery from a collapsed lung generally takes one to two weeks. Tension pneumothorax can cause death rapidly due to inadequate heart output or insufficient blood oxygen (hypoxemia), and must be treated as a medical emergency.


Preventive measures for a non-injury related pneumothorax include stopping smoking and seeking medical attention for respiratory problems. If the pneumothorax occurs in both lungs or more than once in the same lung, surgery may be needed to prevent it from occurring again.

Key terms

Electrocardiagram — A test that provides a typical record of normal heart action.
Mediastinum — The space between the right and left lung.
Pleural — Pleural refers to the pleura or membrane that enfolds the lungs.
Thoracentesis — Also called a pleural fluid tap, this procedure involves aspiration of fluid from the pleural space using a long, thin needle inserted between the ribs.



American Association for Respiratory Care. 11030 Ables Lane, Dallas, Texas 75229. (972) 243-2272.
American Lung Association. 1740 Broadway, New York, NY 10019. (800) 586-4872.


"Spontaneous Pneumothorax."
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.


accumulation of air or gas in the pleural cavity, resulting in collapse of the lung on the affected side. The condition may occur spontaneously (spontaneous pneumothorax), as in the course of a pulmonary disease, or it may follow perforating trauma to the chest wall or lung parenchyma (traumatic or open pneumothorax).
Spontaneous Pneumothorax. This condition occurs when there is an opening on the surface of the lung allowing leakage of air from the airways or lung parenchyma into the pleural cavity. Most often it occurs when an emphysematous bulla or other weakened area on the lung ruptures. Normally the pleural cavity is an airtight compartment with a negative pressure. When air enters the pleural cavity the lung collapses, producing shortness of breath and mediastinal shift toward the unaffected side (see also mediastinal shift). Other signs and symptoms are a sudden sharp chest pain, fall in blood pressure, weak and rapid pulse, and cessation of normal respiratory movements on the affected side of the chest.

A small spontaneous pneumothorax may require no specific treatment beyond rest and administration of oxygen for relief of dyspnea. Chest x-rays should be obtained. The patient usually is more comfortable if allowed to sit up. A larger spontaneous pneumothorax may require a more aggressive approach such as aspiration to allow for reexpansion of the lung. If air continues to leak from the defect in the lung surface a continuous closed-drainage apparatus is set up (see chest tube). As soon as the lung lesion heals and the lung is reexpanded, the patient is allowed to resume usual daily activities. Guidelines for the treatment of spontaneous pneumothorax have been published by the American College of Chest Physicians and are available on their web site at
Tension pneumothorax. This is a particularly dangerous form that occurs when air escapes into the pleural cavity from a bronchus but cannot regain entry into the bronchus. As a result, continuously increasing air pressure in the pleural cavity causes progressive collapse of the lung tissue. Emergency aspiration of air from the pleural cavity is necessary in this disorder. If untreated, increased pressure within the pleural cavity will cause lung collapse and mediastinal shift.
Pneumothorax. Air within the pleural cavity has entered some of the space normally occupied by the lung, thus preventing its expansion and causing partial collapse.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


The presence of free air or gas in the pleural cavity.
[G. pneuma, air, + thorax]
Farlex Partner Medical Dictionary © Farlex 2012


(no͞o′mō-thôr′ăks′, nyo͞o′-)
Accumulation of air or gas in the pleural cavity, occurring as a result of disease or injury, or sometimes induced to collapse the lung in the treatment of tuberculosis and other lung diseases.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


Lung collapse Pulmology The presence of air in the pleural space, which may be 1º–seen in tall, thin, young ♂, characterized by subpleural apical blebs, 2º–asthma, COPD, PCP, trauma, TB, iatrogenic–due to thoracentesis, subclavian line placement, PEEP, bronchoscopy Clinical Pleural pain, dyspnea, ↓ breath sounds, percussion hyperresonance, ↓ tactile fremitus Management Small blebs may heal spontaneously, larger pneumothoraces require chest tube drainage, pleurodesis. See Spontaneous pneumothorax.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


The presence of air or gas in the pleural cavity.
[G. pneuma, air, + thorax]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


(noo?mo-thor'aks?, nu? ) (-thor'a-sez?) plural.pneumothoracesplural.pneumothoraxes [ pneum- + thorax]
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A collection of air or gas in the pleural cavity. The gas enters following a perforation through the chest wall, e.g., due to traumatic or iatrogenic injury, or the pleura, e.g., from the rupture of an emphysematous bleb or superficial lung abscess. Some tall, slender young men and women suffer repeated episodes of spontaneous pneumothorax. illustration;


The onset is sudden, usually with a severe sharp pain in the side of the chest, and dyspnea. The physical signs are those of a distended unilateral chest, increased resonance, decrease in or absence of breath sounds, and, if fluid is present, a splashing sound on succussion (shaking) of the patient. Patients often report chest pain is worsened by coughing, deep breathing, or movement.


Chest x-rays confirm the diagnosis, revealing air in the pleural space, often identified as a line seen outlining a partially collapsed lung. A shift of the mediastinum toward one side of the chest or the other may be seen in tension pneumothorax. See: tension pneumothorax


Treatment varies according to type and amount of lung collapse. Traumatic or iatrogenic pneumothorax requires chest tube insertion to closed (water-sealed) chest drainage for lung re-expansion. Surgical repair also may be required. Spontaneous pneumothorax may be treated conservatively with bedrest if there is no sign of increased pleural pressure, less than 15% lung collapse, no dyspnea or other indication of physiological compromise. If the patient's condition worsens or if more than 15% of the lung is collapsed, a thoracostomy tube may be placed anteriorly in the second intercostal space and attached to a Heimlich flutter valve or chest-drainage unit. If fluid is present in the pleural space, a thoracostomy tube is placed in the fourth, fifth, or sixth intercostal space more posteriorly to drain it.

Patient care

The patient's vital signs, chest expansion, oximetry and/or blood gases are monitored and oxygen administered to prevent hypoxia. The purpose and process for placing a chest tube are explained to the patient to allay anxiety and foster cooperation with the procedure. After the surgeon prepares and drapes the patient in sterile fashion, and administers local anesthesia, a small incision is made. A thoracostomy tube is attached to a water-sealed drainage device. The patient is placed in the semi-Fowler position to promote drainage, comfort, and ease of breathing. Vital signs and ventilatory status are monitored. Once the tube is placed, deep breathing (incentive spirometry) and coughing are encouraged (at least hourly) to promote lung expansion, with prescribed analgesics provided to control pain and discomfort (due in part to the tube itself). Ambulation is encouraged to facilitate full inspiration and enhance lung expansion. The thoracostomy tube site is kept sealed, generally by using a purse-string suture and occlusive dressing. Care is taken to avoid tension on the tubing, and all connections also are sealed to avoid air leaks. If the tube is accidentally dislodged, an occlusive (petroleum gauze) dressing is placed over the opening immediately to prevent lung collapse. When chest x-ray demonstrates adequate lung re-expansion that remains stable without suction, the thoracostomy tube is carefully removed, and the incision is covered with an occlusive dressing. The importance of follow-up examination, x-ray, and any needed care is explained prior to discharge. Patients who smoke are urged to stop smoking and exercise is increased gradually as determined by follow-up evaluation.

artificial pneumothorax

An intentionally and artificially induced pneumothorax, used to facilitate transcutaneous mediastinal biopsy and, infrequently, to treat pulmonary tuberculosis and pneumonia. Pneumothorax allows the diseased lung to rest temporarily. The lung collapses when the air enters the pleural space.

Scattered adhesions may afford only a partial collapse. Effusion may occur in about one third of the cases. Hazards include pain, infection, and respiratory distress.

catamenial pneumothorax

Pneumothorax that occurs during menses and resulting from endometrial implants in the chest, e.g. along the diaphragm or in the pleural space.

extrapleural pneumothorax

The formation of a pneumothorax by introducing air into the space between the pleura and the inside of the rib cage.

occult pneumothorax

A pneumothorax that is not detected by physical examination of the patient or by plain x-rays but is identified instead by other means, usually a CT scan of the chest and abdomen. The condition may be life-threatening.

open pneumothorax

A pneumothorax in which the pleural cavity is exposed to the atmosphere through an open wound in the chest wall.

spontaneous pneumothorax

The spontaneous entrance of air into the pleural cavity. The pressure may collapse the lung and displace the mediastinum away from the side of the lesion.


Although some patients with pneumothorax have few symptoms, most people who come to clinical attention report the sudden onset of left- or right-sided chest pain, often accompanied by shortness of breath. Breath sounds may be absent on the affected side, or the lung percussion note on that side may reveal increased resonance.

tension pneumothorax

A type of pneumothorax in which air can enter the pleural space but cannot escape via the route of entry. This leads to increased pressure in the pleural space, resulting in lung collapse. The increase in pressure also compresses the heart and vena cavae, which impairs circulation.

Patient care

The patient is assessed for evidence of respiratory failure or the need for immediate intervention. The development of tension pneumothorax is a medical emergency; if it is not promptly relieved, the patient will experience inadequate cardiac output and hypoxemia (and may die). To prevent rapid decompensation, a large-bore needle is inserted emergently into the pleural space at the second intercostal space, mid-clavicular line (needle decompression, needle thoracotomy). This temporizing procedure must be followed by thoracostomy tube placement and water-sealed chest drainage unit.

Medical Dictionary, © 2009 Farlex and Partners


The presence of air in the normally potential space between the two layers of the PLEURA (the pleural cavity). This may occur spontaneously from the rupture of a CONGENITAL bleb on the inner layer, or may result from air access from the outside through a wound. Pneumothorax causes the collapse of the lung on the same side. In minor cases there is recovery without treatment, but the air may have to be withdrawn through a tube.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005


Presence of free air or gas in pleural cavity.
[G. pneuma, air, + thorax]
Medical Dictionary for the Dental Professions © Farlex 2012