Pneumothorax

In medicine(pulmonology), a pneumothorax or collapsed lung is a medical emergencycaused by the collapse of the lung within the chest cavity. It can result from a penetrating chest wound or barotraumato the lungs. Additionally, it can develop spontaneously in predisposed individuals (tall, slim individuals who smoke; young males have a higher risk than females).

Signs and symptoms

Sudden shortness of breath, cyanosis(turning blue) and pain felt in the chest and/or back are the main symptoms. In penetrating chest wounds, the sound of air flowing through the puncture hole may indicate pneumothorax. The flopping sound of the punctured lung is occasionally heard.

If untreated, the hypoxiawill lead to loss of consciousness and coma. In addition, shifting of the mediastinumtowards the site of the injury can obstruct the aortaand other large blood vessels, depriving distal tissues of blood. Untreated, a severe pneumothorax can lead to death within several minutes.

Spontaneous pneumothoraces are reported in young people with a tall stature. As men are generally taller than women, there is a preponderance among males. The reason for this association, while unknown, is hypothesized to be the presence of subtle abnormalities in connective tissue.

Pneumothorax can also occur as part of medical procedures, such as the insertion of a central venous catheter(an intravenouscatheter) in the subclavian vein(vena subclavia) or jugular vein(vena jugularis). While rare, it is considered a serious complication and needs immediate treatment. Other causes include mechanical ventilation, emphysemaand rarely other lung diseases (pneumonia).

Diagnosis

The absence of audible breath sounds through a stethoscopecan indicate that the lung is not unfolded in the pleural cavity. This accompanied by hyperresonance(higher pitched sounds than normal) to percussion of the chest wall is suggestive of the diagnosis. If the signs and symptoms are doubtful, an X-rayof the chest can be performed, but in severe hypoxia, emergency treatment has to be administered first.

In a supinechest X-ray the deep sulcus sign is diagnostic^{[{{fullurl:Template:FULLPAGENAME}}#endnote_Kong]}, which is characterized by a low lateral costophrenic angle on the affected side.^{[{{fullurl:Template:FULLPAGENAME}}#endnote_Gordon]} Stated differently, the place where riband diaphragmmeet appears lower on an X-ray with a deep sulcus sign and suggests the diagnosis of pneumothorax.

Pathophysiology

The lungsare located inside the chest cavity, which is a hollow space. Air is drawn into the lungs by the diaphragm(a powerful abdominalmuscle). The pleural cavityis the region between the chest wall and the lungs. If air enters the pleural cavity, either from the outside (open pneumothorax) or from the lung (closed pneumothorax), the lung collapses and it becomes mechanically impossible for the injured person to breathe, even with a patent airway. If a piece of tissue forms a one-way valve that allows air to enter the pleural cavity from the lung but not to escape, overpressure can build up with every breath; this is known as tension pneumothorax. It may lead to severe shortness of breath as well as circulatory collapse, both life-threatening conditions. This condition requires urgent intervention.

First Aid

Chest wound

Penetrating wounds require immediate coverage with pressure bandages made air-tight with petroleum jelly or clean plastic sheeting. The sterile inside of plastic bandage packaging is good for this purpose; however any airtight material, even the cellophane of a cigarette pack, can be used. A small opening, known as a flutter valve, needs to be left open, so the air can escape while the lung reinflates. Any patient with a penetrating chest wound must be closely watched at all times and may develop a tension pneumothorax or other immediately life-threatening respiratory emergency at any moment. They cannot be left alone.

Blast injury or spontaneous

If the air in the pleural cavity is due to a tear in the lung tissue (in the case of a blast injury or tension pneumothorax), it needs to be released. A thin needle can be used for this purpose, to relieve the pressure and allow the lung to reinflate.

Emergency services

Emergency servicescan generally provide oxygen therapyand positive pressure ventilating during transport to a hospital. Intubationmay be required, even of a conscious patient, if the situation deteriorates. Advanced medical care and immediate evacuationare strongly indicated.

In case of mountain evacuation (MEDEVAC), altitude can affect the patient. If the patient becomes short of breath while being transported, returning to the former height is important. Even a helicopter might have to alter its altitude multiple times before it can land, and reach an ambulance.

Clinical treatment

Small Pneumothoraces require no treatment other than repeat observation via Chest X-rays.

Larger Pneumothoraces may require tube thoracostomy, also known as chest tubeplacement. A tube is inserted into the chest wall outside the lung and air is extracted using a simple one way valve or vacuum and a water valve device, depending on severity. This allows the lung to re-expand within the chest cavity. The pneumothorax is followed up with repeated X-rays. If the air pocket has become small enough, the vacuum drain can be clamped temporarily or removed.

In case of penetrating wounds, these require attention, but generally only after the airway has been secured and a chest draininserted. Supportive therapy may include mechanical ventilation.

Recurrent pneumothorax may require further corrective and/or preventative measures such as pleurodesis. If the pneumothorax is the result of bullae, then bullaectomy(the removal or stapling of bullae or other faults in the lung) is preferred. Pleurodesis is the injection of a chemical irritant that triggers an inflammatoryreaction, leading to adhesion of the lung to the parietal pleura. Substances used for pleurodesis include talc, bloodand bleomycin.

History

Jean Itard, a student of Rene Laennec, first recognised pneumothorax in 1803, and Laennec himself described the full clinical picture in 1819^{[{{fullurl:Template:FULLPAGENAME}}#endnote_Laennec]}.

References

1. ^ Kong A. The deep sulcus sign. Radiology. 2003 Aug;228(2):415-6. PMID 12893899Full Text
2. ^ Gordon R. The deep sulcus sign. Radiology. 1980 Jul;136(1):25-7. PMID 7384513
3. ^  Laennec RTH. Traite de l'auscultation mediate et des maladies des poumons et du coeur. Part II. Paris, 1819.

See also

• Emergency medicine
• Tension pneumothorax

External links

• An X-ray with deep sulcus sign- learningradiology.com
• Pneumothorax.org - Pneumothorax news, information and forumsde:Pneumothorax

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It uses material from the http://en.wikipedia.org/wiki/Pneumothorax Wikipedia article Pneumothorax.