Pneumothorax
A pneumothorax is an abnormal collection of air in the pleural space between the lung and the chest wall.[3] Symptoms typically include sudden onset of sharp, one-sided chest pain and shortness of breath.[2] In a minority of cases, a one-way valve is formed by an area of damaged tissue, and the amount of air in the space between chest wall and lungs increases; this is called a tension pneumothorax.[3] This can cause a steadily worsening oxygen shortage and low blood pressure. This leads to a type of shock called obstructive shock, which can be fatal unless reversed.[3] Very rarely, both lungs may be affected by a pneumothorax.[6] It is often called a "collapsed lung", although that term may also refer to atelectasis.[1]
"Collapsed lung" redirects here. For other uses, see Collapsed lung (disambiguation).Pneumothorax
Collapsed lung[1]
Chest pain, shortness of breath, tiredness[2]
Sudden[3]
Unknown, trauma[3]
COPD, tuberculosis, smog, smoking[4]
conservative, needle aspiration, chest tube, pleurodesis[3]
A primary spontaneous pneumothorax is one that occurs without an apparent cause and in the absence of significant lung disease.[3] A secondary spontaneous pneumothorax occurs in the presence of existing lung disease.[3][7] Smoking increases the risk of primary spontaneous pneumothorax, while the main underlying causes for secondary pneumothorax are COPD, asthma, and tuberculosis.[3][4] A traumatic pneumothorax can develop from physical trauma to the chest (including a blast injury) or from a complication of a healthcare intervention.[8][9]
Diagnosis of a pneumothorax by physical examination alone can be difficult (particularly in smaller pneumothoraces).[10] A chest X-ray, computed tomography (CT) scan, or ultrasound is usually used to confirm its presence.[5] Other conditions that can result in similar symptoms include a hemothorax (buildup of blood in the pleural space), pulmonary embolism, and heart attack.[2][11] A large bulla may look similar on a chest X-ray.[3]
A small spontaneous pneumothorax will typically resolve without treatment and requires only monitoring.[3] This approach may be most appropriate in people who have no underlying lung disease.[3] In a larger pneumothorax, or if there is shortness of breath, the air may be removed with a syringe or a chest tube connected to a one-way valve system.[3] Occasionally, surgery may be required if tube drainage is unsuccessful, or as a preventive measure, if there have been repeated episodes.[3] The surgical treatments usually involve pleurodesis (in which the layers of pleura are induced to stick together) or pleurectomy (the surgical removal of pleural membranes).[3] About 17–23 cases of pneumothorax occur per 100,000 people per year.[3][5] They are more common in men than women.[3]
Lateral inspired X-ray at the same time, more clearly showing the pneumothorax posteriorly in this case
Anteroposterior expired X-ray at the same time, more clearly showing the pneumothorax in this case
Chest X-ray showing a pneumothorax on the right (left in the image), where the absence of lung markings indicates that there is free air inside the chest
Chest X-ray showing the features of pneumothorax on the left side of the person (right in image)
Prevention[edit]
A preventative procedure (thoracotomy or thoracoscopy with pleurodesis) may be recommended after an episode of pneumothorax, with the intention to prevent recurrence. Evidence on the most effective treatment is still conflicting in some areas, and there is variation between treatments available in Europe and the US.[12] Not all episodes of pneumothorax require such interventions; the decision depends largely on estimation of the risk of recurrence. These procedures are often recommended after the occurrence of a second pneumothorax.[51] Surgery may need to be considered if someone has experienced pneumothorax on both sides ("bilateral"), sequential episodes that involve both sides, or if an episode was associated with pregnancy.[15]
Epidemiology[edit]
The annual age-adjusted incidence rate (AAIR) of PSP is thought to be three to six times as high in males as in females. Fishman[52][53] cites AAIR's of 7.4 and 1.2 cases per 100,000 person-years in males and females, respectively. Significantly above-average height is also associated with increased risk of PSP – in people who are at least 76 inches (1.93 meters) tall, the AAIR is about 200 cases per 100,000 person-years. Slim build also seems to increase the risk of PSP.[52]
The risk of contracting a first spontaneous pneumothorax is elevated among male and female smokers by factors of approximately 22 and 9, respectively, compared to matched non-smokers of the same sex.[54] Individuals who smoke at higher intensity are at higher risk, with a "greater-than-linear" effect; men who smoke 10 cigarettes per day have an approximate 20-fold increased risk over comparable non-smokers, while smokers consuming 20 cigarettes per day show an estimated 100-fold increase in risk.[52]
In secondary spontaneous pneumothorax, the estimated annual AAIR is 6.3 and 2.0 cases per 100,000 person-years for males and females,[21][55] respectively, with the risk of recurrence depending on the presence and severity of any underlying lung disease. Once a second episode has occurred, there is a high likelihood of subsequent further episodes.[12] The incidence in children has not been well studied,[19] but is estimated to be between 5 and 10 cases per 100,000 person-years.[56]
Death from pneumothorax is very uncommon (except in tension pneumothoraces). British statistics show an annual mortality rate of 1.26 and 0.62 deaths per million person-years in men and women, respectively.[15] A significantly increased risk of death is seen in older patients and in those with secondary pneumothoraces.[12]
History[edit]
An early description of traumatic pneumothorax secondary to rib fractures appears in Imperial Surgery by Turkish surgeon Şerafeddin Sabuncuoğlu (1385–1468), which also recommends a method of simple aspiration.[57]
Pneumothorax was described in 1803 by Jean Marc Gaspard Itard, a student of René Laennec, who provided an extensive description of the clinical picture in 1819.[58] While Itard and Laennec recognized that some cases were not due to tuberculosis (then the most common cause), the concept of spontaneous pneumothorax in the absence of tuberculosis (primary pneumothorax) was reintroduced by the Danish physician Hans Kjærgaard in 1932.[15][29][59] In 1941, the surgeons Tyson and Crandall introduced pleural abrasion for the treatment of pneumothorax.[15][60]
Prior to the advent of anti-tuberculous medications, pneumothoraces were intentionally caused by healthcare providers in people with tuberculosis in an effort to collapse a lobe, or entire lung, around a cavitating lesion. This was known as "resting the lung". It was introduced by the Italian surgeon Carlo Forlanini in 1888 and publicized by the American surgeon John Benjamin Murphy in the early 20th century (after discovering the same procedure independently). Murphy used the (then) recently discovered X-ray technology to create pneumothoraces of the correct size.[61]
Other animals[edit]
Non-human animals may experience both spontaneous and traumatic pneumothorax. Spontaneous pneumothorax is, as in humans, classified as primary or secondary, while traumatic pneumothorax is divided into open and closed (with or without chest wall damage).[63] The diagnosis may be apparent to the veterinary physician because the animal exhibits difficulty breathing in, or has shallow breathing. Pneumothoraces may arise from lung lesions (such as bullae) or from trauma to the chest wall.[64] In horses, traumatic pneumothorax may involve both hemithoraces, as the mediastinum is incomplete and there is a direct connection between the two halves of the chest.[65] Tension pneumothorax – the presence of which may be suspected due to rapidly deteriorating heart function, absent lung sounds throughout the thorax, and a barrel-shaped chest – is treated with an incision in the animal's chest to relieve the pressure, followed by insertion of a chest tube.[66] For spontaneous pneumothorax the use of CT for diagnosis has been described for dogs[67] and Kunekune pigs.[68]