What is pneumothorax

A pneumothorax is the medical term for what is commonly known as a collapsed lung with the presence of air or gas in the pleural cavity (see Figures 2 to 4). A pneumothorax occurs when air leaks into the space between the lung and chest wall. This air pushes on the outside of your lung and makes it collapse. In most cases, only some of the lung collapses. It’s reasonably common and has many different causes.

A pneumothorax can be caused by a blunt or penetrating chest injury, certain medical procedures, or damage from underlying lung disease. Or it may occur for no obvious reason. Symptoms usually include sudden chest pain and shortness of breath. On some occasions, a collapsed lung can be a life-threatening event.

The clinical results are dependent on the degree of collapse of the lung on the affected side. If the pneumothorax is significant, it can cause a shift of the mediastinum and compromise hemodynamic stability.

• If you have a pneumothorax and you feel it is getting harder to breathe, call your local emergency number for an ambulance.

There are no direct figures on the incidence of pneumothorax. However, it is a common problem, frequently as a complication of trauma (often undiagnosed), and it also commonly occurs as a spontaneous occurrence and in patients with previous lung disease.

Treatment for a pneumothorax usually involves inserting a flexible tube or needle between the ribs to remove the excess air. However, a small pneumothorax may heal on its own.

The Lungs

The lungs (= lightweights, because they float) are paired cone-shaped, soft, spongy organs in the thoracic (chest) cavity (Figure 1). The lungs consist largely of air tubes and spaces. The balance of the lung tissue, its stroma, is a framework of connective tissue containing many elastic fibers. As a result, the lungs are light, soft, spongy, elastic organs that each weigh only about 0.6 kg (1.25 pounds). The elasticity of healthy lungs helps to reduce the effort of breathing. The lungs are separated from each other by the heart and other structures of the mediastinum, which divides the thoracic cavity into two anatomically distinct chambers. As a result, if trauma causes one lung to collapse, the other may remain expanded.

Each lung is enclosed and protected by a double-layered serous membrane called the pleural membrane or pleura. The superficial layer, called the parietal pleura, lines the wall of the thoracic cavity; the deep layer, the visceral pleura, covers the lungs themselves (Figures 2 and 3). Between the visceral and parietal pleurae is a small space, the pleural cavity, which contains a small amount of lubricating fluid secreted by the membranes. This pleural fluid reduces friction between the membranes, allowing them to slide easily over one another during breathing. Pleural fluid also causes the two membranes to adhere to one another just as a film of water causes two glass microscope slides to stick together, a phenomenon called surface tension. Separate pleural cavities surround the left and right lungs. The left and right lungs are situated in the left and right pleural cavities inside the thoracic cavity.

A lung will collapse if air enters the pleural cavity, a condition called pneumothorax. The air breaks the seal of pleural fluid that holds the lung to the thoracic wall, allowing the elastic lung to collapse like a deflating balloon.

Inflammation of the pleural membrane, called pleurisy or pleuritis, may in its early stages cause pain due to friction between the parietal and visceral layers of the pleura. If the inflammation persists, excess fluid accumulates in the pleural space, a condition known as pleural effusion.

Below the lungs, a thin, dome-shaped muscle called the diaphragm separates the chest from the abdomen. When you breathe, the diaphragm moves up and down, forcing air in and out of the lungs. The thoracic cage encloses the rest of the lungs.

Figure 1. Lungs anatomy

Figure 2. Lungs pleural cavity

Figure 3. Bronchial tree of the lungs

Types of pneumothorax

There are different types of pneumothorax:

Primary spontaneous pneumothorax

Primary spontaneous pneumothorax is the most common type of pneumothorax, has no known cause and develops in otherwise healthy people. It is thought to be caused by a tiny tear of an outer part of the lung. Primary spontaneous pneumothorax is more common in tall people and mainly affects healthy young adults without lung disease.

Secondary spontaneous pneumothorax

Secondary spontaneous pneumothorax develops as a complication of existing lung disease, such as chronic obstructive pulmonary disease (COPD), pneumonia, tuberculosis, sarcoidosis or cystic fibrosis. The lung disease weakens the edge of the lung in some way, making the lung more likely to tear and cause air to escape.

Catamenial pneumothorax

Catamenial pneumothorax: this is a pneumothorax occurring during the perimenstrual period ¹. “Perimenstrual period” encompasses the period of 72 – 96 hours before and after menstrual bleeding. The broadest definitions of catamenial pneumothorax describe it as pneumothorax occurring from 7 days before the start of monthly bleeding to 7 days after its completion ². The additional criteria include: characteristic pleural lesions, right-sided location of the pneumothorax, and concomitant endometriosis ³, ⁴. Concomitance of catamenial pneumothorax and endometriosis was described in a woman in the 8th week of pregnancy ⁵. Thoracic endometriosis is defined as the presence of ectopic endometrium within the chest, the symptoms of which appear during ovulation ⁶. Symptoms of pelvic endometriosis, secondary or primary infertility, and previous gynecological procedures ³ may suggest the diagnosis of catamenial pneumothorax in the course of endometriosis. A review of the treatment results of 110 patients with thoracic endometriosis revealed that pneumothorax occurred in 72% of the women, hemoptysis in 14%, pleural hematomas in 12%, and lung nodules in 2% ⁶. Pelvic endometriosis may precede the development of thoracic endometriosis by 5 years ⁷. Despite the fact that the most common manifestation of thoracic endometriosis is pneumothorax ⁶, in some cases of catamenial pneumothorax, endometrial character of the disease cannot be confirmed histologically ². Abnormal fenestrations in the tendinous part of the diaphragm can be observed during surgical procedures performed on patients suffering from catamenial pneumothorax concomitant with endometriosis. Furthermore, the patients’ pleurae feature spots and nodules which are endometrial implants. The lesions are most often located on the diaphragmatic pleura.

3% to 6% of spontaneous pneumothorax cases meet the definition of catamenial pneumothorax, constituting an indication for surgical treatment in 1/3 of the affected women. The mean age of onset is 32-35 years ⁸. The condition may develop as late as at 39 years of age ⁹. Catamenial pneumothorax is most often (85-95%) unilateral, occurring on the right side of the chest, but it may also occur on the left side or bilaterally ⁹.

The cause and subsequent development of catamenial pneumothorax is explained by the following theories: physiological, migrational, microembolic-metastatic, and the diaphragmatic theory of air “passage” (Table 1).

Table 1. Theories for the development of thoracic foci of endometriosis in the development of catamenial pneumothorax

Physiological	High concentration of prostaglandin F2 during menses may cause blood vessels and bronchioles to contract, which leads to alveolar rupture and development of pneumothorax.
Migrational	Endometrial cells may migrate from the uterus, through the fallopian tubes, into the lesser pelvis and further, into the area of the diaphragm. The cyclical proliferation and necrosis of endometrial cells may injure the diaphragm, enabling the cells to migrate further into the chest and the visceral pleura, which may lead to pulmonary alveolar injury and pneumothorax.
Microembolic-metastatic	Metastatic spread or pulmonary microembolization from endometrial cells through blood or lymph vessels. Necrosis of subpleural interstitial endometriotic foci leads to pneumothorax; foci located more centrally cause hemoptysis.
Diaphragmatic theory of air “passage”	Air passes through the uterus and fallopian tubes into the peritoneal cavity and, through diaphragmatic fenestrations, into the pleural cavity.

[Source ¹]

Catamenial pneumothorax is associated with the following findings: single or multiple fenestrations in the tendinous part of the diaphragm; red/brown spots or nodules located on the diaphragmatic or visceral pleura. Histopathological analysis of these nodules (spots) reveals glandular cells, endometrial stroma, and macrophages filled with hemosiderin, whereas immunohistochemical testing may demonstrate the presence of estrogen and progesterone receptors ¹⁰. These findings are observed if pneumothorax is accompanied by endometriosis, especially within the pelvis, as occurs in 30-51% of cases.

Traumatic pneumothorax

Traumatic pneumothorax is a type of pneumothorax is caused by an incident such as a car accident, broken ribs or a stab wound.

Iatrogenic pneumothorax

Iatrogenic pneumothorax is a pneumothorax that occurs as a result of mechanical ventilation, which causes an imbalance in the air pressure around the lungs.

Tension pneumothorax

Tension pneumothorax is a pneumothorax (of any type) that leads to the heart and lungs not working properly. It is a medical emergency.

Figure 4. Collapsed and normal lung

Figure 5. A large, right-sided pneumothorax has occurred from a rupture of a subpleural bleb (chest X-ray).

Progression of pneumothorax

Excluding that caused by chest trauma, pneumothorax arises due to rupture of alveoli, followed by rupture of the pleural lining of the lung. Provided this communication then seals itself off, air in the pleural space is gradually resorbed. If the communication between the pleural space and the airways remains open, a ‘bronchopleural fistula’ is created.

Rarely, the communication remains open, but the defect acts as a flap valve, allowing air into the pleural space on inspiration, but preventing it from escaping during expiration. Thus, air accumulates in the pleural space with each breath, compressing adjacent lung, and eventually compressing other structures in the chest, including the heart. This is called ‘tension pneumothorax’. Tension pneumothorax rarely occurs spontaneously.

Pneumothorax prognosis (outlook)

Tension pneumothorax is a potentially life-threatening condition, due to restriction of venous return, and respiratroy and cardiac shock. Otherwise, pneumothorax tends to slowly resolve, such that a pneumothorax causing 50% collapse of the lung will take 40 days to heal.

Pneumothorax complications

Many people who have had one pneumothorax can have another, usually within one to two years of the first. Air may sometimes continue to leak if the opening in the lung won’t close. Surgery may eventually be needed to close the air leak.

Pneumothorax causes

A pneumothorax can be caused by:

• Chest injury. Any blunt or penetrating injury to your chest can cause lung collapse. Some injuries may happen during physical assaults or car crashes, while others may inadvertently occur during medical procedures that involve the insertion of a needle into the chest.
• Lung disease. Damaged lung tissue is more likely to collapse. Lung damage can be caused by many types of underlying diseases, including chronic obstructive pulmonary disease (COPD), cystic fibrosis and pneumonia.
• Ruptured air blisters. Small air blisters (blebs) can develop on the top of your lung. These blebs sometimes burst — allowing air to leak into the space that surrounds the lungs.
• Mechanical ventilation. A severe type of pneumothorax can occur in people who need mechanical assistance to breathe. The ventilator can create an imbalance of air pressure within the chest. The lung may collapse completely.

Risk factors for a pneumothorax

Pneumothorax in those over 40 years of age is commonly seen in the background of emphysema or chronic bronchitis. Occasionally, asthma, and other lung disease can cause a pneumothorax.

In younger patients, pneumothorax may occur spontaneously or due to chest trauma. Spontaneous pneumothorax commonly occurs in tall, thin young men (sex ratio: 6:1), due to rupture of small subpleural ‘blebs’. Trauma such as a rib fracture, or penetrating chest wall injury, may also cause pneumothorax.

Risk factors for a pneumothorax include:

• Your sex. In general, men are far more likely to have a pneumothorax than are women.
• Smoking. The risk increases with the length of time and the number of cigarettes smoked, even without emphysema.
• Age. The type of pneumothorax caused by ruptured air blisters is most likely to occur in people between 20 and 40 years old, especially if the person is a very tall and underweight.
• Genetics. Certain types of pneumothorax appear to run in families.
• Lung disease. Having an underlying lung disease — especially chronic obstructive pulmonary disease (COPD) — makes a collapsed lung more likely.
• Mechanical ventilation. People who need mechanical ventilation to assist their breathing are at higher risk of pneumothorax.
• Previous pneumothorax. Anyone who has had one pneumothorax is at increased risk of another, usually within one to two years of the first.

Pneumothorax signs and symptoms

The presentation of patients with pneumothorax varies depending on the types of pneumothorax and ranges from completely asymptomatic to life-threatening respiratory distress:

• Spontaneous pneumothorax: No clinical signs or symptoms in primary spontaneous pneumothorax until a bleb ruptures and causes pneumothorax; typically, the result is acute onset of chest pain and shortness of breath, particularly with secondary spontaneous pneumothoraces
• Iatrogenic pneumothorax: Symptoms similar to those of spontaneous pneumothorax, depending on patient’s age, presence of underlying lung disease, and extent of pneumothorax
• Tension pneumothorax: Hypotension, hypoxia, chest pain, dyspnea
• Catamenial pneumothorax: Women aged 30-40 years with onset of symptoms within 48 hours of menstruation, right-sided pneumothorax, and recurrence
• Pneumomediastinum: Must be differentiated from spontaneous pneumothorax; patients may or may not have symptoms of chest pain, persistent cough, sore throat, dysphagia, shortness of breath, or nausea/vomiting.

The main symptoms of a pneumothorax are sudden chest pain and shortness of breath. But these symptoms can be caused by a variety of health problems, and some can be life-threatening. If your chest pain is severe or breathing becomes increasingly difficult, get immediate emergency care.

Spontaneous and iatrogenic pneumothorax

Until a bleb ruptures and causes pneumothorax, no clinical signs or symptoms are present in primary spontaneous pneumothorax. Young and otherwise healthy patients can tolerate the main physiologic consequences of a decrease in vital capacity and partial pressure of oxygen fairly well, with minimal changes in vital signs and symptoms, but those with underlying lung disease may have respiratory distress.

In one series, acute onset of chest pain and shortness of breath were present in all patients in one series; typically, both symptoms are present in 64-85% of patients. The chest pain is described as severe and/or stabbing, radiates to the ipsilateral (same side) shoulder and increases with inspiration (pleuritic).

In primary spontaneous pneumothorax, chest often improves over the first 24 hours, even without resolution of the underlying air accumulation. Well-tolerated primary spontaneous pneumothorax can take 12 weeks to resolve. In secondary spontaneous pneumothorax, the chest pain is more likely to persist with more significant clinical symptoms.

Shortness of breath/dyspnea in primary spontaneous pneumothorax is generally of sudden onset and tends to be more severe with secondary spontaneous pneumothorax because of decreased lung reserve. Anxiety, cough, and vague presenting symptoms (e.g, general malaise, fatigue) are less commonly observed. The most common underlying abnormality in secondary spontaneous pneumothorax is chronic obstructive pulmonary disease (COPD), and cystic fibrosis carries one of the highest associations, with more than 20% reporting spontaneous pneumothorax.

Despite descriptions of Valsalva maneuvers and increased intrathoracic pressures as inciting factors, spontaneous pneumothorax usually develops at rest. By definition, spontaneous pneumothorax is not associated with trauma or stress. Symptoms of iatrogenic pneumothorax are similar to those of a spontaneous pneumothorax and depend on the age of the patient, the presence of underlying lung disease, and the extent of the pneumothorax.

A history of previous pneumothorax is important, as recurrence is common, with rates reported between 15% and 40%. Up to 15% of recurrences can be on the contralateral (opposite) side. Secondary pneumothoraces are often more likely to recur, with cystic fibrosis carrying the highest recurrence rates at 68-90%. No study has shown that the number or size of blebs and bullae found in the lung can be used to predict recurrence.

Tension pneumothorax

Signs and symptoms of tension pneumothorax are usually more impressive than those seen with a simple pneumothorax, and clinical interpretation of these is crucial for diagnosing and treating the condition. Tension pneumothorax is classically characterized by hypotension (low blood pressure) and hypoxia (low blood oxygen). On examination, breath sounds are absent on the affected hemothorax and the trachea deviates away from the affected side. The thorax may also be hyperresonant; jugular venous distention and tachycardia may be present. If on mechanical ventilation, the airway pressure alarms are triggered.

Because of subtle presentations that do not always present with the classically described clinical findings of this condition or the complexity of the patient with critical illness or injury to describe a tension pneumothorax, actual case reports include descriptions of the diagnosis of the condition being missed or delayed.  Nevertheless, tension pneumothorax should always be a consideration when acute compromise occurs.

Symptoms of tension pneumothorax may include chest pain (90%), dyspnea (80%), anxiety, fatigue, or acute epigastric pain (a rare finding).

Catamenial pneumothorax

The symptoms of catamenial pneumothorax are typical of spontaneous pneumothorax, but the condition may also be asymptomatic.

Women aged 30-40 years who present with onset of symptoms within 48 hours of menstruation, right-sided pneumothorax, and recurrence raise suspicion for catamenial pneumothorax.

Pneumomediastinum

Pneumomediastinum must be differentiated from spontaneous pneumothorax. Patients may or may not have symptoms, as this is typically a well-tolerated disease, although mortality in cases of esophageal rupture is very high.

This condition usually occurs when intrathoracic pressures become elevated, such as with an exacerbation of asthma, coughing, vomiting, childbirth, seizures, and a Valsalva maneuver. In many patients who present with pneumomediastinum, it occurs as a result of endoscopy and small esophageal perforation.

In a retrospective review of cases presenting to an academic medical center, 67% of identified patients had chest pain; 42% had persistent cough; 25% had sore throat; and 8% had dysphagia, shortness of breath, or nausea/vomiting.

Other symptoms may include substernal chest pain, usually radiating to the neck, back, or shoulders and exacerbated by deep inspiration, coughing, or supine positioning; dyspnea; neck or jaw pain; dysphagia, dysphonia, and/or abdominal pain (unusual symptoms).

Traumatic mediastinum, although present in up to 6% of patients, does not portend serious injury ¹¹.

Pneumothorax diagnosis

A chest x-ray is the test of choice: small pneumothorax (less than 20% of hemithorax) may be difficult to see on chest x-ray; and a film taken during expiration it may help visualise it. In some cases, a computerized tomography (CT) scan may be needed to provide more-detailed images. CT scanners combine X-ray images taken from many different directions to produce cross-sectional views of internal structures.

Larger pneumothorax causes significant collapse of the lung, with shift of the trachea and mediastinum (heart and great vessels) away from the affected side.

Physical Examination

The presentation of a patient with pneumothorax may range from completely asymptomatic to life-threatening respiratory distress. Symptoms may include diaphoresis, splinting chest wall to relieve pleuritic pain, and cyanosis (in the case of tension pneumothorax). Findings on lung auscultation also vary depending on the extent of the pneumothorax. Affected patients may also reveal altered mental status changes, including decreased alertness and/or consciousness (a rare finding).

Respiratory findings may include the following:

• Respiratory distress (considered a universal finding) or respiratory arrest
• Tachypnea (or bradypnea as a preterminal event)
• Asymmetric lung expansion – A mediastinal and tracheal shift to the contralateral side can occur with a large tension pneumothorax
• Distant or absent breath sounds – Unilaterally decreased or absent lung sounds is a common finding, but decreased air entry may be absent even in an advanced state of the disease
• Lung sounds transmitted from the unaffected hemithorax are minimal with auscultation at the midaxillary line
• Hyperresonance on percussion – This is a rare finding and may be absent even in an advanced state of the disease
• Decreased tactile fremitus
• Adventitious lung sounds (crackles, wheeze; an ipsilateral finding)

Cardiovascular findings may include the following:

• Tachycardia – This is the most common finding. If the heart rate is faster than 135 beats/min, tension pneumothorax is likely
• Pulsus paradoxus
• Hypotension – This should be considered as an inconsistently present finding; although hypotension is typically considered a key sign of a tension pneumothorax, studies suggest that hypotension can be delayed until its appearance immediately precedes cardiovascular collapse
• Jugular venous distention – This is generally seen in tension pneumothorax, although it may be absent if hypotension is severe
• Cardiac apical displacement – This is a rare finding

Spontaneous and iatrogenic pneumothorax

Signs of spontaneous and iatrogenic pneumothorax are similar and depend on the underlying lung disease and extent of the pneumothorax. Tachycardia is the most common finding, and tachypnea and hypoxia may be present.

Tension pneumothorax

Although tension pneumothorax may be a difficult diagnosis to make and may present with considerable variability in signs, respiratory distress and chest pain are generally accepted as being universally present, and tachycardia and ipsilateral air entry on auscultation are also common findings. Sometimes, reliance on history alone may be warranted.

Findings may be affected by the volume status of the patient. In hypovolemic trauma patients with ongoing hemorrhage, the physical findings may lag behind the presentation of shock and cardiopulmonary collapse. Increased pulmonary artery pressures and decreased cardiac output or cardiac index are evidence of tension pneumothorax in patients with Swan-Ganz catheters.

When examining a patient for suspected tension pneumothorax, any clue may be helpful, as subtle thoracic size and thoracic mobility differences may be elicited by performing careful visual inspection along the line of the thorax. In a supine patient, the examiner should lower themselves to be on a level with the patient.

Tracheal deviation is an inconsistent finding. Although historic emphasis has been placed on tracheal deviation in the setting of tension pneumothorax, tracheal deviation is a relatively late finding caused by midline shift.

Abdominal distention may occur from increased pressure in the thoracic cavity producing caudal deviation of the diaphragm and from secondary pneumoperitoneum produced as air dissects across the diaphragm through the pores of Kohn.

If patients who are mechanically ventilated are difficult to ventilate during resuscitation, high peak airway pressures are clues to pneumothorax. A tension pneumothorax causes progressive difficulty with ventilation as the normal lung is compressed. On volume-control ventilation, this is indicated by marked increase in both peak and plateau pressures, with relatively preserved peak and plateau pressure difference. On pressure control ventilation, tension pneumothorax causes sudden drop in tidal volume. However, these observations are neither sensitive nor specific for making the diagnosis of pneumothorax or ruling out the possibility of pneumothorax.

The development of tension pneumothorax in patients who are ventilated will generally be of faster onset with immediate, progressive arterial and mixed venous oxyhemoglobin saturation decline and immediate decline in cardiac output. Cardiac arrest associated with asystole or pulseless electrical activity (PEA) may ultimately result. Occasionally, the tension pneumothorax may be tolerated and its diagnosis delayed for hours to days after the initial insult. The diagnosis may become evident only if the patient is receiving positive-pressure ventilation. Tension pneumothorax has been reported during surgery with both single- and double-lumen tubes.

Pneumomediastinum

As with pneumothorax, physical findings of pneumomediastinum may be variable, including absent signs in some patients. However, subcutaneous emphysema is the most consistent sign. Another sign, the Hamman sign—a precordial crunching noise synchronous with the heartbeat and often accentuated during expiration—has a variable rate of occurrence, with one series reporting 10%.

Catamenial pneumothorax

Bagan et al. point to the increase in the serum titer of the Ca125 antigen as a helpful marker of catamenial pneumothorax associated with endometriosis ¹². In accordance with the presented data, the value of Ca125 that indicates high probability of endometriosis is 76 U/ml. In a study published by Haga in 2013, an increase of the Ca125 antigen to 36.7 ±42.3 U/ml was considered significant ⁹. However, the marker is not specific, which limits its routine use.

Pneumothorax treatment

The goal in treating a pneumothorax is to relieve the pressure on your lung, allowing it to re-expand. Depending on the cause of the pneumothorax, a second goal may be to prevent recurrences. The methods for achieving these goals depend on the severity of the lung collapse and sometimes on your overall health.

Selection among various management options in pneumothorax requires an understanding of the natural history of pneumothorax, the risk of recurrent pneumothorax, and the benefits and limitations of treatment options. Observation without oxygen, administering supplemental oxygen, simple aspiration, chest tube placement, video-assisted thoracoscopic surgery (VATS), open thoracotomy, and pleurodesis are among these options.

• Small pneumothorax may not require treatment. If only a small portion of your lung is collapsed, your doctor may simply monitor your condition at 2-weekly intervals with a series of chest X-rays until the excess air is completely absorbed and your lung has re-expanded. Normally this takes a week or two. Supplemental oxygen may speed the absorption process.
• Larger, and tension, pneumothorax requires aspiration of air (needle passed between the ribs, into the pleural space), with insertion of an intercostal drainage tube soon after. This drainage tube ends with an underwater seal; thus, escaping air is seen as bubbles in the water, but air from the atmosphere can not go back in.
• Occasionally, the pneumothorax keeps bubbling after several days; this indicates the presence of bronchopleural fistula, and surgery may be needed. This involves either removal of the pleura, or adhesion of the two pleural layers to each other, by placing talc in the pleural space (talc pleurodesis).
• A tension pneumothorax should be treated with immediate decompression with a needle in the 2nd intercostal space (between the second and third rib at the front). This is then followed by a formal intercostal tube insertion as above.
• Treatment for catamenial pneumothorax involves hormonal therapy and surgical treatment (wedge lung resection, pleurectomy, chemical or mechanical pleurodesis, and diaphragm reconstruction – direct or using synthetic meshes) ¹. Video-assisted thoracoscopic surgery (VATS) is the access of choice in the treatment of pneumothorax. Thoracotomy is indicated almost exclusively in cases of recurrence after a previous procedure. The use of video-assisted mini-thoracotomy has been suggested if the procedure involves extensive lesions within the diaphragm ³. Most authors are in agreement in their recommendations to perform bullectomy, pleurectomy, or pleurodesis.

1. Marjański T, Sowa K, Czapla A, Rzyman W. Catamenial pneumothorax – a review of the literature. Kardiochirurgia i Torakochirurgia Polska = Polish Journal of Cardio-Thoracic Surgery. 2016;13(2):117-121. doi:10.5114/kitp.2016.61044. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4971265/[↩][↩][↩]
2. Rousset-Jablonski C, Alifano M, Plu-Bureau G, Camilleri-Broet S, Rousset P, Regnard JF, Gompel A. Catamenial pneumothorax endometriosis-related pneumothorax: clinical features and risk factors. Hum Repord. 2011;26:2322–2329. https://www.ncbi.nlm.nih.gov/pubmed/21685141[↩][↩]
3. Alifano M, Legras A, Rousset-Jablonski C, Bobbio A, Magdeleinat P, Damotte D, Roche N, Regnard JF. Pneumothorax recurrence after surgery in women: clinicopathologic characteristic and management. Ann Thorac Surg. 2011;92:322–326. https://www.ncbi.nlm.nih.gov/pubmed/21718864[↩][↩][↩]
4. Majak P, Langebrekke A, Hagen OM, Qviqstad E. Catamenial pneumothorax, clinical manifestations – a multidisciplinary challenge. Pneumonol Alergol Pol. 2011;79:347–350. https://www.ncbi.nlm.nih.gov/pubmed/21861259[↩]
5. Yoshioka H, Fukui T, Mori S, Usami N, Nagasaka T, Yokoi K. Catamenial pneumothorax in a pregnant patient. Jpn J Thorac Cardiovasc Surg. 2005;53:280–282. https://www.ncbi.nlm.nih.gov/pubmed/15952324[↩]
6. Channabasavaiah AD, Joseph JV. Thoracic endometriosis: revisiting the association between clinical presentation and thoracic pathology based on thoracoscopic findings in 110 patients. Medicine (Baltimore) 2010;89:183–188. https://www.ncbi.nlm.nih.gov/pubmed/20453605[↩][↩][↩]
7. Joseph J, Sahn SA. Thoracic endometriosis syndrome: new observation from an analysis of 110 cases. Am J Med. 1996;100:164–170. https://www.ncbi.nlm.nih.gov/pubmed/8629650[↩]
8. Attaran S, Bille A, Karenovics W, Lang-Lazdunski L. Videothoracoscopic repair of diaphragm and pleurectomy/abrasion in patients with catamenial pneumothorax: a 9-year experience. Chest. 2013;143:1066–1069. https://www.ncbi.nlm.nih.gov/pubmed/23117231[↩]
9. Haga T, Kurihara M, Kataoka H, Ebana H. Clinical-pathological findings of catamenial pneumothorax: comparison between recurrent cases and non-recurrent cases. Ann Thorac Cardiovasc Surg. 2014;20:202–206. https://www.jstage.jst.go.jp/article/atcs/20/3/20_oa.12.02227/_pdf/-char/en[↩][↩][↩]
10. Visouli AN, Darwiche K, Mpakas A, Zarogoulidis P, Papagiannis A, Tsakiridis K, Machairiotis N, Stylianaki A, Katsikogiannis N, Courcoutsakis N, Zarogoulidis K. Catamenial pneumothorax: a rare entity? Report of 5 cases and review of the literature. J Thorac Dis. 2012;4(Suppl 1):17–31. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3537379/[↩]
11. Rezende-Neto JB, Hoffmann J, Al Mahroos M, et al. Occult pneumomediastinum in blunt chest trauma: clinical significance. Injury. 2010 Jan. 41(1):40-3.[↩]
12. Bagan P, Berna P, Assouad J, Hupertan V, Le Pimpec Barthes F, Riquet M. Value of cancer antigen 125 for diagnosis of pleural endometriosis in females with recurrent pneumothorax. Eur Respir J. 2008;31:140–142. http://erj.ersjournals.com/content/31/1/140.long[↩]