Treatment of secondary spontaneous pneumothorax in adults

INTRODUCTION — Pneumothorax (gas in the pleural space) can be a life-threatening condition that needs prompt assessment.

The management of secondary spontaneous pneumothorax (SSP; ie, that which presents as a complication of underlying lung disease) is discussed in this topic review. The epidemiology, etiology, clinical presentation, and diagnosis of pneumothorax, and the management of primary spontaneous pneumothorax (PSP; ie, that which occurs in the absence of lung disease) are discussed separately. (See "Clinical presentation and diagnosis of pneumothorax" and "Pneumothorax in adults: Epidemiology and etiology" and "Treatment of primary spontaneous pneumothorax in adults".)

DEFINITION (SECONDARY PNEUMOTHORAX) — A spontaneous pneumothorax is considered one that presents in the absence of an external factor. The management strategies of primary spontaneous pneumothorax (PSP; that which presents in the absence of clinical lung disease) and secondary spontaneous pneumothorax (SSP; that which presents as a complication of underlying lung disease) (table 1) differ in their threshold to perform a chest tube thoracostomy and to perform a definitive procedure to prevent recurrence. Thus, following the radiographic identification of pneumothorax, clinicians should quickly estimate the size, assess the degree of symptomatology, and attempt to classify the pneumothorax as primary (that without underlying lung disorder), secondary (that due to underlying lung disorder), or other (trauma, iatrogenic) so that appropriate therapy can be initiated. The diagnosis and classification of pneumothorax and treatment of primary pneumothorax are discussed separately. (See "Pneumothorax in adults: Epidemiology and etiology" and "Clinical presentation and diagnosis of pneumothorax" and "Treatment of primary spontaneous pneumothorax in adults".)

INITIAL MANAGEMENT OF FIRST EVENT — Most patients with secondary spontaneous pneumothorax (SSP) are treated with supplemental oxygen and removal of air from the pleural space, typically by chest tube thoracostomy. Patients also typically undergo a definitive procedure to prevent recurrence during the same hospitalization. Our approach expands upon that outlined in published clinical consensus statements and guidelines from the American College of Chest Physicians (ACCP; 2001), the British Thoracic Society (2010), the European Respiratory Society (2015), the Japanese Association for Chest Surgery (2014), and others [1-5]. While some experts use a symptom-driven approach and others prefer a size-driven approach, we prefer one that incorporates size and symptoms.

Assessment of size and stability

Definition of size limits — There is no consensus statement regarding size to guide clinicians when managing patients with SSP. Estimation of size is usually only performed on chest radiography (and less commonly chest computed tomography [CT]); ultrasonography cannot reliably quantify pneumothorax size and is generally imperfect. For pneumothorax identified using ultrasound, we believe that chest radiography should be done to estimate the size, although practice may vary considerably and no guidelines are available to facilitate this decision. Our suggested cutoff from the pleural line to the apex of <2 cm (small pneumothorax) and ≥2 cm (large pneumothorax) is based upon our experience and used as a general guideline only. Further details regarding the assessment of size are provided separately. (See "Clinical presentation and diagnosis of pneumothorax", section on 'Pneumothorax size'.)

Definition of stability — The definition of stability suggested by the ACCP [2] comprises patients with all of the following:

●Respiratory rate <24 breaths per minute

●Heart rate <120 and >60 beats per minute

●Normal blood pressure (not defined)

●Room air oxygen saturation >90 percent

●Ability to speak in whole sentences

Management strategy

Unstable patients — Instability due to pneumothorax (including tension pneumothorax) is more common in patients with SSP than primary spontaneous pneumothorax (PSP). Patients who are unstable due to SSP should undergo chest tube thoracostomy or alternatively, needle decompression of the pleural space, if chest tube decompression is delayed. (See "Clinical presentation and diagnosis of pneumothorax", section on 'Pneumothorax appearance and types' and "Initial evaluation and management of blunt thoracic trauma in adults", section on 'Pneumothorax' and "Approach to shock in the adult trauma patient", section on 'Tension pneumothorax'.)

Stable patients — Most clinically stable patients (see 'Definition of stability' above) with an SSP should be treated with catheter or chest tube thoracostomy based upon the rationale that compared with PSP, patients with SSP have underlying lung disease that increases the likelihood of failure of aspiration, a prolonged air leak, and the development of tension [1,6].

Small (<2 cm at apex) — In patients with a small SSP (<2 cm from the pleural line to the chest wall at the apex (see 'Definition of size limits' above)) who have significant symptoms, a catheter or tube thoracostomy is preferred, and the patient should be hospitalized. (See 'Tube or catheter thoracostomy' below.)

However, exceptions may exist. For example, for patients with a small SSP or patients who are asymptomatic or have minimal symptoms, treating with observation or supplemental oxygen and/or aspiration is appropriate. The threshold to admit the patients should be low. Progression of symptoms or an enlarging pneumothorax is an indication for pleural drainage. The administration and period of observation and follow up for those on oxygen and observation or aspiration are discussed below. (See 'Aspiration' below and "Treatment of primary spontaneous pneumothorax in adults", section on 'Observation with or without oxygen'.)

Large (≥2 cm at apex) — For patients with a large SSP (≥2 cm from the pleural line to the chest wall at the apex (see 'Definition of size limits' above)), prompt drainage by tube or catheter thoracostomy and subsequent hospitalization are often indicated because of the risk of respiratory impairment and need for definitive intervention [7]. (See 'Tube or catheter thoracostomy' below.)

General supportive care — Patients with SSP are treated with supplemental oxygen, if needed, and the underlying reason for pneumothorax is treated. Patients are generally admitted.

Supplemental oxygen — Supplemental oxygen is discussed in the section below. (See 'Oxygen and observation' below.)

Treatment of the underlying lung disease — Patients with SSP have pneumothorax as a complication of their underlying lung disease which may need to be treated together with the pneumothorax. For example, pneumothorax may precipitate or be a complication of a chronic obstructive pulmonary disease (COPD) exacerbation or asthma attack, necessitating therapy with nebulized bronchodilators and corticosteroids. (See "COPD exacerbations: Management" and "Acute exacerbations of asthma in adults: Home and office management".)

Therapies to avoid — Patients with SSP are more likely than those with PSP to need concomitant therapies; however, some may worsen the pneumothorax and should be avoided. As examples:

●Noninvasive ventilation (NIV) – In general, NIV should be avoided, when feasible (eg, mild to moderate non-life-threatening obstructive sleep apnea) since it is plausible the application of positive pressure increases the risk of a prolonged air leak and progression to tension. In addition, a few anecdotal cases exist to support the development of pneumothorax in those receiving NIV, although no reports have been published demonstrating progression in those with established pneumothorax. Despite this risk, cautious use may be warranted in select circumstances (eg, in patients with respiratory failure who prefer to avoid mechanical ventilation who have a thoracostomy tube in place). (See "Noninvasive ventilation in adults with acute respiratory failure: Benefits and contraindications".)

●High-flow nasal oxygen via nasal cannulae (HFNC) – For similar reasons, HFNC is best avoided due to the small amount of positive pressure that is delivered to the airway with this mode of oxygen delivery. (See "Heated and humidified high-flow nasal oxygen in adults: Practical considerations and potential applications".)

●Chest physical therapy – Based upon our experience we suggest individualizing airway clearance measures in patients with pneumothorax based upon the risk of progression. For example, on one hand the risk of progression may be higher in those on positive expiratory pressure (PEP)/oscillating PEP and manual chest percussion while on the other hand, the risk of mucus plugging from withholding therapy may also contribute to the progression. Factors to take into consideration include the type of physical therapy, size of the pneumothorax, and the presence of a catheter/chest tube. These recommendations are typically most pertinent to those with cystic fibrosis. (See "Cystic fibrosis: Overview of the treatment of lung disease", section on 'Chest physiotherapy'.)

Nebulized therapy does not need to be held while pneumothorax is being treated.

Disposition — Almost all patients with SSP should be hospitalized, because the underlying lung disease increases the risk for an adverse outcome (eg, respiratory failure, cardiovascular collapse, recurrent event) [1,4,8]. Exceptions are rare but might include stable patients with minimal symptoms and a small SSP (<2 cm), who may be observed in the outpatient setting if follow-up and access to health care are good [4]. (See 'Small (<2 cm at apex)' above.)

INITIAL MANAGEMENT OF RECURRENT EVENT — While patients with secondary spontaneous pneumothorax (SSP) should have a definitive intervention after their first event to prevent recurrence, some patients are ineligible or unwilling to undergo a definitive procedure. Should these patients recur, a chest tube or catheter thoracostomy should be placed to manage recurrence and the option of a definitive procedure should be revisited. (See 'Tube or catheter thoracostomy' below.)

INITIAL THERAPEUTIC OPTIONS — The majority of patients with secondary spontaneous pneumothorax (SSP) undergo tube or catheter thoracostomy placement. Less commonly, for minimally symptomatic small pneumothoraces, aspiration or oxygen and observation may be appropriate. (See 'Initial management of first event' above.)

Tube or catheter thoracostomy — Chest tube or catheter (eg, pigtail catheter) thoracostomy is generally preferred over simple aspiration for drainage of air in patients with SSP because it is more likely to be successful [1,9]. In one trial, 28 patients with SSP were randomly assigned to receive tube thoracostomy and 33 patients to simple aspiration [10]. The tube thoracostomy group was more likely to have their pleural air completely evacuated than the needle aspiration group (93 versus 67 percent). The lower success rate of pleural aspiration in SSP than in primary spontaneous pneumothorax (PSP) may be due to a higher rate of persistent air leakage (ie, larger leaks) [11].

Chest tube thoracostomy refers to the insertion of a standard chest tube, while catheter thoracostomy refers to the insertion of a catheter, which is usually small, more pliable, and therefore less painful (eg, pigtail catheter). The details regarding insertion and management is similar to that described for patients with primary spontaneous pneumothorax (PSP), with some minor differences which are discussed in the section below. (See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children" and "Treatment of primary spontaneous pneumothorax in adults", section on 'Unstable patients'.)

Ambulatory drainage device — A multicenter randomized trial examined the use of devices involving one-way flutter valve to allow home management of SSP in 41 patients. However use of ambulatory device had a high early treatment failure rate (46 percent) and was not recommended [12].

Size — For most clinically stable patients with SSP, we prefer to use small-bore catheters (≤14 French [Fr]) or small-bore chest tubes (≤22 Fr) rather than large-bore chest tubes based upon ease of insertion, patient comfort, and evidence that supports equal efficacy [13-15]. However, some patients may benefit from the insertion of large-bore chest tubes only (24 to 28 Fr), including the following:

●Patients with large air leaks – Patients with large air leaks may need a large-bore chest tube to provide enough drainage capacity; alternatively, they may benefit from a second small-bore catheter.

●Patients with concomitant empyema or hemothorax – Patients with concomitant empyema or hemothorax are thought to benefit from large-bore tubes for drainage since small-bore catheters are at increased risk of blockage from clot or debris. In the case of hemothorax, the purpose of a chest tube is also to monitor the rate of blood loss, making a large-bore tube desirable.

●Patients who are unstable with tension pneumothorax – In patients with tension pneumothorax, a large-bore tube is often placed based upon the likelihood of a large or persistent air leak.

●Patients with barotrauma from mechanical ventilation – Many experts prefer large-bore chest tubes in patients with barotrauma, since the air leak is likely to be large and may lead to tension pneumothorax, although the risk is unquantified. However, practice varies greatly and is dependent upon availability of expertise and institutional practices. A retrospective study of 62 mechanically ventilated patients reported lower success rates with small-bore chest tubes when the pneumothorax was thought to be due to barotrauma than when the pneumothorax was due to iatrogenic causes (43 versus 88 percent) [16]. Management of barotrauma during mechanical ventilation is discussed separately. (See "Diagnosis, management, and prevention of pulmonary barotrauma during invasive mechanical ventilation in adults".)

Immediate follow-up — The general principles of immediate follow-up of patients with SSP who have chest tube or catheter thoracostomy including the indications for the application of suction (most patients are initially placed on water seal) are similar to that of patients with PSP. However, the prevalence of prolonged (persistent) air leak (PAL) is more common. Thus, most patients remain hospitalized with the chest tube in place until a definitive procedure is performed to prevent recurrence. (See "Treatment of primary spontaneous pneumothorax in adults", section on 'Follow-up thoracostomy management (one to five days)'.)

After a thoracostomy is placed we suggest the following:

●Sealed air leak – Patients with SSP in whom the air leak has sealed should proceed directly to having a preventive measure. However, if patients choose to decline immediate intervention, they can be discharged with an ambulatory valve (eg, Heimlich valve (picture 1)), provided that there is no concurrent fluid that continues to drain, and return for a definitive procedure as soon as possible at a later date. As a lesser option, patients can have their chest tube/catheter removed in the same way as patients with PSP, understanding the risk of recurrence is highest in the first 30 days after pneumothorax. (See "Treatment of primary spontaneous pneumothorax in adults", section on 'Sealed air leak'.)

●Prolonged (persistent) air leak – Compared with those who have PSP, PALs due to ruptured subpleural bullae or cysts (eg, chronic obstructive pulmonary disease [COPD], pneumocystis pneumonia) are more common and tend to persist longer in patients with SSP [17,18]. These patients require definitive measures to seal the defect and prevent future recurrence. In most patients, video-assisted or medical thoracoscopy (VATS) is preferred, although nonsurgical pleurodesis (with chemical sclerosants) or prolonged thoracostomy drainage are options in patients who are not good candidates for or are unwilling to undergo surgery. Increasingly endobronchial valves are used as an alternative option. Blood patch has been used but the evidence remains limited. Further details regarding definitive management are provided separately. (See "Pneumothorax: Definitive management and prevention of recurrence", section on 'Definitive measures' and "Alveolopleural fistula and prolonged air leak in adults", section on 'Bronchoscopic interventions'.)

Others — Oxygen with observation and aspiration are therapies that are only occasionally used in patients with SSP.

Oxygen and observation — Supplemental oxygen (for a minimum of six hours) and observation is an option for clinically stable patients who have a first episode of SSP that is small (<2 cm from the pleural line to the chest wall at the level of the apex) and who are asymptomatic or minimally symptomatic or for patients in whom options are limited. (See 'Small (<2 cm at apex)' above.)

Unlike patients with PSP, hypoxemia is common in patients with SSP. Supplemental oxygen is administered to virtually all patients with SSP to treat hypoxemia and facilitate absorption of air from the pleural space [1]. The protocol is similar to that described for patients with PSP except the threshold for admission and placement of a thoracostomy tube is lower. However, in contrast with patients who have PSP in whom high flow oxygen can be administered liberally, the fraction of inspired oxygen (FiO₂) should be increased cautiously in patients with SSP who have or are at risk for oxygen-induced hypercapnia (eg, moderate to severe COPD) [19]. Similar to patients with PSP, high flow oxygen delivered via nasal cannulae (HFNC) should be avoided, when feasible, since HFNC delivers a small amount of positive pressure to the airway that could potentially worsen the pneumothorax and perpetuate the air leak. Titration of oxygen in patients with hypercapnia is discussed separately. (See "The evaluation, diagnosis, and treatment of the adult patient with acute hypercapnic respiratory failure", section on 'Titration of oxygen' and "Heated and humidified high-flow nasal oxygen in adults: Practical considerations and potential applications" and "Treatment of primary spontaneous pneumothorax in adults", section on 'Observation with or without oxygen'.)

This strategy is not generally suitable for those with a recurrent event but can be rarely considered in those with severe underlying lung disease and a small loculated pneumothorax in whom other options are limited.

Aspiration — Aspiration is an option in stable patients with a small SSP (<2 cm from the pleural line to the chest wall at the level of the apex) who have mild or no symptoms or for those in whom options are limited. (See 'Small (<2 cm at apex)' above.)

This option is usually limited to centers with expertise. The procedure for aspirating air is similar to that described in patients with PSP except the threshold for admission following aspiration should be lower since the likelihood of failing aspiration is higher [10,11]. (See 'Tube or catheter thoracostomy' above and "Treatment of primary spontaneous pneumothorax in adults", section on 'Aspiration'.)

PREVENTING RECURRENCE AND FOLLOW-UP — In contrast with patients who have primary spontaneous pneumothorax (PSP), most patients with a first episode of secondary spontaneous pneumothorax (SSP) should undergo a definitive intervention during the same hospitalization (eg, within three to five days), to prevent recurrence (algorithm 1). This approach is based upon the high recurrence rate (generally >50 percent), the higher likelihood of a life-threatening event, and the high efficacy of pleurodesis in this population. Individual exceptions may apply to patients with very small loculated pneumothoraces (eg, patients with cystic fibrosis [4]) or patients who decline pleurodesis. In most cases, video-assisted thoracic surgery (VATS) or medical thoracoscopy with blebectomy and a procedure to induce pleurodesis (eg, surgical abrasion or chemical pleurodesis) is the first choice procedure based upon its high efficacy. For those unable or unwilling to undergo VATS, medical chemical pleurodesis at the bedside is preferred. Additionally, for patients with emphysema who meet inclusion and exclusion criteria for lung volume reduction surgery (LVRS), it may be appropriate to perform LVRS at the time of surgical pleurodesis. Further details regarding the recurrence rate and follow up of patients who undergo definitive measures are discussed separately. (See "Pneumothorax: Definitive management and prevention of recurrence" and "Treatment of primary spontaneous pneumothorax in adults", section on 'Outpatient follow-up and management'.)

After therapy, outpatient follow up is similar to that described for patients with primary spontaneous pneumothorax. In brief, patients should be evaluated clinically and radiologically in about two to four weeks after admission during which time, they are instructed to return to the hospital with symptoms of chest pain or dyspnea since recurrence is greatest during the first month after presentation. Patients should be assessed for control of their underlying lung disease, advised to stop smoking cigarettes as well as other tobacco products, marijuana, and illicit drugs, and to avoid air travel, scuba diving, and exercise for a limited period. Additional details are provided separately. (See "Treatment of primary spontaneous pneumothorax in adults", section on 'Outpatient follow-up and management'.)

OTHER PNEUMOTHORAX TYPES — The optimal management of pneumothorax associated with other etiologies is unstudied and is generally based upon biologic plausibility and experience (table 1).

●Iatrogenic/trauma – Patients with iatrogenic pneumothorax are generally treated as if they had primary spontaneous pneumothorax and few require pleurodesis unless they have a prolonged (persistent) air leak (PAL) that is not responsive to conservative therapy. Acute management of traumatic pneumothorax is discussed separately. (See "Initial evaluation and management of blunt thoracic trauma in adults", section on 'Pneumothorax' and "Initial evaluation and management of blunt thoracic trauma in adults", section on 'Occult pneumothorax'.)

●Structural abnormalities – The optimal treatment of patients with pneumothorax associated with structural abnormalities of the lung including Marfan or Ehlers-Danlos syndrome is unknown but in general they are treated in a similar fashion to those with secondary spontaneous pneumothorax based upon the assumption that recurrence is likely to be high.

●Miscellaneous – In patients with miscellaneous causes of pneumothorax including anorexia, exercise, illicit drug use, immunosuppressant drugs, air travel, or scuba diving, treatment of pneumothorax should be individualized based upon the symptoms and assessed risk of recurrence. Some societies recommend bilateral pleurectomy for deep sea divers who wish to resume diving [1]. Recommendations for patients traveling by air are provided separately. (See "Pneumothorax and air travel".)

PNEUMOTHORAX AND PREGNANCY — Our experience and case reviews support the occurrence of primary spontaneous pneumothorax (PSP) and secondary spontaneous pneumothorax (SSP) during pregnancy, although the exact incidence of either entity is unknown [20]. Older studies suggest that recurrence is greater during pregnancy, although it is plausible that recurrence is due to progression of underlying lung disease that was undetected or unsuspected following the first event.

From a management perspective during pregnancy, general principles are as follows:

●Guidelines and experts support conservative measures including aspiration and oxygen in most stable women who develop PSP during pregnancy (provided there is no evidence of fetal distress) [1,21]. Chest tube or catheter thoracostomy is appropriate for pregnant patients with SSP, patients in whom pneumothorax develops during labor and delivery, or those in whom fetal distress is evident. (See "Treatment of primary spontaneous pneumothorax in adults", section on 'Catheter or chest tube thoracostomy' and "Treatment of primary spontaneous pneumothorax in adults", section on 'Observation with or without oxygen' and "Treatment of primary spontaneous pneumothorax in adults", section on 'Aspiration'.)

●Because the risk of recurrence during future pregnancies is presumed to be high, pleurodesis should be offered to women after delivery, although case reports and anecdotal evidence report successful pregnancies without recurrence in patients in whom a definitive intervention has not been performed [20]. Similarly, experts delay investigative testing to uncover possible underlying lung disease (eg, suspicion for lymphangioleiomyomatosis in a pregnant woman with pneumothorax should be high) such as chest computed tomography and lung function testing, until after delivery. (See "Clinical presentation and diagnosis of pneumothorax" and "Clinical presentation and diagnosis of pneumothorax", section on 'Postdiagnosis evaluation'.)

●For pregnant women with or without a previous episode of pneumothorax who are at risk of developing pneumothorax during labor and delivery, close consultation with thoracic surgery, pulmonary, and obstetrics and gynecology consultants is advised. Most experts advise elective, assisted delivery at or near-term, with regional anesthesia to reduce maternal effort [1]. Regional anesthesia is also preferable in those in whom cesarean section is indicated.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Chronic obstructive pulmonary disease" and "Society guideline links: Pneumothorax".)

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●Basics topics (see "Patient education: Pneumothorax (collapsed lung) (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Assess size and symptoms – Following the diagnosis of secondary spontaneous pneumothorax (SSP; that which presents as a complication of an underlying lung disorder), clinicians should quickly estimate the size on chest radiography and assess the degree of symptomatology, so that appropriate management can be instituted. Our suggested cutoffs for size is based upon our experience and should be used as a general guideline only (see 'Definition (secondary pneumothorax)' above and 'Initial management of first event' above and 'Assessment of size and stability' above):

•Small – A space from the pleural line to the apex of <2 cm (small pneumothorax).

•Large – A space from the pleural line to the apex of ≥2 cm (large pneumothorax).

•Stability – A stable patient is one who can speak in full sentences who also has a respiratory rate <24 breaths per minute, heart rate between 60 and 120 beats per minute, normal blood pressure, and room air oxygen saturation greater than 90 percent.

●Management – The following is a reasonable strategy:

•Stable patients – For most patients with SSP, we suggest supplemental oxygen and removal of air from the pleural space by chest tube or catheter thoracostomy rather than more conservative measures (Grade 2C).

•Unstable patients – For patients who are unstable, if chest tube placement is delayed, needle decompression of the pleural space should be performed. This approach is based upon the rationale that the presence of underlying lung disease increases the likelihood of a prolonged air leak and respiratory failure thereby increasing the failure rate for conservative measures.

•Alternative approaches – Exceptions exist, and conservative measures including oxygen and observation or aspiration may be considered on a case-by-case basis for clinically stable patients who have mild or no symptoms and a small pneumothorax; in such cases, progression of symptoms or an enlarging pneumothorax are indications for pleural drainage. (See 'Management strategy' above.)

●Supportive care – Additional measures include the following (see 'General supportive care' above):

•Oxygenation and ventilation – The fraction of inspired oxygen (FiO₂) should be increased cautiously in patients who have or who are at risk for oxygen-induced hypercapnia; in addition, high-flow oxygen delivered via nasal cannulae (HFNC) and noninvasive ventilation should be avoided. Whether chest physical therapy should be avoided is unclear. (See 'Oxygen and observation' above.)

•Treat the underlying disorder – Patients should have their underlying disorder treated, and, in almost all cases, patients with SSP should be admitted because the underlying lung disease increases the risk for an adverse outcome (eg, respiratory failure, cardiovascular collapse, recurrent events). (See 'Treatment of the underlying lung disease' above and 'Disposition' above.)

•Thoracostomy management – For patients in whom a chest tube or catheter thoracostomy is indicated, a small-bore catheter (≤14 French [Fr]) or tube (≤22 Fr) is generally preferred over large-bore tubes. However, some patients may benefit from the insertion of large-bore chest tubes (24 to 28 Fr), including patients who are unstable, have concomitant empyema, hemothorax or barotrauma, or fail small-bore drainage. In general, suction is not initially applied, and the tube or catheter is connected to a water seal device. (See 'Tube or catheter thoracostomy' above.)

●Definitive intervention for first episode – For most patients with a first episode of SSP, we recommend that a definitive intervention be performed during the same hospitalization (eg, within three to five days) to prevent recurrence rather than waiting for a second event (algorithm 1) (Grade 1B). In most patients, video-assisted or medical thoracoscopy is preferred. In patients who are not good candidates for or are unwilling to undergo surgery, nonsurgical pleurodesis (eg, blood patch or chemical pleurodesis) or prolonged thoracostomy drainage are options. (See 'Preventing recurrence and follow-up' above and "Pneumothorax: Definitive management and prevention of recurrence".)

●Special populations

•Miscellaneous etiologies – The optimal management of pneumothorax associated with other etiologies (eg, iatrogenic, trauma, structural abnormalities, exercise, anorexia, drugs (table 1)) is unstudied and is generally based upon biologic plausibility and experience. (See 'Other pneumothorax types' above.)

•Pregnancy – The management of pneumothorax in pregnancy is similar to that for patients who are not pregnant except pleurodesis is generally deferred until after delivery. For those who are at risk of developing pneumothorax during labor and delivery, most experts advise a multidisciplinary approach that involves elective, assisted delivery at or near-term, with regional anesthesia to reduce maternal effort. Regional anesthesia is also preferable in those in whom cesarean section is indicated. (See 'Pneumothorax and pregnancy' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Richard W Light, MD, now deceased, who contributed to earlier versions of this topic review.