Spontaneous pneumothorax in children

INTRODUCTION — Pneumothorax in children (gas in the pleural space) is uncommon in children but can be life-threatening. It may be idiopathic or associated with underlying pulmonary disease. The prognosis is usually good, although recurrence is frequent.

Spontaneous pneumothorax in patients from infancy through adolescence will be discussed below. Pneumothorax in newborns or adults, and the placement of chest tubes, are discussed in separate topic reviews. (See "Pulmonary air leak in the newborn" and "Pneumothorax in adults: Epidemiology and etiology" and "Treatment of primary spontaneous pneumothorax in adults" and "Thoracostomy tubes and catheters: Indications and tube selection in adults and children".)

DEFINITION — Pneumothorax is defined as a collection of air that is located within the thoracic cage between the visceral and parietal pleura (image 1). Air can enter the pleural space through a leak in either pleural surface. It may flow freely within the chest or be loculated by fibrous bands or other tissues. Rarely, air accumulates due to infection with gas-producing bacteria.

A pneumothorax is characterized as either spontaneous or traumatic. Traumatic pneumothorax is caused by blunt, crush, or penetrating trauma to the chest; by injury from a diagnostic or therapeutic procedure; or as a consequence of mechanical ventilation. (See "Thoracic trauma in children: Initial stabilization and evaluation".)

Spontaneous pneumothorax, the subject of this topic review, occurs in the absence of any identified trauma. It is subdivided into primary and secondary types (table 1).

●Primary spontaneous pneumothorax (PSP) is diagnosed when a thorough investigation reveals no underlying lung disease that would predispose the individual to air leak.

●Secondary spontaneous pneumothorax (SSP) occurs as a complication of underlying lung disease, such as asthma, cystic fibrosis, necrotizing pneumonia, and interstitial lung disease.

The distinction between these types of pneumothorax is not always clear; many individuals with PSP have subtle indications of previously undiagnosed pulmonary disease, such as obstructive airway disease. In addition, apical blebs of unclear etiology have been detected by computed tomography (CT) or at the time of surgery [1].

EPIDEMIOLOGY — The annual incidence of primary spontaneous pneumothorax (PSP) in the general population is estimated to be 5 to 10 per 100,000 [1-3]. Among children and adolescents living in the United States, the incidence of PSP has been estimated to be 4 per 100,000 in males and 1.1 per 100,000 in females [4]. The peak incidence occurs between 16 and 24 years of age [3,5]. (See "Pneumothorax in adults: Epidemiology and etiology".)

The incidence of pneumothorax is relatively high in the newborn period. The reported incidence of pneumothorax in newborns and infants depends upon the setting and method of ascertainment. Small, asymptomatic pneumothoraces probably occur in 1 to 2 percent of live births, whereas symptomatic pneumothoraces occur in approximately 2 in 10,000 live births (0.02 percent). Incidence of PSP is increased among infants that are premature or large; infants with underlying lung disease including meconium aspiration are also at risk for secondary spontaneous pneumothorax (SSP). (See "Pulmonary air leak in the newborn".)

There is a strong male predominance for PSP in adults. Spontaneous pneumothorax is approximately three to six times more common in males than females [1,6-8], although women of reproductive age occasionally develop spontaneous pneumothorax triggered by menstruation (catamenial pneumothorax) (see 'Mechanisms of pneumothorax' below). There is also a male predominance among adolescents but probably not in younger children [3,5].

Risk factors — PSP typically affects patients with a tall, thin body habitus. In adults, smoking increases the risk of pneumothorax 22 times in men and 9 times in women, perhaps accounting for the higher incidence of the disorder in adults than children [9]. Pneumothorax has been reported with marijuana smoking and cocaine inhalation (table 1) [10,11].

The majority of pneumothoraces occur at rest. However, in some cases, there is a history of an activity or event unrelated to thoracic trauma but associated with an acute increase in transpulmonary pressure; reported precipitating events include military flying, weight lifting, and Valsalva maneuver [12-14]. Rarely, contact sports such as football or ice hockey can cause pneumothorax through this mechanism (barotrauma) or through blunt chest trauma with pulmonary laceration, but these would be considered a traumatic pneumothorax.

Familial cases of spontaneous pneumothorax have been described [15-17]. The majority of patients are adolescent or adult males, although newborns may be affected. Autosomal dominant and X-linked recessive inheritance has been proposed. In some cases, the familial predisposition is associated with pulmonary cysts, as in Birt-Hogg-Dubé syndrome [18]. Individuals with connective tissue disease (eg, Marfan syndrome, Ehlers-Danlos syndrome, and arterial tortuosity syndrome) might be at higher risk of developing spontaneous pneumothorax. In other cases, the exact predisposing factor cannot be identified. (See "Pneumothorax in adults: Epidemiology and etiology", section on 'Genetic predisposition'.)

Underlying pulmonary conditions associated with spontaneous pneumothorax (ie, SSP) are listed in the table (table 1) [19]. The overall incidence of SSP is similar to PSP [1]. However, the incidence of PSP peaks in adolescence and young adulthood, whereas the peak incidence of SSP occurs at an older age, largely due to the presence of chronic obstructive pulmonary disease in adults (see "Treatment of secondary spontaneous pneumothorax in adults"). In preadolescent children, rates of PSP and SSP are approximately equal [5].

MECHANISMS OF PNEUMOTHORAX — An air leak through either the visceral pleura or the parietal pleura can cause pneumothorax, but spontaneous pneumothorax occurs exclusively via rupture of the visceral pleura.

Most cases of alveolar rupture and spontaneous pneumothorax appear to be explained by either acute increase in transpulmonary pressure or defects in visceral pleura. In some cases, there is evidence for both mechanisms (eg, coughing in a patient with lung disease).

●Acute increase in transpulmonary pressure – Primary spontaneous pneumothorax (PSP) is thought to be caused by large increases in transpulmonary pressure, which cause alveolar distension. With sufficiently high pressure gradients, an alveolus can rupture. Rapid, large shifts in pressure can occur during spontaneous respiratory efforts, positive-pressure ventilation, Valsalva maneuvers, or when a ball-valve mechanism is created due to airway obstruction.

Superficial alveoli can form subpleural blebs that rupture directly into the pleural space. These blebs are usually found in the lung apices, presumably due to the selective ventilation and higher transpulmonary pressures seen in the upper lobes [20]. Alveoli located more centrally rupture, and then the free air dissects along the perivascular tissue planes, moving medially toward the hilum or peripherally toward the visceral pleural surface. Pneumomediastinum may occur if the alveolar rupture is into the mediastinum (image 2). (See "Spontaneous pneumomediastinum in children and adolescents".)

Air confined to the interstitial spaces results in pulmonary interstitial emphysema. If pressures are sufficiently high, air can rupture centrally or peripherally from the interstitial space into the pleural space to produce a pneumothorax. Similarly, air under significant pressure can track along tissue planes into the pericardium, abdomen, or subcutaneous tissue, resulting in a pneumopericardium, pneumoperitoneum, or subcutaneous emphysema, respectively (figure 1).

●Defects in visceral pleura – In some cases, a pneumothorax develops from direct injury to the visceral pleura due to underlying lung disease; these are considered secondary pneumothoraces. This mechanism may explain pneumothorax associated with infectious processes (such as tuberculosis, necrotizing pneumonia or abscess, Pneumocystis jirovecii [carinii] pneumonia, or infection in cystic fibrosis), connective tissue disease (such as Marfan syndrome or juvenile idiopathic arthritis), metastatic or embolic malignancies, congenital cystic anomalies, and catamenial pneumothorax (table 1).

Air leak associated with infection is probably due to localized inflammation and tissue necrosis that lead to the creation of a connection between the airways and pleural space (bronchopleural fistula), thereby allowing the free passage of gas into the pleural space. With tumors near the pleural surface, infarction and necrosis can lead to air leak by a similar mechanism [21].

●Catamenial pneumothorax – Catamenial pneumothorax refers to recurrent pneumothoraces that occur perimenstrually in association with thoracic endometriosis. It is rare in adolescents but has been reported [22,23]. In many cases, it is associated with thoracic endometriosis, which occurs when endometrial tissue migrates from the peritoneal cavity into the thoracic cavity through congenital diaphragmatic defects or possibly through microembolization through the pelvic veins. The mechanism for the apparent association with thoracic endometriosis is unclear; it is possible that air leaks through defects left by sloughing of endometrial implants. (See "Clinical features, diagnostic approach, and treatment of adults with thoracic endometriosis".)

PATHOPHYSIOLOGIC CONSEQUENCES — When pneumothorax occurs, the free passage of air into the pleural space allows equalization of intrapleural and atmospheric pressures, which predisposes to partial lung collapse (figure 2). A small pneumothorax may be well tolerated and asymptomatic. A large pneumothorax generally causes restrictive changes in lung mechanics with tachypnea and sometimes inspiratory retractions. (See 'Clinical features' below.)

●Invasion of related spaces – If the air is under pressure, it can track along tissue planes into the pericardium, abdomen, or subcutaneous tissue, resulting in a pneumopericardium, pneumoperitoneum, or subcutaneous emphysema, respectively. (See "Spontaneous pneumomediastinum in children and adolescents".)

●Tension pneumothorax – A tension pneumothorax is caused when air enters the pleural space during inspiration but cannot exit through the same pathway, similar to a one-way valve. This results in air accumulation within the pleural space, generating an intrapleural pressure that is substantially higher than the atmospheric pressure [24]. The inward elastic recoil of the pulmonary parenchyma causes the involved lung to collapse, while increased intrathoracic pressure causes the mediastinum to shift away from the side of the pneumothorax (figure 3). Tension pneumothorax is often associated with hypoxemia due to lung collapse, an increased work of breathing due to restrictive lung disease, and in some cases, hemodynamic changes with reduced venous return to the heart [25].

CLINICAL FEATURES — The clinical presentation of pneumothorax depends upon the volume of air in the pleural space, rapidity of onset, extent of lung collapse, tension within the pleural space, and the patient's age and respiratory reserve. The latter is influenced by the presence of any underlying pulmonary disorder.

History — Spontaneous pneumothorax most often occurs when patients are at rest or with minimal exertion. Patients with a large pneumothorax usually complain of the sudden onset of dyspnea and pleuritic chest pain that is described as sharp or stabbing and may be preceded by a popping sensation. The pain typically is diffuse on the affected side with radiation to the ipsilateral shoulder. A dry or nonproductive cough is occasionally seen in association with pneumothoraces. The pain often resolves spontaneously during the first 24 hours, even if the pneumothorax persists [1].

The history should investigate potential causes of secondary pneumothorax, such as use of inhaled drugs, undiagnosed asthma, foreign body aspiration, upper or lower respiratory tract infection, and connective tissue diseases (table 1). The presence of apical blebs supports the diagnosis of primary spontaneous pneumothorax (PSP). Otherwise, PSP is largely a diagnosis of exclusion.

A small pneumothorax may be asymptomatic. It may be detected as an incidental finding on a chest radiograph obtained for another indication.

Physical examination — Characteristic physical findings associated with a large pneumothorax include decreased chest excursion, diminished breath sounds, hyperresonant percussion, and decreased vocal fremitus on the affected side. Other signs of respiratory compromise may include tachypnea, increased work of breathing, and cyanosis.

Signs suggestive of tension pneumothorax include deviation of the trachea towards the contralateral side. Other signs of tension pneumothorax include tachycardia, hypotension, and cyanosis (figure 3). Heart sounds may be diminished and the apical impulse shifted to the contralateral side. Tension pneumothorax is a respiratory emergency and requires urgent decompression. (See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children", section on 'Tension pneumothorax'.)

Subcutaneous emphysema with crepitation, or abdominal distension due to pneumoperitoneum, is occasionally present as well.

DIAGNOSIS

Radiography — The diagnosis of pneumothorax is established by chest radiograph. When possible, the radiograph should be taken in the upright position. A pneumothorax tends to appear larger on an expiratory film and may enhance detection of small pneumothoraces. However, to monitor changes in the size of the pneumothorax over time, only inspiratory films should be compared [3]. (See 'Estimation of size' below.)

●Typical imaging features in children – Anteroposterior and lateral views can confirm the presence of even small volumes of intrapleural air (image 3). Characteristic findings are air in the pleural space outlining the visceral pleura (pleural line), hyperlucency, and an attenuation of vascular and lung markings in the lung field on the affected side. Flattening or inversion of the diaphragm may occur on the affected side, and the mediastinum and trachea may shift away from the pneumothorax. Atelectasis due to compression by the pleural gas may be present as well. There is a left-side preponderance in both pediatric and adult patients with primary spontaneous pneumothorax (PSP). (See "Atelectasis in children".)

●Features of tension pneumothorax – The following are signs of tension pneumothorax on a plain chest film:

•Contralateral mediastinal displacement

•Collapse of ipsilateral lung

•Flattening or inversion of ipsilateral diaphragm

•Widening of ipsilateral intercostal spaces

•Flattening of ipsilateral heart border

•Hyperlucent ipsilateral thorax

●CT – CT scanning is not necessary unless abnormalities are noted on the conventional chest radiograph that require further assessment [3,26]. CT may also be helpful in individuals with conditions that complicate interpretation of the conventional radiograph, such as congenital cystic lung disease (eg, congenital lobar emphysema) or congenital diaphragmatic hernia. In these cases, the lung cysts or loops of bowel filled with air may mimic air in the pleural space. CT of the chest or contrast studies (upper gastrointestinal series with small bowel follow-through) usually can distinguish these conditions. Chest CT is also helpful in the detection of small apical blebs (image 4) and in assessing chest tube placement when needed [27,28].

The clinical significance of apical blebs (<2 cm) discovered on a CT scan is unclear. The frequency of such blebs reported in the literature varies widely, ranging from 28 to 45 percent in children with PSP [19,29,30] and 0 to 15 percent in healthy children and young adults [29,31]. Several studies in children suggest that the presence of apical blebs on CT does not predict recurrence risk [3,30,32].

In our practice, we do not consider small apical blebs to be an indication for surgical intervention in a patient with a first occurrence of PSP. However, we observe patients with apical blebs closely and tend to move more quickly to surgical intervention if the patient does not improve with conservative management. (See 'Subsequent management' below.)

●Typical imaging features in infants – In infants, anteroposterior radiographs typically are obtained in the supine position. In this position, the pneumothorax is difficult to detect because the air accumulates anteriorly. However, if the pneumothorax is large, the affected side may appear hyperlucent. Detection of smaller pneumothoraces may be improved by obtaining a radiograph taken with the infant in a lateral decubitus position, with the affected side up.

In a newborn or very young infant with suspected pneumothorax, transillumination of the chest with a high-intensity fiberoptic probe in a darkened room may help make the diagnosis and guide treatment. When the fiberoptic probe is placed against the chest wall, the presence of a pneumothorax lights up the affected hemithorax and the air can be immediately evacuated [33]. (See "Pulmonary air leak in the newborn".)

Estimation of size — Several methods have been used to estimate the size of a pneumothorax in adults, based on measurements from the chest radiograph. A clinically practical measure in adults is to define a large pneumothorax as one with ≥3 cm of air between the pleural line and apical chest wall, or ≥2 cm between the entire lateral lung edge and the chest wall on an upright chest radiograph. These measurements correspond to approximately 20 to 30 percent pneumothorax, but the accuracy of these methods is limited by uneven distributions of air, in some cases, and by distortion from digital imaging. (See "Clinical presentation and diagnosis of pneumothorax", section on 'Diagnostic imaging'.)

Methods to measure the size of a pneumothorax have not been standardized in pediatric populations, but use of the adult parameters is probably reasonable in adolescent patients. For smaller children, the clinician generally categorizes the pneumothorax as "small" if it occupies <30 percent of the hemithorax and "large" if it occupies more than this proportion.

Blood gas and pulse oximetry — For all patients with suspected or confirmed spontaneous pneumothorax, pulse oximetry should be used for continuous monitoring of oxygenation while in hospital or at least until the patient is clearly clinically stable. Arterial blood gas measurements should be performed in patients with respiratory distress or low values on pulse oximetry. Pulse oximetry may not be accurate if perfusion is poor, as may occur in patients with tension pneumothorax. Hypoxemia commonly occurs because collapsed and poorly ventilated portions of lung continue to receive significant perfusion. Hypercapnia is unusual in patients without underlying lung disease because adequate alveolar ventilation can be maintained in the contralateral lung [1]. Acute respiratory alkalosis may be present if pain, anxiety, and/or hypoxemia are substantial. (See "Arterial puncture and cannulation in children" and "Measures of oxygenation and mechanisms of hypoxemia".)

Bedside ultrasound — Bedside ultrasonography is a useful tool to detect pneumothorax in selected situations, including evaluation for reexpansion after chest tube placement if the necessary expertise is available and if the clinician prefers to avoid a repeat radiograph. It is also useful for trauma patients or critically ill patients with acute respiratory failure, including those on mechanical ventilation, for whom rapid diagnosis of pneumothorax can help to avoid serious potential complications such as tension pneumothorax. Several different sonographic signs can be used to detect pneumothorax, particularly lack of lung sliding, which has a sensitivity of 86 to 98 percent and specificity of 97 to 100 percent to detect pneumothorax in adults and children with blunt trauma [34]. For critically ill patients in intensive care with nontraumatic pneumothorax, it has been suggested that the absence of lung sliding is much less specific; lung sliding is more difficult to appreciate in this group of patients [35]. Imaging of pneumothorax on ultrasonography is discussed in more detail separately. (See "Bedside pleural ultrasonography: Equipment, technique, and the identification of pleural effusion and pneumothorax", section on 'Evaluation for pneumothorax'.)

INITIAL MANAGEMENT — The management of pneumothorax has not been fully standardized, particularly for children. The British Thoracic Society [36] and the American College of Chest Physicians [37] have published guidelines on the management of adults with spontaneous pneumothorax, and other recommendations have been published [1,2,7,38]. Because little direct information is available, management in children is largely based upon the adult experience. Although indications for conservative therapy are fairly well accepted, criteria for specific drainage procedures are controversial.

Selection of treatment — In general, treatment depends upon the size of the pneumothorax, the extent of respiratory distress, and the presence or absence of underlying lung disease. The goals of treatment are to remove air from the pleural space and to prevent recurrence. (See 'Estimation of size' above.)

We suggest the following initial management strategies for children and adolescents (algorithm 1), which are similar to those used for adults:

●Stable patients with small pneumothorax – For clinically stable patients with an initial primary spontaneous pneumothorax (PSP) that is small (ie, occupying <30 percent of the hemithorax), we recommend observation in hospital. These patients usually should be given supplemental oxygen to enhance absorption of the air in the extrapleural space. However, we avoid oxygen in neonates and also avoid prolonged exposure to high concentrations of oxygen in other patients to avoid toxicity. Longer periods of observation are suggested for younger children and those with underlying lung disease (secondary spontaneous pneumothorax [SSP]). (See 'Conservative management' below.)

●Stable patients with large pneumothorax – For patients with a first occurrence of a pneumothorax that is large (eg, occupying >30 percent of the hemithorax), we suggest evacuation of the pleural space (either aspiration or continuous pleural drainage), in addition to hospital admission and supplemental oxygen. (See 'Aspiration' below.)

For stable patients with a large PSP but mild symptoms, a reasonable alternative is to observe without aspiration (conservative management). This approach is supported by a randomized trial in 316 adolescents (>15 years) and adults with moderate to large PSP, in which conservative management was as effective as interventional management (thoracostomy tube) [39]. If this approach is used, we suggest employing a protocol similar to that used in the study, in which stable patients were observed in the emergency department for at least four hours followed by repeat chest radiograph. Patients were discharged only if they did not require supplementary oxygen, were able to walk comfortably (with analgesia), and the pneumothorax did not enlarge. (See 'Conservative management' below.)

●Unstable patients – For patients with significant dyspnea, hypoxemia, or pain, we suggest continuous pleural drainage via pigtail catheter or thoracostomy tube, in addition to hospital admission and supplemental oxygen. (See 'Continuous pleural drainage' below.)

●Patients with underlying lung disease

•For most patients with a large pneumothorax due to underlying lung disease (SSP), we suggest continuous pleural drainage via a pigtail catheter or thoracostomy tube. Aspiration is a reasonable alternative for selected patients who are stable and have moderate-sized pneumothorax (see 'Continuous pleural drainage' below). Selected cases may warrant surgical intervention for the first occurrence. (See 'Indications for surgical intervention' below.)

•For patients with a small SSP, we recommend hospitalization for observation and treatment of the underlying lung disease. (See 'Observation' below.)

●Patients with recurrent pneumothorax – Patients with recurrent PSP or SSP (either ipsilateral or contralateral) should have their lung expanded with a tube thoracostomy, then undergo surgical intervention. Pleurodesis is typically performed during the thoracotomy procedure to help prevent additional recurrences. (See 'Continuous pleural drainage' below and 'Subsequent management' below.)

Conservative management

Observation — For children with a first PSP that is small (ie, occupying <30 percent of the hemithorax), we recommend observation in hospital (algorithm 1). The pneumothorax should be reassessed by chest radiograph in 6 to 12 hours. If the PSP is resolving during the first 12 hours and the patient has no pain or respiratory distress, observation may be continued on an outpatient basis. Younger patients (eg, under 12 years of age) should be observed for longer. Criteria have not been developed to guide how long to observe such a patient and how long to wait before intervention if the pneumothorax persists. However, we would generally place a thoracostomy tube within 24 to 48 hours if the pneumothorax is not improving and earlier if it is increasing in size. All patients with SSP also should be hospitalized for observation and treatment of underlying lung disease.

This strategy of using observation for children with small PSP is based upon the more extensive experience in adults. Adult patients who are having a first PSP that is small (eg, less than 2 to 3 cm of air between lung and chest wall on the radiograph) and is not enlarging and who have no respiratory distress are generally safely managed with a conservative approach. There is some evidence that such patients are less likely to experience a recurrence if managed conservatively compared with those undergoing chest tube insertion [36]. An ambulatory setting may be appropriate for adult patients, as long as serial chest radiographs are obtained and emergency care is available if needed. Management using observation alone is common for adult patients in countries outside of the United States and is frequently successful [36,40]. (See "Treatment of primary spontaneous pneumothorax in adults", section on 'Observation with or without oxygen'.)

Because of the limited data and lack of guidelines for management of pediatric PSP, we and many others use the cautious approach of observing in hospital rather than in an ambulatory setting. A multicenter observational study from Australia and New Zealand provides some information about current management approaches and outcomes in children [40]. Among 155 episodes of PSP, conservative management (no aspiration, chest tube, or surgery) was used for 59 percent of small PSPs and 20 percent of large PSPs. Among children managed conservatively, 55 percent were admitted to the hospital for observation; this rate of hospital admission for observation is higher than in most series in adults.

Supplemental oxygen — We suggest supplemental oxygen therapy for most hospitalized patients with PSP. Due to limited evidence for efficacy and concerns for oxygen toxicity, we avoid its use in neonates (except as needed to maintain oxygenation) and typically limit duration of oxygen therapy to <48 (or <72) hours for other patients. When supplemental oxygen therapy is used, it is typically delivered using a nonrebreathing facemask. High flow via nasal cannula should not be used, to minimize positive pressure to the upper airway.

For patients with underlying obstructive lung disease (causing SSP), high concentrations of oxygen can predispose to reabsorption atelectasis and should be approached with caution.

Use of supplemental oxygen is based on limited evidence from small studies in adult patients and animal models. Supplemental oxygen appears to increase the rate of reabsorption of air within the pleural space because the increased alveolar oxygen tension creates a steep gradient between the partial pressures of nitrogen in the pleural gas collection and the capillaries. In a small clinical study in adults, administration of 100 percent supplemental oxygen increased the rate of reabsorption fourfold; the beneficial effect of oxygen was most pronounced in patients with large pneumothoraces [41]. A separate observational study in adolescents and young adults with PSP also suggested that oxygen therapy probably increases the resolution rate [42] (see "Treatment of primary spontaneous pneumothorax in adults", section on 'Observation with or without oxygen'). However, retrospective studies in term infants suggested little or no advantage of supplemental oxygen for pneumothorax [43,44]. (See "Pulmonary air leak in the newborn", section on 'Management'.)

Analgesics, antitussives, and other supportive care are provided if necessary. More invasive therapy is needed in patients who fail to respond to conservative treatment or if the pneumothorax worsens.

Evacuation of the pleural space

Indications — In adults, evacuation of air is recommended for large pneumothoraces or for patients with significant dyspnea, hypoxemia, or significant pain. A large pneumothorax is often defined as ≥3 cm rim of air between the pleural line and apical chest wall in adults on an upright chest radiograph. We also use these guidelines in children. However, an individualized approach and careful monitoring of pathophysiologic consequences is important regardless of the management strategy because estimates of pneumothorax size and clinical outcomes are not well defined for this age group. (See 'Estimation of size' above.)

●For clinically stable patients with a large PSP, we suggest aspiration. However, for patients with mild symptoms, it is also reasonable to observe without aspiration. (See 'Conservative management' above.)

●Clinically unstable patients should undergo continuous pleural drainage via pigtail catheter or thoracostomy tube. (See 'Continuous pleural drainage' below.)

●For patients with an underlying lung disease (ie, SSP), management also depends on the size of the pneumothorax, but insertion of a thoracostomy tube, or a pigtail catheter, is generally preferred over aspiration. (See "Treatment of secondary spontaneous pneumothorax in adults", section on 'Initial management of first event'.)

●Patients with recurrent PSP should have their lung expanded with a tube thoracostomy, then undergo surgical intervention. (See 'Continuous pleural drainage' below and 'Failure to reexpand or recurrence' below.)

Aspiration — For clinically stable patients with a large PSP, we suggest aspiration via catheter or needle; this is also the management strategy recommended for adults. (See "Treatment of primary spontaneous pneumothorax in adults", section on 'Aspiration'.)

Simple aspiration is done percutaneously with a large-bore intravenous catheter connected to a large syringe via a three-way stopcock and can be life-saving. Air is withdrawn manually until no more can be aspirated. Continuous aspiration of a substantial volume of air indicates that the air leak is persistent and lung expansion has not occurred. In this case, tube thoracostomy should be performed. (See 'Continuous pleural drainage' below.)

If no further air can be aspirated, the stopcock is closed and the catheter is secured to the chest wall. A chest radiograph should be obtained after four hours of observation. If adequate expansion has occurred, the catheter can be removed and the patient observed for an additional two hours. Although an adult patient can be discharged if the lung remains expanded on the chest radiograph at this time [6], we recommend that children who require aspiration of a pneumothorax continue to be observed in the hospital for at least 24 hours with close monitoring or telemetry. A repeat chest radiograph should be obtained prior to considering hospital discharge.

In patients treated with aspiration, the air will reaccumulate in 20 to 50 percent because of a persistent air leak, so close follow-up with serial chest radiographs is required [1,6,7]. If the air reaccumulates, these patients should be treated with thoracostomy tube.

Continuous pleural drainage — Patients who fail aspiration treatment because of a persistent air leak, or those who present with a recurrent spontaneous pneumothorax, and many patients with SSP should be managed with continuous pleural drainage via pigtail catheter or thoracostomy tube (algorithm 1). Selection of tube and technique for placement are discussed separately. (See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children".)

Continuous pleural drainage requires the use of a one-way Heimlich valve or water seal device to prevent reaccumulation of air. If the lung does not fully expand after drainage, suction should be applied to a water seal device. Early use of strong suction is not recommended, because rapid expansion of the lung is associated with a risk of reexpansion-induced pulmonary edema. (See "Thoracostomy tubes and catheters: Placement techniques and complications", section on 'Re-expansion pulmonary edema'.)

If no bubbles emanate from the thoracostomy tube for 12 hours or more, we recommend clamping the chest tube for an additional 24 hours to observe whether air reaccumulates, although the utility of this approach is unproven. The chest tube can be removed after 24 hours if there is no radiographic or clinical evidence of recurrence of the pneumothorax. We generally repeat the chest radiograph 12 to 24 hours after removal of the chest tube.

Pleurodesis (the injection of sclerosing agents such as talc, tetracycline, fibrin glue) performed at the time of thoracostomy tube placement can decrease the risk of recurrence. The optimal method for pleurodesis in children has not been established. However, current guidelines in adults advise performing pleurodesis at the time of surgical intervention for patients requiring a preventive procedure; chemical pleurodesis through the chest tube is suggested only if the patient is unable or unwilling to undergo the surgical procedure [37]. (See "Chemical pleurodesis for the prevention of recurrent pleural effusion".)

SUBSEQUENT MANAGEMENT

Failure to reexpand or recurrence

Indications for surgical intervention — The role of surgical intervention in the treatment of spontaneous pneumothorax is somewhat controversial. There is good evidence to suggest that surgery is warranted to treat persistent air leaks. It is not yet clear whether surgery is appropriate for a first occurrence of spontaneous pneumothorax and whether such intervention will ensure the prevention of recurrence.

Most case series suggest that 50 to 60 percent of children with a first occurrence of primary spontaneous pneumothorax (PSP) will have a recurrence after conservative management with chest tube drainage; this recurrence risk is as high or higher than that reported in adults with PSP [3,30] (see 'Outcome' below). Thus, some experts suggest that surgical intervention should be considered for first occurrences as well as recurrences, if expertise in minimally invasive techniques is readily available [45,46]. Other authors suggest that surgical intervention is warranted only for recurrences [3,47,48]. Even if pleurodesis is undertaken, it does not protect against recurrence of the PSP on the contralateral side.

Based on limited evidence from case series in children and extrapolation from the observational studies and guidelines in adults, we select patients for surgical intervention as follows (algorithm 1):

●Primary spontaneous pneumothorax (PSP) – We suggest surgical intervention for children and adolescents with the following characteristics [1,37]:

•A first PSP and an air leak that fails to resolve after approximately five to seven days of thoracostomy drainage. This is the time period typically suggested for adults but is based on panels of experts rather than empiric evidence [36,37]. In patients with a first PSP, the presence of small apical blebs on CT is not an indication for immediate surgical intervention, but we observe such patients closely and tend to move more quickly to surgical intervention if the patient does not improve with conservative management.

•Recurrence of PSP (either ipsilateral or contralateral).

●Secondary spontaneous pneumothorax (SSP) – For pediatric patients with pneumothorax and underlying lung disease (ie, SSP), management strategies depend on the type and severity of the underlying lung disease. We suggest surgical intervention and a preventive intervention (eg, video-assisted thoracoscopic surgery [VATS] with pleurodesis) in the following groups of patients:

•Recurrent SSP (either ipsilateral or contralateral).

•Patients with cystic fibrosis and recurrence of a large SSP [49]. Pleurodesis using mechanical abrasion rather than chemical pleurodesis is preferred and does not preclude subsequent lung transplantation. (See "Cystic fibrosis: Overview of the treatment of lung disease", section on 'Spontaneous pneumothorax' and "Treatment of secondary spontaneous pneumothorax in adults".)

•Patients with a first episode of SSP due to other causes, if the underlying lung disease is severe, progressive, persistent, or is known to be associated with recurrent pneumothoraces. As examples:

-We perform a preventive intervention for patients with bullous lung disease.

-We do not usually perform preventive interventions for patients with mild or moderate asthma after a first occurrence of pneumothorax. Instead, the primary treatment for such patients is to optimize asthma treatment.

-Children with necrotizing pneumonia are treated with proper antibiotics and pleural space suctioning. If they develop bronchopleural fistula, surgical intervention is warranted. (See "Management and prognosis of parapneumonic effusion and empyema in children".)

A variety of other lung diseases in children can be associated with pneumothoraces, including congenital cystic lung disease, interstitial lung disease, and Marfan or Ehlers-Danlos syndromes. The recurrence risk and risk of intervention varies with the type and severity of the underlying lung disease, so treatment decisions must be made on a case-by-case basis, including the timing of surgical intervention for patients with persistent air leaks. In all cases, the occurrence of a pneumothorax should prompt efforts to fully evaluate and optimize treatment of the underlying lung disease.

For adult patients, surgical intervention is generally recommended after the first occurrence of SSP to prevent recurrence because recurrence is more common and more likely to be clinically severe for adult patients with underlying lung disease compared with those with PSP [36]. However, we use a more selective approach for children with SSP, as outlined above. Extrapolation from adult data and guidelines to pediatric practice is questionable because the type of lung disease underlying SSP varies substantially by age group.

Surgical technique — Surgery for pneumothorax consists of stapling or oversewing ruptured blebs or tears in the visceral pleura and resection of abnormal lung tissue, if present. The approaches used include VATS, mini-thoracotomy, and conventional thoracotomy [50-56]. None has been shown to be superior (see "Medical thoracoscopy (pleuroscopy): Diagnostic and therapeutic applications"). We usually use VATS, which provides adequate exposure for resection or stapling and an opportunity for abrasion or chemical pleurodesis. The morbidity of VATS is less than with conventional or mini-thoracotomy, and recurrence rates are approximately 3 percent in adults, although open thoracotomy and pleurectomy have the lowest recurrence rate [36].

Pleurodesis — For all children who undergo VATS for recurrent pneumothorax, we perform pleurodesis during the procedure to decrease the risk of recurrence. Based upon experience in adults, we routinely perform pleurodesis using manual abrasion [57]. We avoid chemical agents because they are very painful and can increase postoperative morbidity. We do not typically perform pleurodesis by instilling sclerosing agents through chest tubes, though this technique has been reported [58]. Pleurodesis using talc (poudrage) is sometimes used in adults, but we do not use this technique in children, because its long-term risks have not been sufficiently studied in this age group. In addition, technical difficulties arise because the currently available medical trocars are large and cannot be used in small children. (See "Chemical pleurodesis for the prevention of recurrent pleural effusion".)

As described above, pleurodesis may be indicated for the first episode of SSP (secondary pneumothorax), due to the high incidence of recurrence that could be life-threatening [36]. With no underlying lung disease (primary pneumothorax), the procedure is usually reserved for a recurrence. Pleurodesis also is recommended for individuals who participate in activities associated with increased risk of pneumothorax, such as deep sea diving or flying in small, unpressurized aircraft.

Resolution of pneumothorax — Once a pneumothorax has resolved after conservative management or thoracostomy tube, the patient can be discharged, with instructions to return for any new symptoms. For patients managed conservatively, we do not repeat imaging unless the patient develops new symptoms. For patients who had a thoracostomy tube, the pneumothorax should be reevaluated by chest radiograph within 12 to 24 hours after removal of the thoracostomy tube.

All patients with resolved PSP or SSP should be strongly advised not to smoke tobacco. Smoking is strongly associated with PSP in adults, and smoking cessation probably helps to prevent recurrences.

Commercial air travel in pressurized airplanes is not thought to precipitate recurrence of pneumothorax. However, the consequences of a spontaneous recurrence occurring during air travel may be serious. Therefore, guidelines for adults suggest avoidance of air travel for at least one to three weeks after full resolution of the pneumothorax [59]. In addition, most authorities suggest avoidance of sports that involve extreme exertion and physical contact until the pneumothorax is fully resolved.

Activities such as deep sea diving or flying in small, unpressurized aircrafts are associated with increased risk of pneumothorax and should be avoided in individuals who did not undergo pleurodesis.

OUTCOME — Information about the prognosis after spontaneous pneumothorax is based primarily on experience in adults, in whom there is a substantial recurrence risk [1,6,7,60]. In one review of 11 studies, pneumothorax recurred in approximately 30 percent of cases of primary spontaneous pneumothorax (PSP) managed with observation, aspiration, or chest tube [60]. The recurrence risk is similar for secondary spontaneous pneumothorax (SSP) [1]. The majority of recurrences develop within one year of the initial event, after which the risk decreases. Late recurrences are unusual.

Data on recurrent pneumothorax in children are illustrated by the following case series:

●Among 171 adolescent patients (mean age 17.6 years) with PSP, the risk of recurrence was 21 percent during a two-year follow-up [8]. A large pneumothorax with persistent air leaks was an important factor influencing recurrence. Performance of video-assisted thoracoscopic surgery (VATS) significantly reduced the risk of ipsilateral recurrence (4 percent recurrence with VATS versus 18 percent without VATS). Among those treated with VATS, 18 percent had contralateral recurrence.

●Among 58 children (median age 16.7 years) with PSP managed nonoperatively, the risk of recurrence was 51 percent after one episode and 56 percent after two [5].

●Among 27 patients with PSP whose leak initially closed during nonoperative management, 15 had ipsilateral recurrence (55 percent) and 4 had contralateral recurrence (15 percent) [61]. Among 20 patients who had persistent air leaks and were treated surgically (either VATS or thoracotomy), 3 had recurrences (15 percent). CT was not helpful in predicting which patients would experience recurrence on the contralateral side.

Thus, approximately 50 to 60 percent of pediatric patients with PSP will have a recurrence if managed conservatively (ie, without surgery or pleurodesis) [3,30]. There are insufficient data on pediatric patients to determine if the recurrence risk is similar to or higher than adults with PSP. Surgical pleurodesis greatly decreases the probability of recurrence [30,62,63].

The recurrence risk for pediatric patients with SSP is unclear but probably depends substantially on the underlying lung disease; patients with cystic fibrosis and pneumothorax have a recurrence rate of 50 to 80 percent if a preventive procedure is not performed [64], whereas a small series reported recurrence in none of seven patients with SSP associated with an acute episode of asthma [65].

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: Pneumothorax".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

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

SUMMARY AND RECOMMENDATIONS

●Definitions – Pneumothorax is defined as a collection of air that is located within the thoracic cage between the visceral and parietal pleura. Spontaneous pneumothorax occurs in the absence of any identified trauma. It is subdivided into primary and secondary types (table 1). (See 'Definition' above.)

•Primary spontaneous pneumothorax (PSP) is diagnosed when a thorough investigation reveals no underlying lung disease that would predispose the individual to air leak.

•Secondary spontaneous pneumothorax (SSP) occurs as a complication of underlying lung disease, such as cystic fibrosis.

●Epidemiology – The peak incidence of PSP occurs between 16 and 24 years of age, and it is more common in males than females. PSP also occurs in younger children and newborn infants. (See 'Epidemiology' above.)

●Clinical presentation – Spontaneous pneumothorax most often occurs when patients are at rest or with minimal exertion. Patients with a large pneumothorax usually complain of the sudden onset of dyspnea and pleuritic chest pain that is described as sharp or stabbing and may be preceded by a popping sensation. The pain typically is diffuse on the affected side with radiation to the ipsilateral shoulder. (See 'Clinical features' above.)

Findings associated with a large pneumothorax include diminished breath sounds, hyperresonant percussion on the affected side, tachypnea, increased work of breathing, and/or cyanosis. The trachea may be shifted to the contralateral side. Arterial blood gas measurements often reveal hypoxemia. (See 'Physical examination' above and 'Blood gas and pulse oximetry' above.)

●Imaging – The diagnosis of pneumothorax is established by chest radiograph. Anteroposterior and lateral views can confirm the presence of even small volumes of intrapleural air (image 3). CT of the chest may be helpful for patients with underlying pulmonary conditions or thoracic anomalies. (See 'Radiography' above.)

●Initial management – Management of spontaneous pneumothorax in children requires an individualized approach and careful monitoring of pathophysiologic consequences because estimates of pneumothorax size and clinical outcomes are not well defined for this age group. Our general approach is (algorithm 1):

•Small PSP – For clinically stable patients with an initial PSP that is small, we suggest observation in hospital rather than intervention to evacuate air from the pleural space (aspiration or tube thoracostomy) (Grade 2C). Longer periods of observation are suggested for younger children and those with underlying lung disease (secondary pneumothorax). (See 'Observation' above.)

We suggest that most patients hospitalized with PSP be given supplemental oxygen to enhance absorption of the air in the extrapleural space (Grade 2C). Due to limited evidence for efficacy and concerns for oxygen toxicity, we avoid supplemental oxygen in neonates (except as needed to maintain oxygenation) and typically limit duration of oxygen therapy to <48 hours for other patients. (See 'Supplemental oxygen' above.)

•Large PSP – For patients with a large PSP, management depends on patient characteristics (see 'Evacuation of the pleural space' above):

-For patients with a first occurrence of a pneumothorax that is large or for patients with significant dyspnea, hypoxemia, or pain, we suggest evacuation of air from the pleural space, rather than observation (Grade 1B).

-For clinically stable patients with PSP and for some patients with underlying lung disease (ie, SSP), aspiration is appropriate. For patients with mild symptoms, conservative management (observation) is a reasonable alternative. (See 'Aspiration' above and 'Conservative management' above.)

-Clinically unstable patients with PSP and most patients with SSP require continuous pleural drainage via pigtail catheter or thoracostomy tube. (See 'Continuous pleural drainage' above.)

●Surgical management

•No underlying lung disease (PSP) – For children and adolescents with PSP, we suggest surgical intervention for those with an air leak that fails to resolve after five to seven days with continuous pleural drainage or for those with recurrent PSP (Grade 2C). (See 'Indications for surgical intervention' above.)

•Underlying lung disease (SSP) – For children and adolescents with SSP, we suggest surgical intervention for patients with recurrent SSP and for those with underlying lung disease that is severe, progressive, or known to be associated with recurrent pneumothoraces (Grade 2C). For patients with cystic fibrosis, surgical intervention is not recommended for the first occurrence of pneumothorax but is recommended for any recurrence. (See 'Indications for surgical intervention' above.)

When surgical intervention is performed, video-assisted thoracoscopic surgery (VATS) with pleurodesis by manual abrasion is our preferred technique for most cases. (See 'Surgical technique' above and 'Pleurodesis' above.)