Pediatric Pneumothorax 

Updated: Oct 16, 2019
Author: Andres Carrion, MD, FAAP; Chief Editor: Girish D Sharma, MD, FCCP, FAAP 

Overview

Practice Essentials

Pneumothorax is the accumulation of air in the space between the lungs and chest wall, termed called the pleura. Most pneumothoraces occur spontaneously, but they can also occur in association with trauma or some preexisting pulmonary or systemic conditions. Although not common in children, pneumothorax can sometimes be life-threatening.

Symptoms develop suddenly, with a sharp chest pain and shortness of breath. Physical examination may reveal decreased breath sounds in the affected area. Tension pneumothorax presents with more severe symptoms and respiratory distress. In such cases, diagnosis and prompt intervention should not be delayed.

Pneumothorax can be confirmed with an upright inspiratory chest radiograph. A small pneumothorax may not be apparent on the chest radiograph. CT scanning is recommended for unusual cases or when evaluating a patient with recurrence.

Many cases of spontaneous pneumothorax resolve with conservative therapies. Administration of high-concentration oxygen helps reabsorption of air. Large, complicated, or tension pneumothorax requires decompression and chest tube placement.

Background

Pneumothorax refers to the accumulation of air or gas in the pleural space that enters through disruption of any surface of the pleura.

Classification is as follows:

  • Spontaneous pneumothorax: This occurs without known disease or a precipitating factor. It can be further categorized as primary (idiopathic) pneumothorax or secondary pneumothorax.
  • Secondary pneumothorax: This occurs as a complication of a chronic or acute lung disease. It is usually associated with higher morbidity and mortality than primary spontaneous pneumothorax. [1]
  • Traumatic pneumothorax: This is caused by blunt or penetrating trauma to the chest.
  • Iatrogenic pneumothorax: This is a complication of certain diagnostic or therapeutic procedures such as central line placement.

Pneumothoraces can also be classified as either simple or complicated, depending on size, symptoms, progression, and recurrence. The size of a pneumothorax is not as important as the degree of clinical compromise.[1]

See the images below.

Pneumothorax; left side. Pneumothorax; left side.

Pathophysiology

Spontaneous pneumothorax occurs via rupture of the visceral pleura, whereas traumatic pneumothorax may occur following injury to either pleural layer. In both types, a loss of intrapleural negative pressure causes lung collapse. The main physiologic consequences of a pneumothorax are a decrease in vital capacity and a decrease in partial pressure of oxygen (PaO2). Most patients with a pneumothorax have a reduced PaO2 and an increased alveolar-arterial gradient. The reduction in PaO2 appears to be caused by areas with low ventilation-perfusion ratios, anatomic shunts, and alveolar hypoventilation.[2]

Simple pneumothorax occurs when air in the pleural space does not build up significant pressure but allows the lung to collapse without further expansion of the pneumothorax. Usually, small pneumothoraces are asymptomatic and well tolerated.

Complicated pneumothorax consists of continued air leakage into the pleural space that cannot exit during exhalation, resulting in progressive lung collapse. The positive pressure within the hemithorax causes a collapse of the involved lung and a shift of the mediastinal structures to the contralateral side, creating a tension pneumothorax, a life-threatening emergency. This causes a decrease in cardiac output as a consequence of decreased venous return that could lead to rapidly progressive shock and cardiorespiratory arrest if not recognized and treated. Secondary pneumothorax can be a potential life-threatening event in patients with lung disease because they may already have decreased cardiopulmonary reserve.

Note the image below.

Tension pneumothorax in an infant. Tension pneumothorax in an infant.

Etiology

The most common risk factors for pneumothorax are smoking, male gender, family history of spontaneous pneumothorax, tall lean body habitus, premature delivery, and obstructive pulmonary disease. Pneumothorax can be associated with Valsalva maneuver, but it is usually not associated with physical exertion as it is as likely to occur during sedentary activity.[1, 3] Air leak usually occurs from rupture of apical blebs, as opposite to distention along the intrapulmonary vascular bundle, with subsequent air leakage into the pleural space. Inhalation of some toxic substances (eg, crack cocaine) can also lead to this condition.

Spontaneous secondary pneumothoraces may occur in patients with underlying lung diseases or any disease that promotes air leakage, such as asthma or cystic fibrosis.[4] These patients also have a high risk of recurrence, especially if pleural blebs or bullae are the cause of the pneumothorax.[3] The presence of an apical cyst or bullae in other patients is not necessarily predictive of recurrence.[5, 6]

Other conditions associated with the development and recurrence of spontaneous pneumothorax include parenchymal diseases (eg, interstitial lung disease, emphysema), infections (eg, necrotizing pneumonia, tuberculosis, pneumonia in immunocompromised hosts), malignancy (eg, lymphoma, metastasis), and connective-tissue disorders (eg, Marfan syndrome, Ehlers-Danlos syndrome, juvenile idiopathic arthritis, systemic lupus erythematosus, polymyositis, dermatomyositis, sarcoidosis, Langerhans cell histiocytosis, alpha-1 antitrypsin deficiency, Birt-Hogg-Dubé syndrome).[3] Spontaneous pneumothorax is also common in patients with lymphangioleiomyomatosis.

When trauma results in pneumothorax, it may be secondary to blunt or penetrating trauma. Penetrating trauma results in an open or communicating pneumothorax.

Iatrogenic causes of pneumothorax include central line placement, thoracentesis, cardiothoracic surgery or biopsy, mechanical ventilation, and cardiopulmonary resuscitation.

Epidemiology

Although all age groups are affected, the peak incidence of pneumothorax occurs in individuals aged 16-64 years.[7] In the pediatric population, the overall incidence of pneumothorax is 5-10 cases per 100,000 children younger than 18 years. The rate of pneumothorax is relatively higher during the newborn period.[8] Primary spontaneous pneumothorax may have a higher recurrence rate in children than in adults. There is a strong (6:1) male predominance for spontaneous pneumothorax. It can also present in reproductive-age girls as catamenial pneumothorax.[1, 5]

Prognosis

The prognosis is often favorable, especially if it was an isolated event and treatment was initiated early. Prognosis also varies depending in patient’s underlying disease and pulmonary reserve. If other trauma was sustained at the same time or tension pneumothorax occurred with subsequent shock and hypoperfusion, the prognosis worsens. If the patient was allowed to be hypoxic for a long period, brain injury is possible.

Recurrence after the first episode of primary spontaneous pneumothorax in children is frequent and difficult to predict.[9] The recurrence rate of spontaneous pneumothoraces can range from 40-87%. The risk of recurrence is increased if the initial episode was slow to resolve and if there is ongoing cigarette smoking following the development of spontaneous pneumothorax. A high incidence of recurrence is noted after the first episode of a secondary pneumothorax and in patients who participate in activities such as deep sea diving. Patients with obstructive pulmonary disease (eg, asthma, cystic fibrosis) have an especially high rate of recurrence.[3, 4]

Patient Education

For patient education information, see the Lung Disease and Respiratory Health Center and the patient education article Collapsed Lung (Pneumothorax).

 

Presentation

History

The severity of symptoms depends on the amount of air leakage, extent of lung collapse, rate of development, etiology, and underlying clinical status of the patient.

The most common symptoms are chest pain and dyspnea. Sometimes, patients report a popping sensation at the onset of symptoms. Spontaneous pneumothorax often occurs when a patient is at rest or with minimal exertion. Patients who are symptomatic may report a sudden onset of pleuritic chest pain that is sharp or stabbing. Patients with small pneumothoraces may occasionally have a dry or nonproductive cough.

A patient with a simple pneumothorax may also present with no symptoms, and it is found as an incidental finding on a chest radiograph. Symptoms of a small pneumothorax can resolve in 24 hours. Patients with a spontaneous pneumothorax secondary to preexisting lung disease may have a more dramatic presentation.

Premature neonates on mechanical ventilation may develop a pneumothorax as a result of positive pressure and respiratory system compliance, presenting with a quick deterioration and shock.

Physical Examination

Careful assessment of vital signs should be done, as hypotension and hypoxemia can be present.

Findings are more pronounced with a large pneumothorax. An extensive pneumothorax often produces pleuritic chest pain, dyspnea, tachypnea, and cyanosis. Chest auscultation can range from mild decrease in aeration to complete absence of breath sounds on the affected side. In addition, hyperresonance to percussion may be noted on the affected side. Subcutaneous emphysema with crepitance is occasionally present.

Patients with a tension pneumothorax typically present in shock with severe respiratory distress and may have tracheal deviation to the unaffected side as a late sign.

If the pneumothorax is due to trauma, there could be areas of contusions or abrasions on the chest wall or a small puncture wound that does not allow free movement of air between the outside and the pleural cavity. Flail chest with paradoxical chest motion can also be seen.

Complications

Complications may include the following:

  • Cardiac tamponade
  • Cardiopulmonary arrest
  • Hemothorax
  • Pneumopericardium
  • Pneumomediastinum
  • Shock
  • Tension pneumothorax

See the images below.

Pneumomediastinum. Pneumomediastinum.
Tension pneumothorax. Tension pneumothorax.

Also see Treatment/Complications. 

 

DDx

Diagnostic Considerations

The evaluation of patients presenting with a spontaneous pneumothorax should always include the investigation of potential causes such as use of inhaled drugs, foreign body aspiration, infections, underlying asthma, and connective-tissue diseases.

Differential Diagnoses

  • physical abuse or non-accidental trauma

 

Workup

Approach Considerations

A thorough history and physical examination usually lead to the diagnosis of a pneumothorax. Urgency, age, and cooperation of the child are some of the factors that should be taken under consideration when selecting imaging studies, because rapid worsening of the condition can occur before radiographs are obtained, especially in the setting of a tension pneumothorax. The size of the pneumothorax determines the rate of resolution and is a relative indication for active intervention.[1]

Chest radiography is the standard imaging for confirming a pneumothorax. Both CT scanning and thoracoscopy have proven useful for detecting blebs in case of recurrent or slow-to-resolve air leaks. Further investigation and pleurodesis should be considered in such cases.

Chest Radiography

Pneumothorax is generally a clinical diagnosis that is confirmed with upright chest radiography. Anteroposterior (AP) and lateral views can reveal the presence of even small amounts of intrapleural air. Air in the pleural space that outlines the visceral pleura is a characteristic finding. Hyperlucency of vascular and lung markings on the affected side can be seen because of this air. Atelectasis may also be seen on the affected side due to compression by pleural air, and the mediastinum and trachea may shift away from the pneumothorax in the case of tension pneumothorax.

Lateral decubitus chest radiographs may be useful, especially in infants, as small pneumothoraces may be difficult to see on supine AP radiographs because the air accumulates anteriorly.

There is no standard method to measure the size of pneumothoraces in pediatric patients. The British Thoracic Society guidelines differentiate a large from a small pneumothorax by the presence of a visible rim of greater than 2 cm between the lung margin and the chest wall (at the level of the hilum). Per other sources, a pneumothorax is considered small if the distance between the lung apex and the ipsilateral dome of the thoracic cavity on an upright chest radiograph is less than 3 cm, and large if greater than 3 cm.[1]

Laboratory Studies

Arterial blood gas (ABG) assessment should be obtained in patients with respiratory distress. Multiple abnormalities can be seen on ABG measurements in a patient with a pneumothorax. Hypoxemia frequently occurs due to ventilation-perfusion mismatch in the affected lung. The collapsed portion of the lung affected by pneumothorax is poorly ventilated but continues to receive adequate perfusion, which leads to hypoxemia. Patients may also have acute respiratory alkalosis on ABG assessment if they have significant pain, anxiety, and/or hypoxemia.

Other Imaging Studies

A noncontrast chest CT scan is rarely required for diagnosis of a pneumothorax. CT scanning may be useful to further evaluate abnormalities seen on chest radiography, in detection of small blebs, or in distinguishing preexisting pulmonary pathologies. CT may also be useful in the diagnosis of secondary pneumothorax, as these patients have lower respiratory reserve and are more likely to require a procedure for even a small pneumothorax seen on imaging.

Ultrasonography has also been useful in detecting pneumothorax in adults, but similarly to chest radiography, it is difficult to estimate size of pneumothorax using ultrasonongraphy. The utility of ultrasonography in the pediatric population has not consistently been well described in the literature.

Transillumination of the thorax with a high-intensity fiberoptic probe may be helpful in guiding the diagnosis in newborns and infants.

 

Treatment

Approach Considerations

Treatment for spontaneous pneumothorax in children varies based on the size of the pneumothorax, severity of respiratory distress, and presence of underlying lung disease. Many cases of spontaneous pneumothorax resolve with conservative therapies. Individuals with small pneumothoraces who are asymptomatic can be observed and do not necessarily require intervention. Pneumothorax should resolve within 12 days. Although subcutaneous emphysema can be extensive, it does not create an increased risk of local infections. Management of subcutaneous emphysema should be focused on symptoms.[3, 6]

Administering 100% oxygen via a nonrebreathing face mask hastens the absorption of loculated gas. High concentrations of supplemental oxygen create a partial-pressure gradient between the pleural cavity and end-capillary blood by decreasing the partial-pressure contribution of nitrogen (nitrogen washout), increasing reabsorption of gas from the pleural cavity.[2] This treatment should not be continued for long periods. The patient should be observed and chest radiography should be repeated to look for improvement. For secondary spontaneous pneumothorax, underlying disease should be treated.

Large (occupying >30% of the hemithorax) or complicated pneumothorax requires hospitalization and direct mechanical evacuation of pleural air. Clinically stable patients with a primary spontaneous pneumothorax can be treated with needle aspiration. Clinically unstable patients and most patients with underlying lung disease (secondary spontaneous pneumothorax) should be treated with chest tube insertion. A patient with a traumatic pneumothorax is best treated with a chest tube, because the condition may rapidly convert into a tension pneumothorax, especially if positive-pressure ventilation is applied. A tension pneumothorax requires immediate decompression with needle thoracostomy, followed by tube thoracostomy.[1]

In certain conditions with recurrent pneumothorax (such as cystic fibrosis), identification of an apical bleb sometimes requires thoracoscopic resection, and if no bleb is found, then either thoracoscopic or sclerosing pleurodesis is indicated.

See the image below.

Pneumothorax chest tube. Pneumothorax chest tube.

Medical Care

There is no general consensus on the best setting to monitor pediatric patients with small pneumothoraces; however, a cautious approach in these patients is usually appropriate. Clinically stable patients with small, primary spontaneous pneumothoraces can be initially observed in the hospital with administration of 100% supplemental oxygen via a nonrebreathing facemask. If the pneumothorax is small and is resolving within 12 hours, patients can generally be observed in an outpatient setting. Younger children may require longer observation in a hospital setting.

Other supportive care, including pain medications, should be provided as needed to all patients with pneumothorax.

Patients should have close outpatient follow-up and should also be given specific instructions to seek further medical care should they develop any new or worsening dyspnea or other respiratory symptoms.

Surgical Care

Evacuation of the pleural space is recommended for a large pneumothorax or in patients with significant pain, dyspnea, or hypoxemia. Pneumothorax in adults is generally considered to be large if there is 3 or more centimeters of air between the pleural line and the apical chest wall; however, it is difficult to determine the size of a pneumothorax in a pediatric patient as the thoracic size differs based on age and the size of the patient.

Only pleurodesis (intrapleural instillation of a sclerosing agent such as talc, fibrin glue, and antibiotics), video-assisted thoracoscopic surgery (VATS), and thoracotomy reduce the risk of future recurrence. Pleurodesis may be indicated for the first episode of a secondary pneumothorax owing to the high incidence of recurrence or after a recurrence of a primary pneumothorax.

Needle decompression is appropriate for clinically stable patients with large primary spontaneous pneumothoraces. In needle aspiration, air is manually withdrawn using an intravenous catheter connected to a syringe and three-way stopcock. Follow-up chest radiography should be performed approximately 4 hours after the procedure, and catheter can be removed at that time if adequate lung expansion has occurred. A persistent air leak is likely present if a substantial volume of air can be continuously withdrawn during needle aspiration. Air can also reaccumulate as a result of a persistent air leak after needle decompression; therefore, serial chest radiographs are important during close follow-up. Patients with reaccumulation of air require thoracostomy tube placement.

Thoracostomy (chest) tube is required in patients in whom needle aspiration fails as a result of a persistent air leak, patients with recurrent spontaneous pneumothorax, and some patients with secondary spontaneous pneumothorax. Pleurodesis can be performed at the time of thoracostomy tube placement to help decrease risk of recurrence of pneumothorax.

VATS with pleurodesis is generally indicated in patients with primary spontaneous pneumothorax and persistent air leak that fails to improve with thoracostomy tube. VATS is also considered in recurrent primary or secondary spontaneous pneumothorax, but it should be considered on a case-by-case basis.[7, 10, 11]

Complications

Complications directly related chest tube insertion may result in significant bleeding, infection, or both. Other complications of thoracostomy include pain and injury to thoracic neurovascular structures. Insertion too far below the recommended fourth or fifth intercostal space may result in intra-abdominal placement, with possible abdominal visceral or diaphragmatic injury.

Tension pneumothorax is a rare but serious potential complication of either primary or secondary spontaneous pneumothorax.

Also see Presentation/Complications.

Consultations

The following consultations may be needed:

  • Critical care specialist
  • Surgeon
  • Pulmonologist
  • Interventional radiologist

Activity

To decrease the risk of recurrence, children should avoid scuba diving. Additionally, on a temporary basis, 4 weeks after resolution of pneumothorax, all air travel, contact sports, and playing bass or woodwind musical instruments is to be avoided.[3]

Prevention

It is strongly encouraged to avoid smoking exposure, and efforts should be directed at smoking cessation after the development of a pneumothorax.

Long-Term Monitoring

There is a high rate of pneumothorax recurrence after a VATS procedure or chest tube drainage. Close follow-up is recommended.

 

Guidelines

Guidelines Summary

There is a lack of pediatric evidence to guide management. In a study, Soccorso et al concluded that the British Thoracic Society guidelines for the management of spontaneous pneumothorax are not applicable to children with large primary spontaneous pneumothorax. Needle aspiration is ineffective, and CT scanning should be used to assess apical emphysematous-like changes and secondary pathological conditions for pneumothorax.[5, 12]