AUTHOR AND EDITOR INFORMATION

Section 1 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• MISCELLANEOUS
• Acknowledgments
• Multimedia
• References

INTRODUCTION

Section 2 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• MISCELLANEOUS
• Acknowledgments
• Multimedia
• References

Background

Pneumothorax is air in the potential space between the visceral and parietal pleura of the lung. Air can enter the intrapleural space through a communication from the chest wall or through the lung parenchyma across the visceral pleura.  

Pneumothoraces secondary to trauma are relatively straightforward and usually require tube thoracostomy. Spontaneous pneumothorax, however, is a commonly encountered problem with approaches to treatment that can vary from observation to aggressive intervention. This article focuses on differentiating primary spontaneous (no obvious underlying lung disease), secondary spontaneous (underlying lung disease), and iatrogenic pneumothoraces (which are traumatic but typically are smaller and more easily managed). In addition, pneumomediastinum (free air in the mediastinal structures) is discussed.

Classification

Primary spontaneous pneumothorax

• Air in the intrapleural space without preceding trauma and without underlying clinical or radiologic evidence of lung disease
• Typically in patients who are between 18 and 40 years

Secondary spontaneous pneumothorax

• Occurs in patients with underlying pulmonary structural pathology
• Air can enter the pleural space via distended, damaged, or compromised alveoli
• May present with more serious clinical symptoms and sequelae due to comorbidity

Iatrogenic pneumothorax

• Medical procedure resulting in traumatic pneumothorax (usually from a small bore hollow needle)

Pneumomediastinum

• Gas in the mediastinal structures can occur spontaneously or following procedures or trauma
• Pneumothorax can occur secondary to pneumomediastinum

Pathophysiology

Spontaneous pneumothoraces in most patients occur from the rupture of blebs and bullae. While primary pneumothorax is defined as a lack of underlying pulmonary disease, these patients have blebs and bullae detected on CT scans or upon thoracotomy. These may be due to congenital abnormalities or increased shear forces at the apex of the lung. Until a bleb ruptures and causes a pneumothorax, no clinical signs or symptoms are present. 

The pleural space has a negative pressure, with the chest wall tending to spring outward and the lung's elastic recoil tending to collapse. If the pleural space is invaded by gas from a ruptured bleb, the lung collapses until equilibrium is achieved or the rupture is sealed. As the pneumothorax enlarges, the lung becomes smaller.

The main physiologic consequence of this process is a decrease in the vital capacity and a decrease in the partial pressure of oxygen. Young and otherwise healthy patients can tolerate these changes fairly well, with minimal changes in vital signs and symptoms, but those with underlying lung disease may have respiratory distress.

With pneumomediastinum, excessive intra-alveolar pressures lead to rupture of perivascular alveoli. Air escapes into the surrounding connective tissue, with subsequent dissection into the mediastinum. Air may then dissect superiorly into the visceral, retropharyngeal, and subcutaneous spaces of the neck. From the neck, the subcutaneous compartment is continuous throughout the body; thus, air can diffuse widely. Mediastinal air can also pass inferiorly into the retroperitoneum and other extraperitoneal compartments. If the mediastinal pressure rises abruptly or if decompression is not sufficient, the mediastinal parietal pleura may rupture and cause a pneumothorax (in 10-18% of patients).

Frequency

United States

Incidence of primary spontaneous pneumothorax (age-adjusted) is 7.4-18 cases per 100,000 persons per year for men and 1.2-6 cases per 100,000 persons per year for women. Incidence of secondary spontaneous pneumothorax (age-adjusted) is 6.3 cases per 100,000 persons per year for men and 2 cases per 100,000 persons per year for women. Chronic obstructive pulmonary disease (COPD) is a common cause of secondary spontaneous pneumothorax that carries an incidence of 26 cases per 100,000 persons. It is likely that the incidence for spontaneous pneumothorax is underestimated. Up to 10% of patients may be asymptomatic, and others with mild symptoms may not present to a medical provider. 

The incidence of iatrogenic pneumothorax is not known, but it probably occurs more often than primary and secondary spontaneous pneumothoraces combined. Pneumomediastinum occurs in approximately 1 case per 10,000 hospital admissions.

Mortality/Morbidity

• Although some view primary spontaneous pneumothorax as more of a nuisance than a major health threat, deaths have been reported. Secondary spontaneous pneumothoraces can be life threatening, depending on the severity of the underlying disease and the size of the pneumothorax. Compared with similar patients without pneumothorax, age-matched patients with COPD have a 3.5-fold increase in relative mortality when a spontaneous pneumothorax occurs. Mortality percentages in patients with COPD and spontaneous pneumothorax vary from 1-17%.
• Iatrogenic pneumothorax may cause substantial morbidity and, rarely, death.
• Pneumomediastinum is generally a benign, self-limited condition. Malignant pneumomediastinum (unvented mediastinal or pulmonary adventitial air causing pressure so high that circulatory or ventilatory failure occurs) was described in 1944; all patients in this report had serious comorbid conditions. No reports of fatal outcomes in patients with spontaneous pneumomediastinum in the absence of underlying disease exist in the recent literature. The mortality rate is as high as 70% in patients with pneumomediastinum secondary to Boerhaave syndrome, even with surgical intervention.

Sex

Incidence is higher in men than in women, at a ratio of 6.2:1 for primary pneumothorax and 3.2:1 for secondary pneumothorax.

A slight predominance exists for males with pneumomediastinum.

Age

• Primary spontaneous pneumothorax occurs most often in persons early in the third decade of life and rarely occurs in persons older than 40 years.
• Secondary spontaneous pneumothoraces occur more frequently after age 60 years.
• Spontaneous pneumomediastinum generally occurs in young, healthy patients without serious underlying pulmonary disease, mostly in the second to fourth decades of life.

CLINICAL

Section 3 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• MISCELLANEOUS
• Acknowledgments
• Multimedia
• References

History

Acute onset of chest pain, often pleuritic and associated with shortness of breath, is typical. Both of these symptoms occur in 64-85% of patients. Chest pain in primary spontaneous pneumothorax often improves over the first 24 hours, even without resolution of the underlying air accumulation. Well-tolerated primary pneumothorax can take 12 weeks to resolve. In secondary pneumothorax, chest pain is more likely to persist with more significant clinical symptoms. 

A primary spontaneous pneumothorax usually develops at rest, and many affected individuals do not seek medical attention for days after symptoms develop. This trend is important, because the incidence of reexpansion pulmonary edema increases in patients whose chest tubes have been placed 3 or more days after the pneumothorax occurred.

Smoking increases the risk of a first spontaneous pneumothorax by more than 20-fold in men and by nearly 10-fold in women compared with risks in nonsmokers. Increased risk of pneumothorax and recurrence appears to rise proportionally with number of cigarettes smoked.

The most common underlying abnormality in secondary spontaneous pneumothorax is COPD. Cystic fibrosis carries one of the highest associations, with more than 20% reporting spontaneous pneumothorax.

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

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

Symptoms of primary and secondary spontaneous pneumothorax, iatrogenic pneumothorax, and pneumomediastinum may include the following:

• Spontaneous pneumothorax
• • Chest pain (acute onset, ipsilateral)
  • Dyspnea (in secondary cases may be disproportionate to the size of the pneumothorax)
  • Cough
  • Generalized malaise (In one old series, 3% of patients had generalized malaise, while 6.5% were asymptomatic.) 
• Iatrogenic pneumothorax: Symptoms are similar to those of a spontaneous pneumothorax and, depend on the age of the patient, presence of underlying lung disease, and extent of the pneumothorax.
• Pneumomediastinum: Patients may or may not have symptoms, as this is typically a well-tolerated disease, although mortality in cases of esophageal rupture is very high.
• • In a recent retrospective review of cases presenting to an academic medical center from 1993-2000, 24 patients were identified. Of these, 67% had chest pain; 42% had persistent cough; 25% had sore throat; and 8% had dysphagia, shortness of breath, or nausea/vomiting.
  • Substernal chest pain, usually radiating to the neck, back, or shoulders and exacerbated by deep inspiration, coughing, or supine positioning
  • Dyspnea
  • Neck pain
  • Jaw pain
  • Dysphagia, dysphonia, and/or abdominal pain (unusual symptoms)

Physical

The general appearance of the patient may vary from asymptomatic to respiratory distress. Findings on lung auscultation also vary depending on the extent of the pneumothorax, but they may include diminished or absent breath sounds, or hyperresonance on percussion of the affected side. General clinical signs include the following:

• Spontaneous pneumothorax
• • Tachycardia (most common)
  • Tachypnea
  • Hypoxia
• Iatrogenic pneumothorax: Signs are similar to those of spontaneous pneumothorax and depend on the underlying lung disease and extent of the pneumothorax.
• Pneumomediastinum
• • Subcutaneous emphysema (most consistent sign)
  • Hammas sign (precordial crunching noise synchronous with the heartbeat, often accentuated during expiration; occurrence varies—one series reported 10%.)
  • None (Physical findings are absent in some patients.)

Causes

Causes of pneumothorax and pneumomediastinum may include the following:

• Primary spontaneous pneumothorax
• • Spontaneous pneumothorax is heavily associated with smoking, with 80-90% of primary spontaneous pneumothorax cases occurring in smokers.
  • Physical height: It has been noted that typical patients tend to have a tall and thin body habitus. Whether height affects development of subpleural blebs or whether more negative apical pleural pressures cause preexisting blebs to rupture is unclear.
  • Valsalva results in increased intrathoracic pressure. However, contrary to popular belief, most spontaneous pneumothoraces occur while the patient is at rest.
  • Changes in atmospheric pressure, proximity to loud music, and low frequency noises have also been reported to be associated with pneumothorax
  • Familial associations have been noted in more than 10% of patients. Some are due to rare connective tissue diseases, but recently, mutations in the gene encoding folliculin (FLCN) have been described. These patients may represent an incomplete penetrance of a genetic disorder. Birt-Hogg-Dube syndrome is characterized by benign skin growths, pulmonary cysts, and renal cancers and is caused by mutations in the FLCN gene.
• Secondary spontaneous pneumothorax
• • COPD or emphysema
  • Asthma
  • Cystic fibrosis
  • Interstitial lung disease
  • Tuberculosis
  • Bronchogenic or metastatic carcinoma
  • Pneumonia (fungal, caseating, HIV)
  • Collagen vascular disease including Marfan syndrome
  • Catamenial pneumothorax (see Special Concerns)
• Iatrogenic pneumothorax
• • Transthoracic needle aspiration procedures (most common cause, accounting for 32-37% of cases)
  • Subclavian and supraclavicular needle sticks
  • Thoracentesis
  • Mechanical ventilation (directly related to peak airway pressures)
  • Pleural biopsy
  • Transbronchial lung biopsy
  • Cardiopulmonary resuscitation (Consider the possibility of a pneumothorax if ventilation becomes progressively more difficult.)
  • Tracheostomy
• Pneumomediastinum
• • Acute production of high intrathoracic pressures (usual cause)
  • Asthma
  • Smoking marijuana
  • Inhalation of cocaine
  • Athletic competition
  • Respiratory tract infection
  • Parturition
  • Emesis
  • Severe cough
  • Mechanical ventilation
  • Trauma or surgical disruption of the oropharyngeal, esophageal, or respiratory mucosa

DIFFERENTIALS

Section 4 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• MISCELLANEOUS
• Acknowledgments
• Multimedia
• References

WORKUP

Section 5 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• MISCELLANEOUS
• Acknowledgments
• Multimedia
• References

Imaging Studies

• Chest radiography for evaluation of pneumothorax
• • Although expiratory images are thought to better depict subtle pneumothoraces (the volume of the pneumothorax is constant and hence proportionally higher on expiratory images), a randomized controlled trial revealed no difference in the ability of radiologists to detect pneumothoraces on inspiratory and expiratory images.
  • In patients with underlying pulmonary disease, the classic visceral pleural line may be harder to detect because the lung is hyperlucent, and little difference exists in the radiographic density between the pneumothorax and the emphysematous lung.
  • Ratio of lung size to hemithorax size to estimate pneumothorax size avoids the subjective underestimation of pneumothorax expressed as a percentage of previous lung volume
  • • The size of a pneumothorax may be estimated by using the ratio of the lung diameter cubed to the hemithorax diameter cubed.
    • This formula assumes a constant shape of the lung when it collapses and is invalid if pleural adhesions are present.
  • A simple approach to classification of the pneumothorax as small or large involves measuring the distance from the apex of the lung to the top margin of the visceral pleura (thoracic cupola) on the upright chest radiograph.
  • • Small pneumothorax: <3 cm distance to the apex
    • Large pneumothorax: >3 cm distance to the apex
  • A supine chest radiograph may depict the deep sulcus sign (very dark and deep costophrenic angle). The anterior costophrenic recess becomes the highest point in the hemithorax, resulting in an unusually sharp definition of the anterior diaphragmatic surface due to gas collection and a depressed costophrenic angle.  
• Chest radiography for evaluation of pneumomediastinum
• • Mediastinal emphysema appears as a thin line of radiolucency that outlines the cardiac silhouette, as well as thin, lucent, vertically oriented streaks of air within the mediastinum.
  • The aorta and other posterior mediastinal structures are highlighted, and a well-defined lucency around the right pulmonary artery (ring around the artery sign) may be seen.
  • Air most easily is detected retrosternally on the lateral chest radiograph. An anteroposterior chest radiograph may not depict the finding in 50% of cases.
  • Unlike air in a pneumothorax or pneumopericardium, the air remains fixed in pneumomediastinum and does not rise to the highest point.
• Contrast-enhanced esophagography: If emesis or retching is the precipitating event, an esophagogram should be obtained to evaluate for Boerhaave syndrome (an esophageal tear), which has a high mortality rate. This is the study of choice in all cases of suspected esophageal perforation (ie, postendoscopy patients). Esophagoscopy could further be performed for esophageal perforations.
• CT of the thorax
• • When performed on primary spontaneous pneumothorax patients, CT detects multiple blebs and bullae in the setting of negative chest radiographic findings; this may not impact management, as there has been no correlation between bleb appearance and recurrence.
  • CT can detect occult pneumothorax in patients who will require mechanical ventilation in trauma and emergency surgery settings.
  • CT has also been shown to be more sensitive than radiography for hemothorax and pulmonary contusion.
  • While the role of CT in trauma patients is evolving, it is controversial whether it significantly alters management and is not indicated in primary spontaneous pneumothorax.
  • CT may have a role in secondary spontaneous pneumothorax, especially to differentiate from giant bullous emphysema.
  • CT may improve diagnostic sensitivity in pneumomediastinum, and if clinical suspicion is present, should be obtained. One small study suggested that mild pneumomediastinum was underdiagnosed based on chest radiographic findings, and CT was needed to make the diagnosis.
• Ultrasonography
• • Ultrasonography can be used as a possible bedside technique to detect pneumothorax.
  • It may be useful in unstable patients who cannot undergo radiologic studies outside of the emergency department.
  • Ultrasonography is operator dependent.

Procedures

• Tube thoracostomy
• • If the patient is hemodynamically stable, consider conscious sedation with careful titration of a short-acting narcotic and benzodiazepine.
  • Place the patient in a 30-60° reverse Trendelenburg position. Scrub the site (centered around the fifth or sixth rib in the midaxillary line) with povidone-iodine (Betadine), alcohol, or both.
  • Locally anesthetize the site with lidocaine. (Use a generous amount, and anesthetize all the way down to the pleura.)
  • Make a 3- to 4-cm incision.
  • Use a curved hemostat, puncture (in a controlled manner) through the intercostal muscles and parietal pleura immediately superior to the rib border, avoiding damage to the underlying lung. Spread the hemostat wide to create an adequate opening.
  • Perform a digital examination to assess the presence and location of pulmonary adhesions. Sweep the finger in all directions, and feel for the diaphragm and possible intra-abdominal structures. To avoid losing the desired tract, some recommend keeping the finger in place until the tube is inserted.
  • Insert the chest tube along the finger; use a clamp on the tube, if desired.
  • Direct the chest tube posteriorly, and insert it until it is at least 5 cm beyond the last hole in the tube.
  • Attach the tube to a water seal and vacuum device (eg, Pleur-Evac). Look for respiratory variation of the water seal and bubbling of air through the water seal. Document the amount of blood or other fluids drained.
  • Suture the site, and secure the tube to the chest wall. Cover the site with Vaseline-impregnated gauze, and apply a suitable dressing. A variety of anchoring and closure techniques exist, all of which are probably equivalent.
  • Obtain a chest radiograph to confirm placement and lung reexpansion.
• Needle aspiration
• • Palpate the rib and intercostal space intended for needle aspiration. For air aspiration, the anterior approach at the second or third intercostal space at the midclavicular line or a lateral approach at the fifth or sixth intercostal space at the midaxillary line is appropriate. Instill a local anesthetic as deep as to the pleura, directing the needle over the top of the rib into the desired intercostal space.
  • Insert a 16-gauge Angiocath or ready-to-use aspiration kit into the fourth or fifth intercostal space at the anterior axillary line.
  • Remove the needle once the pleural cavity is entered, and attach the catheter to 3-way stopcock and 60-mL syringe.
  • Withdraw air continually until no more can be aspirated (discontinue if resistance is felt, if the patient coughs excessively or if more than 2.5 L is aspirated). Close the stopcock, and secure the catheter to the chest wall.
  • Obtain a chest radiograph to assess the degree of success, and obtain another radiograph 4 hours later to confirm the absence of recurring accumulation.
  • If no recurrence is present, remove the catheter, and discharge the patient with appropriate return instructions. (Some authors suggest observation for an additional 2 h after catheter removal.)
  • If the pneumothorax persists, attach a Heimlich valve or a water seal and admit the patient.
• Needle decompression
• • Emergent intervention for tension pneumothorax should be performed prior to radiologic evaluation.
  • A large-bore (18 or 16 gauge) angiocatheter is introduced in the midclavicular line at the second or third intercostal space. This serves as a bridge until the definitive treatment of tube thoracostomy. The catheter is left in place until the chest tube is placed.

• Pleurodesis (See Further Inpatient Care).

TREATMENT

Section 6 of 12  

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• Clinical
• Differentials
• Workup
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• Medication
• Follow-up
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• Acknowledgments
• Multimedia
• References

Prehospital Care

• Assess the ABCs, and evaluate the possibility of a tension pneumothorax. Assess the vital signs, and perform pulse oximetry. A tension pneumothorax is almost always associated with hypotension.
• Administer oxygen to the patient, and establish an intravenous line.
• Most paramedics are trained to perform needle decompression for immediate relief of a tension pneumothorax.

Emergency Department Care

Immediate attention to the ABCs while assessing vital signs and oxygen saturation is paramount. ED care depends on the hemodynamic stability of the patient. All patients should receive supplemental oxygen to increase oxygen saturation and to enhance the reabsorption of free air. Treatments for primary and secondary spontaneous pneumothorax are the following:

• Primary spontaneous pneumothorax
• • If the pneumothorax is smaller than 15% and if the patient is symptomatic but hemodynamically stable, aspiration is the treatment of choice.
  • If the pneumothorax is smaller than 15% and if the patient is asymptomatic, many consider observation to be the treatment of choice. (If the patient is admitted, administer oxygen, since this has been shown to speed resolution of the pneumothorax.)
• Secondary spontaneous pneumothorax
• • Tube thoracostomy is the procedure of choice.
  • Pleurodesis decreases the risk of recurrence, as does thoracotomy or video-assisted thoracoscopy to excise the bullae.
• Iatrogenic pneumothorax: Aspiration is the technique of choice for iatrogenic pneumothoraces because recurrence usually is not a factor.
• Most patients with pneumomediastinum should be admitted and observed for signs of serious complications (eg, pneumothorax, tension pneumothorax, mediastinitis). If the pneumomediastinum occurred from the inhalation of cocaine or smoking of marijuana, observation in the ED for progression may be indicated.

Consultations

Physicians from various services may be needed to care for patients who require tube thoracostomy and admission. A surgeon and a pulmonologist should evaluate patients with multiple recurrent diseases to determine the cause and further management.

MEDICATION

Section 7 of 12  

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The goals of pharmacologic therapy are to reduce symptoms and prevent potential complications.

Drug Category: Anesthetic

Anesthetic agents are used for analgesia in the treatment of sclerotic lesions.

Drug Category: Benzodiazepine

These agents are useful for premedication prior to sclerosis and placement of a thoracostomy tube.

Drug Category: Analgesic

Pain control is essential to good patient care. It ensures patient comfort and promotes pulmonary toilet. Most analgesics have sedating properties, which are beneficial for patients with painful skin lesions. Analgesics are important in the initial placement of thoracostomy tubes and for controlling pain after the procedure.

FOLLOW-UP

Section 8 of 12  

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• Follow-up
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• Multimedia
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Further Inpatient Care

• Prophylactic antibiotics: Although no data support the use of prophylactic antibiotics, many physicians routinely treat patients with antibiotics until the chest tube is removed.
• Analgesics: Patients may require analgesics for comfort until the thoracostomy tube is removed. Some authors advocate the use of intercostal nerve blocks to increase patient comfort and decrease the need for analgesics.
• Suction: Strong suction should not be used with a spontaneous pneumothorax because of the increased risk of reexpansion pulmonary edema.
• Video-assisted thoracoscopic surgery  
• • Video-assisted thoracoscopic surgery (VATS) has been replacing thoracotomy in the treatment of chronic or persisting pneumothoraces. Particularly for pediatric patients, it has been shown to have better outcomes and shorter recovery.
  • Indications include an unexpanded lung 5 days after tube thoracostomy, bronchopleural fistula persisting for 5 days or longer, recurrent pneumothorax after chemical pleurodesis, and occupational reasons (eg, airplane pilots, deep-sea divers).
• Pleurodesis: This treatment decreases chance of pneumothorax recurrence. It should be performed just after reinflation of the lung if the presence of an air leak is not a contraindication. The 2 major sclerosing agents are talc and tetracycline derivatives (eg, minocycline, doxycycline). This procedure should be performed in consultation with the surgeon.
• • Talc (5-10 g in 250 mL sterile isotonic sodium chloride solution) usually is insufflated during video-assisted thoracoscopic surgery or thoracotomy, but one study of 32 patients demonstrated findings of successful treatment with a chest tube (10% recurrence at 5 y).
  • In a large Department of Veterans Affairs study, tetracycline pleurodesis had a 25% recurrence in patients compared with 41% in control subjects. However, tetracycline no longer is available for pleurodesis because of stringent manufacturing requirements. Minocycline and doxycycline have been shown to be successful sclerosing agents. Bleomycin was found to be ineffective in rabbits and is expensive.
  • Sclerosis is painful, and the patient should be premedicated with benzodiazepine and intrapleural lidocaine.
  • Physical disruption and scraping of the pleura can also induce scarring in pleurodesis.
• Follow-up for pneumomediastinum
• • A follow-up chest radiograph should be obtained in 12-24 hours to detect any progression or complication, such as pneumothorax.
  • If no progression occurs at 24 hours and if no evidence of mediastinitis exists, the patient may be discharged.

Further Outpatient Care

• Heimlich valve placement
• • The Heimlich valve is a one-way, rubber flutter valve. The proximal end attaches to the chest tube or catheter, and the distal end connects to a suction device or is left open to the atmosphere.
  • It can allow outpatient treatment of a pneumothorax.

Deterrence/Prevention

• Smoking cessation is strongly advised for all patients. Whether primary or secondary pneumothorax, smoking increases the likelihood of bleb rupture and recurrence, and does so in a predicable, dose-related manner.
• Ascent from deep-sea diving causes gases to expand and can lead to pneumothorax in patients with bullae and blebs. Patients with previous spontaneous pneumothoraces are at risk for recurrence and are advised not to dive unless thoracotomy or pleurodesis has been performed.
• Commercial air travel achieves minimal change in gas volumes due to pressurization of the cabin. However, spontaneous pneumothorax has been described during commercial travel, and patients with resolving pneumothorax are cautioned not to fly until intrapleural air has completely resolved.

Complications

• Reexpansion pulmonary edema
• • This condition is a unilateral pulmonary edema that rarely occurs after reinflation of a collapsed lung.
  • Incidence, etiology, risks, and mortality rates are controversial.
  • Findings from animal studies and several case reports in humans indicate that reexpansion pulmonary edema may occur more often if a pneumothorax is present longer than 3 days and if suction is applied. This information is important because in one study, 46% of patients waited more than 2 days after their symptoms started to seek medical attention, and, in another study, 18% waited more than 7 days.
  • For spontaneous pneumothoraces, suction should not be applied because of an often-delayed presentation and, thus, an increased risk of reexpansion pulmonary edema. In addition, one study revealed that the rate of lung reexpansion is independent of suction.
  • Reexpansion pulmonary edema can occur in the opposite lung.
• Tension pneumothorax
• • A worsening pneumothorax, usually with a one-way valve phenomenon, can allow air into the intrapleural space and prevent its escape, causing mediastinal shift, pulmonary shunting, and circulatory collapse.
  • Treatment of tension pneumothorax is emergent and should be performed prior to confirmatory radiologic studies.
  • Needle decompression is performed prior to definitive treatment with tube thoracostomy. (See Procedures.)
  • In mechanically ventilated patients, high pressures and air trapping place patients at risk for tension pneumothorax if the thoracostomy is not functioning. Patients with smaller pneumothoraces that would otherwise be managed with aspiration or observation sometimes undergo thoracostomy because of the need for mechanical ventilation.
• Accidental disconnection and malpositioning of Heimlich valves can complicate an attempted outpatient treatment of pneumothorax via pigtail catheter.

Prognosis

• The prognosis is generally good with appropriate therapy.

MISCELLANEOUS

Section 9 of 12  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• MISCELLANEOUS
• Acknowledgments
• Multimedia
• References

Special Concerns

• HIV
• • While pneumonia is a possible cause of pneumothorax, in the patient with HIV, the pathogens include Pneumocystis carinii (PCP) pneumonia, toxoplasmosis, and Kaposi sarcoma. A patient with HIV can have spontaneous pneumothorax as the presenting symptom of the illness. 
  • HIV carries a lifetime risk of 6% for pneumothorax, about 85% of that number is related to PCP pneumonia.
• Catamenial
• • A rare cause of recurrent pneumothorax in women, catamenial is thought to arise from endometriosis reaching the chest wall across the diaphragm. Prior to recurrence, it may be initially diagnosed as primary spontaneous pneumothorax. 
  • Onset of symptoms within 48 hours of menstruation, right-sided pneumothorax, and recurrence raise suspicion for this disease. It is rarely treated surgically, and oral contraceptives carry a high success rate.
• Familial
• • Folliculin gene disorders are being described in familial spontaneous pneumothorax. These patients may have pneumothorax as the presenting symptom of Birt-Hogg-Dube disease. Some authors recommend screening patients with a family history of pneumothorax for the benign skin tumors and renal cancers that arise from the disease. 
  • Since primary spontaneous pneumothorax patients will have apical emphysematous pulmonary disease on CT or thoracoscopy, they can be thought to have a congenital syndrome of mild acinar emphysema, whose expression is enhanced by environmental factors (eg, smoking) just as it is in patients with alpha-1-antitrypsin deficiency and "typical" emphysema.

ACKNOWLEDGMENTS

Section 10 of 12  

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• Follow-up
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• Multimedia
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The authors and editors of eMedicine gratefully acknowledge the contributions of previous author, Erik D Barton, MD, to the development and writing of this article.

MULTIMEDIA

Section 11 of 12  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• MISCELLANEOUS
• Acknowledgments
• Multimedia
• References

Media file 1:  This is a chest radiograph of an elderly male with chronic obstructive pulmonary disease who presented with a second left-sided spontaneous pneumothorax in 2 months. Chest thoracostomy was performed, the patient was admitted, and talc pleurodesis was performed the next day.
	View Full Size Image
Media type:  Radiograph

Media file 2:  This chest radiograph shows pneumomediastinum (radiolucency noted around the left heart border) in this patient who had a respiratory and circulatory arrest in the ED after experiencing multiple episodes of vomiting and a rigid abdomen. The patient was taken immediately to the operating room, where a large rupture of the esophagus was repaired.
	View Full Size Image
Media type:  Radiograph

REFERENCES

Section 12 of 12

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• MISCELLANEOUS
• Acknowledgments
• Multimedia
• References

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Article Last Updated: Nov 14, 2007