Pneumotorax

Pneumothorax
Glenna B. Winnie
Pneumothorax is the accumulation of extrapulmonary air within the chest. It is uncommon during childhood. Most often, pneumothorax results from leakage of air from within the lung. Air leaks can be primary or secondary and can be spontaneous, traumatic, iatrogenic, or catamenial ( Table 410-1 ). Pneumothorax in the neonatal period is also discussed in Chapter101.13 .

TABLE 410-1   -- Causes of Pneumothorax in Children
SPONTANEOUS |
Primary idiopathic—usually resulting from ruptured subpleural |
Secondary blebs |
Congenital lung disease |
 Congenital cystic adenomatoid malformation |
 Bronchogenic cysts |
 Pulmonary hypoplasia |
Conditions associated with increased intrathoracic pressure |
 Asthma |
 Bronchiolitis |
 Air-blocksyndrome in neonates |
 Cystic fibrosis |
 Airway foreign body |
Infection |
 Pneumatocele |
 Lung abscess |
 Bronchopleural fistula |
Diffuse lung disease |
 Langerhans cell histiocytosis |
 Tuberous sclerosis |
 Marfan syndrome |
 Ehlers-Danlos syndrome |
Metastatic neoplasm—usually osteosarcoma (rare) |
TRAUMATIC |
Noniatrogenic |
   | | Penetrating trauma |
   || Blunt trauma |
   | | Loud music (air pressure) |
|
Iatrogenic |
   | | Thoracotomy |
   | | Thoracoscopy, thoracentesis |
   | | Tracheostomy |
   | | Tube or needle puncture |
   | | Mechanical ventilation |
|
From Kuhn JP, Slovis TL, Haller JO: Caffey's Pediatric Diagnostic Imaging, vol 1, 10th ed. Philadelphia, Mosby, 2004, p 885.
*Renal agenesis, diaphragmatichernia, amniotic fluid leaks. |

|

ETIOLOGY AND EPIDEMIOLOGY.
A primary spontaneous pneumothorax occurs in someone without trauma or underlying lung disease. Spontaneous pneumothorax with or without exertion (Valsalva) occurs occasionally in teenagers and young adults, most frequently in males who are tall, thin, and thought to have subpleural blebs. Families in which many members have hadspontaneous pneumothoraces, with the onset ranging from birth to adulthood, have been described. Patients with collagen synthesis defects such as Ehlers-Danlos disease (see Chapter 658 ) and Marfan syndrome (see Chapter 700 ) are unusually prone to the development of pneumothorax.
A pneumothorax arising as a complication of an underlying lung disorder but without trauma is a secondaryspontaneous pneumothorax. Pneumothorax can occur in pneumonia, usually with empyema; it can also be secondary to pulmonary abscess, gangrene, infarct, rupture of a cyst or an emphysematous bleb (in asthma), or foreign bodies in the lung. In infant staphylococcal pneumonia, the incidence of pneumothorax is relatively high. It is found in ≈5% of hospitalized asthmatic children and usually resolves withouttreatment. Pneumothorax is a serious complication in cystic fibrosis (CF; see Chapter 400 ). Pneumothorax also occurs in patients with lymphoma or other malignancies, and in graft vs host disease with bronchiolitis obliterans.
External chest or abdominal blunt or penetrating trauma can tear a bronchus or abdominal viscus, with leakage of air into the pleural space. Ecstasy(methylenedioxymethamphetamine) abuse has been associated with pneumothorax.
Iatrogenic pneumothorax can complicate tracheotomy, subclavian line placement, thoracentesis, transbronchial biopsy, or other diagnostic or therapeutic procedures. Pneumothorax may also occur after acupuncture treatment.
Catamenial pneumothorax, an unusual condition that is, by definition, associated with menses, results from passage ofintra-abdominal air through diaphragmatic defects.
Pneumothorax can be associated with a serous effusion (hydropneumothorax) or a purulent effusion (pyopneumothorax). Bilateral pneumothorax is rare beyond the neonatal period but has been reported after lung transplantation and with Mycoplasma pneumoniae infection and tuberculosis.
PATHOPHYSIOLOGY.
The tendency of the lung to collapse, or elastic...