The introduction of air into the pleural
space separates the visceral from the parietal pleura
In contradistinction, the visceral and
parietal pleura usually do not separate from each other in
obstructive atelectasis
Pathophysiology
Either from disruption of visceral pleura
Or, trauma to parietal pleura
Clinical findings
Acute onset of
Pleuritic chest pain
Dyspnea (in 80-90%)
Cough
Back or shoulder pain
Etiologies
Penetrating trauma
Blunt trauma
May be due to rib fracture
May be caused by increased intrathoracic
pressure
May lead to bronchial rupture
“Fallen lung sign” (ptotic lung sign)
-- hilum of lung is below expected level within chest
cavity
Persistent pneumothorax with
functioning chest tube
Iatrogenic
Tracheostomy
Central venous catheter attempt or
insertion
Mechanical ventilation
May occur in up to 25% of patients
maintained on PEEP
May be bilateral or under tension
Thoracic irradiation
Spontaneous pneumothorax
Most common etiology
Cause
Rupture of subpleural blebs in apical
region of lung
Age
20-40 years
M:F = 8:1
Especially in patients who are tall
and thin
Smokers
Prognosis
Recurrence in 30% on same side
Recurrence in 10% on contralateral
side
Treatment
Simple aspiration (success in >50%)
Tube thoracostomy (effective in 90%)
Other causes of a pneumothorax
Neonatal disease
Meconium aspiration
Respirator therapy for hyaline
membrane disease
Malignancy
Primary lung cancer
Lung metastases, especially from
osteosarcoma
Also pancreas, adrenal, Wilms tumor
Pulmonary infections
Tuberculosis
Necrotizing pneumonia
Coccidioidomycosis
Hydatid disease
Pertussis
Acute bacterial pneumonia
Staphylococcal septicemia
AIDS (Pneumocystis carinii,
Mycobacterium tuberculosis, atypical mycobacteria)
Complication of pulmonary fibrosis
Histiocytosis X
Idiopathic
Cystic fibrosis
Sarcoidosis
Scleroderma
Eosinophilic granuloma
Interstitial pneumonitis
Rheumatoid lung
Idiopathic pulmonary hemosiderosis
Pulmonary alveolar proteinosis
Biliary cirrhosis
Asthma or emphysema
Produce a second peak incidence of
pneumothorax from 45-65 years of age
Due to rupture of peripheral
emphysematous areas
“Catamenial pneumothorax” is a recurrent
spontaneous pneumothorax that occurs during menstruation and
is associated with endometriosis of the diaphragm
R >> L
Marfan’s syndrome
Ehlers-Danlos syndrome
Pulmonary infarction
Lymphangiomyomatosis and tuberous
sclerosis
Incidence of pneumothorax is
particularly high in lymphangiomyomatosis and histiocytosis
X
Types of pneumothorax
Closed pneumothorax = intact thoracic cage
Open pneumothorax = "sucking" chest wound
Tension pneumothorax
Accumulation of air within pleural space
due to free ingress and limited egress of air
Pathophysiology:
Intrapleural pressure exceeds atmospheric pressure in lung during
expiration (check-valve mechanism)
Frequency
In 3-5% of patients with spontaneous
pneumothorax
Higher in barotrauma (mechanical
ventilation)
Simple pneumothorax –no shift of the heart
or mediastinal structures
Imaging findings in pneumothorax
Must see the visceral pleural white line
Very thin white line that differs from a
skin fold by its thickness
Absence of lung markings distal or
peripheral to the visceral pleural white line
Not evidence enough to say there is a
pneumothorax only if there are no lung markings seen
No lung markings will be seen with
bullous disease
Bullae have a concave surface facing
the chest wall
Pneumothorax almost always has a
convex surface facing the chest wall
Displacement of mediastinum and/or
anterior junction line
Deep sulcus sign
On frontal view, larger lateral costodiaphragmatic recess than on
opposite side
Diaphragm may be inverted on side with
deep sulcus
Total / subtotal lung collapse
This is passive or compressive atelectasi
Collapse of SVC or IVC due to decreased
systemic venous return and decreased cardiac output
Tension hydropneumothorax
Sharp delineation of visceral pleural by
dense pleural space
Mediastinal shift to opposite side
Air-fluid level in pleural space on erect
chest radiograph
Radiographic signs in upright position
White margin of visceral pleura separated
from parietal pleura
Usually seen in the apex of the lung
Absence of vascular markings beyond
visceral pleural margin
May be accentuated by an expiratory film
in which lung volume is reduced while amount of air in
pneumothorax remains constant so that relative size of
pneumothorax appears to increase
Radiographic signs in supine position
Anteromedial pneumothorax (earliest
location)
Outline of medial diaphragm under cardiac
silhouette
Deep sulcus sign
Decubitus views of the chest may
demonstrate a pneumothorax on the side that is non-dependent
Left lateral decubitus view for
right-sided pneumothorax
Right lateral decubitus view for
left-sided pneumothorax
Subpulmonic pneumothorax (second most common
location)
Hyperlucent upper abdominal quadrant
Deep lateral costophrenic sulcus
Sharply outlined diaphragm in spite of
parenchymal disease
Visualization of anterior costophrenic
sulcus
Visualization of inferior surface of lung
Apicolateral pneumothorax (least common location)
Visualization of visceral pleural line
Posteromedial pneumothorax (in presence of
lower lobe collapse)
Lucent triangle with vertex at hilum
V-shaped base delineating costovertebral
sulcus
Pneumothorax outlines pulmonary ligament
Pitfalls in diagnosis
Skin fold
Thicker than the thin visceral pleural
white line
Air trapped between chest wall and arm
Will be seen as a lucency rather than a
visceral pleural white line
Edge of scapula
Follow contour of scapula to make sure
it does not project over chest
Overlying sheets
Usually will extend beyond the confines
of the lung
Hair braids
Prognosis
Resorption of pneumothorax occurs at a
rate of 1.25% per day (accelerated by increasing inspired oxygen
concentrations)
Left pneumothorax-deep sulcus sign., Lucency at left costophrenic angle which
projects well below the
costophrenic angle on the opposite side is the "Deep sulcus sign"
indicating the
presence of a pneumothorax on a supine radiograph of the chest
(Bullet is seen overlying the heart)
Thoracic
Radiology: The Requisites
Dahnert 4th Edition
