Emphysema
Pathophysiology: One of the 3 members of COLD, along with bronchitis and bronchiectasis. The histologic hallmark is permanent destruction of the underlying architecture of the lungs with disruption of inter-alveolar septae and interlobular walls as well as fixed distention of the lung. Any factor upsetting the normal lung homeostasis of micro injury-repair may predispose to emphysema.
Co-factors include: (1) smoking (2) pollutants (3) repeated airway infections (4) alpha-1 antitrypsin deficiency (5) cystic fibrosis
Clinical Clues: The prototypic "pink puffer" is a middle aged or older man with a smoking history.
CXR Findings: Emphysema typically is diffuse, but may be regional or bullous in appearance. Signs of hyperinflation:
- increase in vertical and AP dimensions of lung (barrel chest)
- increased retrosternal airspace
- flattening or eversion of the hemidiaphragms
- hyperlucency of the upper lungs (typical)
- vascular deficiency with decreased vascularity and smaller than normal vessels in the involved lungs
Clinical Complications: Oxygen desaturation and accompanying vasoconstriction ultimately leading to secondary polycythemia and pulmonary arterial hypertension with resultant cor pulmonale and heart failure. Repeated infections due to associated bronchitis and other factors.
"Aunt Sophies":
- physiologic (eg. young man with big inspiration)
- compensatory hyperinflation (physiologic),
- bad technique with "black" overpenetrated films
- regional air-trapping (eg. endobronchial lesions, cystic fibrosis, asthma)
- bullae, pneumatoceles, post-infection lung cavities may mimic regional bullous emphysema
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