Pulmonary emphysema: acute, compensatory, focal, interstitial and senile emphysema
Conditions related to emphysema
- Compensatory emphysema
- Alveoli compensate for damage to lung parenchyma by dilation and attempt to improve lung function. Also known as compensatory overinflation.
- Obstructive overinflation
- Obstruction of the bronchi, causes lung expansion due to trapped air, often caused by FB or tumour
- Bullous emphysema
- Any emphysema that produces large subpleural blebs (spaces greater than 1cm in the distended state) which represent localised forms of emphysema
- Interstitial emphysema
- Air enters CT stroma of the lung, mediastinum and subcutaneous tissue. This can occur spontaneously with sudden alveolar pressure increase (e.g. violent coughing that results in a tear).
- Air can then travel in subcutaneous tissue and can cause marked subcutaneous swelling of the patient (commonly around the head and/or neck)
Gross: bullous emphysema. A large, thin-walled subpleural bulla (an emphysematous space over 1 cm) occupies the apex; rupture can cause pneumothorax.
Image: “Bullous emphysema (4857852447)” by Yale Rosen from USA, CC BY-SA 2.0, via Wikimedia Commons.
Remember: acute emphysema is a reversible acute overinflation of the lung, e.g. during a severe asthma attack or in agonal breathing. Senile emphysema is age-related enlargement of alveolar ducts and alveoli with loss of elastic recoil, without inflammation or significant airflow obstruction. Neither is true destructive (obstructive) emphysema.