Atelectasis is reversible.

• A. Reversible
• B. Irreversible
• C. Progressive
• D. Fatal

Answer: (A)

Atelectasis represents collapse of lung regions that can usually re-expand when the underlying cause is addressed. If airway obstruction (like a mucus plug or a tumor) is relieved or if external pressure (such as a pleural effusion or pneumothorax) is removed, air can re-enter the alveoli and the collapsed tissue can re-expand toward normal volume. This reversibility is the defining feature you’re tested on: the lung tissue itself isn’t permanently damaged in most cases, so the condition tends to improve with treatment.

While persistent or prolonged atelectasis can sometimes become associated with scarring or be part of a more complex lung process, the basic concept is that atelectasis is reversible when the triggering factor is resolved. It’s not inherently irreversible, progressive, or fatal as a property of the atelectasis itself.