Pneumothorax

Respiratory Collapsed lung

Air leaking into the space around a lung, breaking its seal so the lung collapses.

Educational summary only — not medical advice, and no substitute for assessment by a clinician. Diagrams are simplified illustrations.

Air leaks into the sealed space around a lung; with nothing holding it open, the lung collapses inward like a deflated balloon.

Overview

The lungs sit inside the chest within a sealed space and stay inflated thanks to a vacuum-like seal around them. A pneumothorax is when air leaks into that space (the pleural space), breaking the seal and allowing some or all of the lung to collapse.

How the system normally works

Each lung is wrapped in a thin double membrane (the pleura) with a slippery, sealed layer between. The slight suction in this layer keeps the elastic lung stretched open against the chest wall, so it expands and recoils as you breathe.

What goes wrong

If air enters the pleural space — from a tiny air-filled blister (bleb) on the lung's surface bursting, from an injury, or from a medical procedure — the seal is lost. The naturally elastic lung then recoils and collapses, partly or fully, so it can no longer take in air properly. In the dangerous tension form, air keeps entering but can't escape, building pressure that pushes the heart and other lung aside and chokes off blood return.

Side-by-side diagram comparing a normal lung held open by the pleural seal and a collapsed lung after air enters the pleural space. — Normally a thin sealed layer (the pleural space) holds the lung open against the chest wall; let air in and the elastic lung springs inward.

Symptoms and why they happen

Sudden, sharp, one-sided chest pain — the membranes and sudden change.
Shortness of breath that came on quickly — reduced working lung.
Fast breathing and heart rate.
Severe breathlessness, blue lips, and collapse — suggest a tension pneumothorax.

Causes and risk factors

Tall, thin young people (spontaneous, from a ruptured bleb)
Smoking and lung diseases such as COPD or asthma
Chest injury or rib fracture
Some medical procedures on the chest

How it's diagnosed

A chest X-ray usually confirms it and shows the size; CT gives more detail. In a collapsing, critically unwell patient a tension pneumothorax is diagnosed clinically and treated immediately, without waiting for imaging.

Diagram of a tension pneumothorax with trapped air pushing the heart and windpipe toward the opposite side of the chest. — In a tension pneumothorax, trapped air builds pressure that shoves the heart and windpipe to the other side — rapidly life-threatening.

Treatment and management

A small pneumothorax in a well person may simply be observed as the air reabsorbs. Larger ones are treated by removing the trapped air — needle aspiration or a chest drain (a tube placed between the ribs). A suspected tension pneumothorax is decompressed urgently with a needle, then a drain. Recurrent cases may need a procedure to seal the lung surface.

Possible complications

Recurrence, incomplete re-expansion, and — for tension pneumothorax — circulatory collapse if not treated immediately.

Prevention and outlook

Stopping smoking lowers the risk of a first or repeat episode. Most simple pneumothoraces resolve well with treatment, though recurrence is possible, especially in those prone to blebs.

When to seek emergency care

Severe breathlessness, blue lips, or collapse — possible tension pneumothorax; call emergency services.
Sudden one-sided chest pain and breathlessness after injury.