Pulmonary contusion !

A bruise of the lung after a blow to the chest. Bleeding and swelling in the lung tissue make breathing harder over the next one to two days.

Updated 2026-11-01

Structures involved

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Why it happens

What it is

Bruising of the lung parenchyma after blunt chest trauma, with bleeding and oedema in the alveoli and interstitium but no laceration of the lung surface. It is the most common lung injury in blunt chest trauma and often lies under rib fractures or a flail segment.

Who gets it

Found in a large share of patients with significant blunt chest trauma, and commoner in children and young adults, whose flexible chest wall transmits energy to the lung without breaking ribs. In Colombia and Latin America, motorcycle and car crashes, pedestrian injuries and falls from height are the usual mechanisms.

Causes

Road traffic crashes (motorcycle riders, unrestrained occupants, pedestrians)
Falls from height
Crush injuries and direct blows to the chest
Blast injuries
High-velocity gunshot wounds (cavitation around the track)

Risk factors

High-energy mechanism
Multiple rib fractures or flail chest
Young age (compliant chest wall)
Chronic obstructive pulmonary disease or chronic kidney disease (higher need for ventilation)
Large-volume fluid resuscitation

Pathophysiology

The impact disrupts alveolar capillaries, so blood and fluid fill the alveoli and interstitium. Surfactant loss and local inflammation cause alveolar collapse. The contused area keeps being perfused but is poorly ventilated, producing shunt and ventilation-perfusion mismatch with hypoxaemia. The injury typically worsens over 24–72 hours and then resolves over about a week; large contusions predispose to pneumonia and ARDS.

Classification

By extent on CT: small versus large (often expressed as the percentage of lung volume involved, with more than about 20% predicting respiratory failure)
Unilateral versus bilateral
Isolated versus associated with flail chest, pneumothorax or haemothorax

Symptoms and signs

Chest pain and chest wall tenderness
Shortness of breath that may increase gradually
Tachypnoea and tachycardia
Cough, sometimes with blood (haemoptysis)
Reduced breath sounds or crackles over the injured area

Diagnosis

Clinical: Suspect it in any patient with blunt chest trauma and breathing difficulty, especially when it worsens over hours. ATLS primary survey, then serial clinical assessment and continuous pulse oximetry.
Tests: Arterial blood gas (hypoxaemia, low PaO2/FiO2 ratio, hypercapnia when tiring) and capnometry; baseline trauma blood tests.
Imaging: Chest X-ray shows patchy, non-segmental opacities that may not appear for 24–48 hours. CT of the chest is far more sensitive, shows the extent early and detects associated rib fractures, pneumothorax and haemothorax.

Differential diagnosis

Aspiration pneumonitis or pneumonia
Haemothorax
Pulmonary laceration with haematoma
Fat embolism syndrome
ARDS from another cause

Goal of treatment

Keep oxygenation and ventilation adequate while the lung heals, control pain so the patient can breathe deeply and cough, and prevent pneumonia and fluid overload.

Treatment

Acute: ATLS approach, supplemental oxygen, and treatment of associated pneumothorax or haemothorax with chest drainage.
Medical: Effective analgesia (multimodal, including regional techniques such as epidural or nerve blocks in multiple rib fractures) to allow deep breathing and coughing.
Conservative: Judicious fluid resuscitation aimed at normal perfusion while avoiding excess fluid; chest physiotherapy, incentive spirometry and early mobilisation.
Procedure: Non-invasive ventilation in selected alert patients; intubation and lung-protective mechanical ventilation for respiratory failure. Corticosteroids and prophylactic antibiotics are not used routinely.
Follow-up: Nursing priorities: continuous pulse oximetry, respiratory rate and work of breathing, pain scores, fluid balance, positioning, and early signs of pneumonia.

Complications

Acute respiratory failure
Pneumonia
ARDS
Pneumatocele or lung abscess
Long-term reduced lung function after large contusions

Prognosis

Most contusions resolve within about 5–7 days. Outcome depends on the size of the contusion and on associated injuries; large or bilateral contusions carry a higher risk of ventilation, pneumonia and ARDS.

Prevention

Seatbelts, airbags and child restraints
Motorcycle safety and speed control
Fall prevention at work and at home

Test yourself

Think of the answer, then tap the question to see it.

Why may the first chest X-ray look normal in a patient with pulmonary contusion?

Opacities often take 24–48 hours to appear on plain film; CT shows the contusion much earlier.

What is the gas-exchange mechanism behind hypoxaemia in pulmonary contusion?

Blood and oedema fill the alveoli, so perfused but poorly ventilated lung causes shunt and V/Q mismatch.

Why is excessive IV fluid avoided in pulmonary contusion?

The injured capillaries leak, so fluid overload worsens alveolar oedema and hypoxaemia; resuscitate to normal perfusion only.

Which two late complications are the main concern after a large pulmonary contusion?

Pneumonia and ARDS.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: Pulmonary Contusion - Injuries; Poisoning - Merck Manual Professional Edition (Merck Manual Professional Edition, 2025); Pulmonary contusion and flail chest: an Eastern Association for the Surgery of Trauma practice management guideline (Journal of Trauma and Acute Care Surgery, 2012).

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