Lung Contusion (Bruised Lung)

What happens in a lung contusion

The lungs are spongy tissue made of millions of tiny air sacs (alveoli) surrounded by capillaries. When the chest wall is struck hard or compressed suddenly, a pressure wave passes through the lung and tears these small blood vessels. Blood and fluid then leak into the air sacs and the spaces between them.

Fluid-filled air sacs cannot exchange oxygen, so blood passing through the bruised area returns to the heart without picking up oxygen. Doctors call this a ventilation-perfusion mismatch. The bruised area also becomes stiffer, so breathing takes more effort. Inflammation spreads in the following day or two, which is why the contusion often looks and feels worse on day 2 than on the day of the injury.

Lung contusion is the most common lung injury in blunt chest trauma. It is found in a large share of people who have serious chest injuries, often alongside rib fractures. In children, whose ribs are more flexible, it can happen without any broken ribs.

Lung contusion symptoms

Symptoms may be mild at first and build over hours:

• Shortness of breath and a feeling of not getting enough air
• Chest pain, often from accompanying bruised or broken ribs, worse with deep breaths
• Coughing up blood or blood-streaked phlegm (hemoptysis)
• Fast breathing and a fast heart rate
• Low oxygen levels, sometimes with bluish lips or skin (cyanosis)
• Wheezing or crackles heard through a stethoscope
• Chest wall bruising, tenderness or a seatbelt mark

Small contusions may cause no symptoms and are found only on a CT scan. Large or both-sided contusions can cause severe breathing failure.

Causes

• Motor vehicle crashes, the leading cause, especially high-speed impacts and steering-wheel injuries
• Falls from height
• Crush injuries, such as being pinned under a vehicle
• Sports collisions and direct blows from a ball, helmet or knee
• Blast injuries from explosions, where the pressure wave damages the lungs
• Assaults, such as being kicked or stamped on

Injuries that often occur with it

Flail chest almost always has an underlying lung contusion, and the contusion usually causes more of the breathing trouble than the broken ribs themselves.

Diagnosis

Lung contusion is diagnosed in the ER as part of a trauma assessment.

• Physical exam: breathing rate, oxygen saturation, chest wall injuries and breath sounds.
• Pulse oximetry and arterial blood gas: measure how well oxygen is getting into the blood.
• Chest X-ray: shows patchy white areas, but often looks normal for the first 6 hours. It may underestimate the size.
• CT scan of the chest: the most accurate test. It shows contusions within minutes of injury and also detects rib fractures, pneumothorax and hemothorax.
• Lung ultrasound: used at the bedside in some trauma centers.
• ECG and heart tests if a cardiac contusion is suspected.

People with a sizeable contusion are usually admitted for monitoring because the lungs can deteriorate over the next day or two.

Treatment

There is no treatment that heals the bruise directly. Care supports breathing while the lung recovers on its own.

Supportive care

• Oxygen through nasal prongs or a mask to keep blood oxygen levels up.
• Pain control: good pain relief is vital so you can breathe deeply and cough. Options include acetaminophen (paracetamol), NSAIDs if safe, opioids, and nerve blocks or an epidural for multiple rib fractures.
• Breathing exercises: deep breathing, an incentive spirometer, and coughing (hugging a pillow against the chest) every hour while awake. These prevent collapse of the lung bases and pneumonia.
• Early mobilization: sitting up and walking as soon as safely possible.
• Careful IV fluids: too much fluid can worsen lung swelling, so doctors avoid overloading.

Severe contusions

• Non-invasive ventilation (a tight-fitting mask giving pressure support, such as CPAP or BiPAP).
• Mechanical ventilation through a breathing tube if oxygen levels stay low or breathing tires out.
• Surgical rib fixation for flail chest in selected people, which can shorten time on a ventilator.

Antibiotics and steroids are not given routinely. Antibiotics are used if pneumonia develops.

Complications

• Pneumonia: the most common complication, because bloody, collapsed lung tissue is easily infected
• Acute respiratory distress syndrome (ARDS): widespread lung inflammation causing severe breathing failure
• Respiratory failure needing a ventilator
• Long-term changes: a small number of people with large contusions have lasting breathlessness or scarring

Lung contusion recovery time

Most healthy people recover lung function completely. Exercise tolerance may be reduced for a few weeks. Return to contact sports is usually delayed until symptoms and any rib fractures have healed and a doctor has cleared you.

Frequently asked questions

What are the symptoms of a lung contusion?

The main symptoms are shortness of breath, chest pain, fast breathing and coughing up blood after a blow to the chest. Oxygen levels may drop. Symptoms often worsen over the first 24 to 72 hours, so anyone with breathing trouble after a chest injury should be assessed in an ER.

How long does a bruised lung take to heal?

A simple lung contusion usually improves within 3 to 5 days and clears on imaging in about a week. Associated broken ribs take 4 to 6 weeks. Severe contusions complicated by pneumonia or ARDS can take weeks to months.

Can a lung contusion heal on its own?

Yes. The body reabsorbs the blood and fluid over several days. Treatment supports breathing in the meantime with oxygen, pain relief and breathing exercises, and watches for complications such as pneumonia.

Is a lung contusion serious?

It can be. Small contusions heal without problems, but large ones can cause dangerously low oxygen levels, pneumonia or ARDS. Because symptoms can worsen after the first day, doctors usually observe people in the hospital.

Is a pulmonary contusion the same as a lung contusion?

Yes. Pulmonary contusion is the medical term, and bruised lung is the everyday term. All three describe bleeding and swelling in lung tissue after blunt chest trauma, without a tear in the lung.