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Slightly collapsed lung: Atelectasis – Symptoms and causes

Collapsed Lung (Atelectasis) | Cedars-Sinai





The lungs are like a pair of balloons inside the chest that fill up with air and then relax to let air leave the body. When a blockage occurs in the airway so the lung cannot fill up with air or if a hole or weakened place develops in the lung allowing air to escape, the lung can collapse like a balloon that has lost its air.


Symptoms of a collapsed lung vary. They may include:

  • Falling oxygen levels in the blood, which causes the person to look bluish or ashen and can bring on abnormal heart rhythms (arrhythmias)
  • Fever if an infection is present
  • Rapid, shallow breathing
  • Sharp pain on the affected side, if the symptoms are severe and the blockage occurred quickly
  • Shock with a severe drop in blood pressure and a rapid heart rate
  • Shortness of breath, which can be sudden and extreme in severe cases

If the blockages happen slowly, there may be few or no symptoms. Those that do occur may include shortness of breath, an increased heart rate or a hacking cough that does not seem to go away.

Causes and Risk Factors

A collapsed lung is often the result of pressure on an airway from outside – a swollen lymph node or fluid between the lining of the lungs and the chest wall, for example – can also cause a lung to collapse. 

When the airway is blocked, the blood absorbs the air inside the air sacs (alveoli). Without more air, the sac shrinks. The space where the lung was before the collapse fills up with blood cells, fluids and mucus. It may then become infected.

Other factors can lead to a collapsed lung include:

  • A plug of mucus, a tumor or something breathed into the lungs.
  • Abdominal swelling
  • Experiencing high speeds, such as being a fighter jet pilot
  • Injuries, such as from a car accident, a fall or a stabbing
  • Lack of the liquid (surfactant) that coats the lining of the alveoli, which helps keep it from collapsing. This can happen in premature babies or in adults who have had too much oxygen therapy or mechanical ventilation.
  • Large doses of opioids or sedatives
  • Lying immobilized in bed
  • Scarring and shrinking of the membranes that cover the lungs and line the inside of the chest, which can occur as a result of exposure to asbestos
  • Smoking
  • Surgery, especially involving the chest or abdomen
  • Tight bandages


To diagnose a collapsed lung, a physician conducts a physical examination and asks about symptoms and the setting in which they occurred. Other tests that may be performed include:

  • Bronchoscopy
  • Chest X-rays, which may or may not show the airless area of the lung
  • Computed tomography (CT), which can help identify an obstruction


There are several options for treating a collapsed lung. For example:

  • If the lung has collapsed because of a blockage, the blockage can be removed by coughing, suctioning the airways or bronchoscopy
  • Antibiotics can be given to treat an infection
  • Surgery to remove a part of the lung may be needed if chronic infections become disabling or if significant bleeding occurs
  • Surgery, radiation, chemotherapy or laser therapy may be used if a tumor is causing the blockage
  • Drugs to treat a lack of surfactant. This is a life-saving measure in newborns. In adults with acute respiratory distress syndrome, it is considered experimental. For adults, the amount of oxygen in the blood is raised by continuous positive-pressure oxygen or mechanical ventilation.


Preventing a collapsed lung is as important as treating one. These help avoid a collapsed lung:

  • Patients who smoke should stop six to eight weeks before surgery
  • After surgery, patients should breathe deeply, cough regularly and move about as soon as possible. Certain exercises, such as changing positions to help the lungs drain, or devices to encourage voluntary deep breathing (incentive spirometry) also help.
  • Patients with a deformed chest or nerve condition that causes shallow breathing might need help breathing. Continuous positive airway pressure delivers oxygen through the nose or a facemask. This ensures the airways do not collapse even during the pause between breaths. Sometimes a mechanical ventilator is needed.

© 2000-2022 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional’s instructions.

Collapsed lung (pneumothorax) Information | Mount Sinai

Air around the lung; Air outside the lung; Pneumothorax dropped lung; Spontaneous pneumothorax

A collapsed lung occurs when air escapes from the lung. The air then fills the space outside of the lung between the lung and chest wall. This buildup of air puts pressure on the lung, so it cannot expand as much as it normally does when you take a breath.

The medical name of this condition is pneumothorax.

The major features of the lungs include the bronchi, the bronchioles and the alveoli. The alveoli are the microscopic blood vessel-lined sacks in which oxygen and carbon dioxide gas are exchanged.

Aortic rupture (a tear in the aorta, which is the major artery coming from the heart) can be seen on a chest X-ray. In this case, it was caused by a traumatic perforation of the thoracic aorta. This is how the X-ray appears when the chest is full of blood (right-sided hemothorax) seen here as cloudiness on the left side of the picture.

Pneumothorax occurs when air leaks from inside of the lung to the space between the lung and the chest wall. The lung then collapses. The dark side of the chest (right side of the picture) is filled with air that is outside of the lung tissue.

Air is breathed in through the nasal passageways, travels through the trachea and bronchi to the lungs.

The pleural cavity is the space between the layers of the membrane lining the lung (pleura) and the chest cavity.

The lungs are paired organs that lie in the thoracic cavity. The lungs extract oxygen from inhaled air and transport the oxygen to the blood. Surrounding the lungs is a very thin space called the pleural space. The pleural space is usually extremely thin, and filled with a small amount of fluid.


Collapsed lung can be caused by an injury to the lung. Injuries can include a gunshot or knife wound to the chest, rib fracture, or certain medical procedures.

In some cases, a collapsed lung is caused by air blisters of the lung (blebs) that break open, sending air into the space around the lung. This can result from air pressure changes such as when scuba diving or traveling to a high altitude.

Tall, thin people and smokers are more at risk for a collapsed lung.

Lung diseases can also increase the chance of getting a collapsed lung. These include:

  • Asthma
  • Chronic obstructive pulmonary disease (COPD)
  • Cystic fibrosis
  • Tuberculosis
  • Whooping cough

In some cases, a collapsed lung occurs without any cause. This is called a spontaneous collapsed lung or spontaneous pneumothorax.


Common symptoms of a collapsed lung include:

  • Sharp chest or shoulder pain, made worse by a deep breath or a cough
  • Shortness of breath
  • Nasal flaring (from shortness of breath)

A larger pneumothorax causes more severe symptoms, including:

  • Bluish color of the skin due to lack of oxygen
  • Chest tightness
  • Lightheadedness and near fainting
  • Easy fatigue
  • Abnormal breathing patterns or increased effort of breathing
  • Rapid heart rate
  • Shock and collapse

Exams and Tests

The health care provider will listen to your breathing with a stethoscope. If you have a collapsed lung, there are decreased breath sounds or no breath sounds on the affected side. You may also have low blood pressure.

Tests that may be ordered include:

  • Chest x-ray
  • Arterial blood gases and other blood tests
  • CT scan if other injuries or conditions are suspected
  • Electrocardiogram (ECG)


A small pneumothorax may go away on its own over time. You may only need oxygen treatment and rest.

The provider may use a needle to allow the air to escape from around the lung so it can expand more fully. You may be allowed to go home if you live near the hospital.

If you have a large pneumothorax, a chest tube will be placed between the ribs into the space around the lungs to help drain the air and allow the lung to re-expand. The chest tube may be left in place for several days and you may need to stay in the hospital. If a small chest tube or flutter valve is used, you may be able to go home. You will need to return to the hospital to have the tube or valve removed.

Some people with a collapsed lung need extra oxygen.

Lung surgery may be needed to treat collapsed lung or to prevent future episodes. The area where the leak occurred may be repaired. Sometimes, a special chemical is placed into the area of the collapsed lung. This chemical causes a scar to form. This procedure is called pleurodesis.

Outlook (Prognosis)

If you have a spontaneous collapsed lung, you are more likely to have another one in the future if you:

  • Are tall and thin
  • Continue to smoke
  • Have had two collapsed lung episodes in the past

How well you do after having a collapsed lung depends on what caused it.

Possible Complications

Complications may include any of the following:

  • Another collapsed lung in the future
  • Shock, if there are serious injuries or infection, severe inflammation, or fluid in the lung develops

When to Contact a Medical Professional

Contact your provider if you have symptoms of a collapsed lung, especially if you have had one before.


There is no known way to prevent a collapsed lung. Following standard procedure can reduce the risk of a pneumothorax when scuba diving. You can decrease your risk by not smoking.

Hallifax R, Rahman NM. Pneumothorax. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel’s Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 110.

Peak DA. Scuba diving and dysbarism. In: Walls RM, ed. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 131.

Raja AS. Thoracic trauma. In: Walls RM, ed. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 37.

Last reviewed on: 1/2/2023

Reviewed by: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Pneumothorax: causes, symptoms and recommendations for the treatment of the disease. Dr. Peter

The lungs are covered on the outside with a smooth organ membrane – the visceral pleura. Another thin layer of tissue, the parietal pleura, lines the inside of the chest wall. Both layers of the pleura are separated from each other by a narrow, fluid-filled space – the pleural cavity. A certain negative pressure arises in the pleural cavity, which allows the so-called adhesive forces to literally attract the visceral and parietal parts of the pleura to each other. With this mechanism, the lungs follow the movements of the chest with each breath. If air enters the pleural cavity, the forces of physical cohesion are eliminated. The lung fails to expand in the affected area when inhaled and instead collapses (collapsed lung). In some cases, however, so little air enters the pleural cavity that the patient hardly notices anything.

Depending on the origin of the trapped air, doctors distinguish between internal and external pneumothorax:

  • Open pneumothorax : air enters the pleural cavity from the outside, accumulating between the chest wall and the lungs – for example, in the event of an accident, when something pierces chest.

  • Closed pneumothorax : when air enters the pleural cavity through the respiratory tract, for which there can be several reasons. Internal pneumothorax is more common than external pneumothorax.

Pneumothorax can also be classified according to the degree of air intake: if there is very little air in the pleural cavity, doctors speak of mantle pneumothorax. The lungs are still severely stretched, so it is possible that the victim has little to no symptoms.

But in the case of pneumothorax with collapsed lung, most of the organ collapses (partially), causing severe symptoms.

A serious complication of pneumothorax is the so-called tension (valvular) pneumothorax. It occurs in about 3% of cases of pneumothorax. With tension pneumothorax, more air is forced into the pleural cavity with each breath, but it cannot exit. As a result, the air in the chest takes up more and more space – it gradually compresses previously unaffected areas of the lungs, as well as large veins leading to the heart.


Depending on the cause, doctors distinguish different forms of pneumothorax:

  • Primary spontaneous pneumothorax : usually occurs unexpectedly in healthy people, especially in young, slender men. The cause is spontaneous rupture of the lung tissue, for example, when emphysema bubbles suddenly burst in the lung tissue near the lung membrane. These bubbles form from the air sacs (alveoli) in the lungs when the walls between the individual sacs collapse (mostly from smoking!). However, if the exact cause remains unclear, it is called idiopathic spontaneous pneumothorax.

  • Secondary spontaneous pneumothorax : develops in the presence of an existing lung disease. In most cases, this is COPD (chronic obstructive pulmonary disease), less often other diseases, such as pneumonia.

  • Traumatic pneumothorax : caused by trauma to the chest. For example, the intense pressure from a car accident can break ribs and damage the lungs. Then air can penetrate from the outside into the pleural cavity. Stab wounds to the chest can also cause traumatic pneumothorax.

  • Iatrogenic pneumothorax : this is when the pathology is the result of a medical intervention. For example, chest compressions used to resuscitate a cardiac arrest can break ribs and damage the lungs – followed by pneumothorax. When tissue is removed from the lungs (lung biopsy), bronchoscopy, or when a central venous catheter is placed, air can inadvertently enter the pleural space.

  • Tension pneumothorax (also: valvular pneumothorax) may develop as a possible complication of pneumothorax. The valve mechanism is created at the point where air enters the pleural cavity – with each breath, new air enters without escaping. The resulting excess pressure in the pleural cavity shifts the heart to the healthy side, and also causes narrowing of the intact lung and large vessels. In the worst case, the pumping ability of the heart is so impaired that circulatory failure occurs – there is a risk of death!

An important risk factor for primary spontaneous pneumothorax is smoking — About 90% of all patients with pneumothorax smoke.

Women generally have a lower risk of spontaneous pneumothorax than men. However, in certain situations they are more susceptible to it. In childbearing age, the so-called menstrual pneumothorax can occur within 72 hours before or after menstruation. It usually happens on the right side. The cause of this special form of pneumothorax has not yet been elucidated. Endometriosis (when the lining of the uterus settles in the chest area) can be a trigger, or air can enter the abdomen through the uterus and from there into the chest. Catamenial pneumothorax is very rare, but has a high risk of recurrence. Another particular case is pneumothorax during pregnancy.

Symptoms of pneumothorax

Pneumothorax presents with a variety of symptoms depending on the cause and severity. If there is very little air in the pleural cavity (mantle pneumothorax), the victim may not have any symptoms at all.

But pneumothorax with collapsed lung and large air intake is a dangerous condition, which is usually accompanied by clear symptoms:

  • Severe cough.

  • Stitching, breathing-dependent pain in the affected side of the chest.

  • Possible formation of air bubbles under the skin (skin emphysema).

  • Asymmetric movement of the chest during breathing (“lag” of the affected side).

  • In so-called menstrual pneumothorax, which occurs in young women during the premenstrual period, chest pain and shortness of breath are usually accompanied by expectoration of bloody discharge (hemoptysis).

    With tension pneumothorax, shortness of breath continues to increase. If the lungs can no longer absorb enough oxygen to supply the body, the skin and mucous membranes turn blue (cyanosis). The heartbeat is even and strongly accelerated. In case of tension pneumothorax, it is necessary to consult a doctor as soon as possible!

    Possible Complications and Risks

    The course of a pneumothorax depends on its cause and the type and extent of any causative injury. The prognosis for the most common form, spontaneous pneumothorax, is usually good. The body can often gradually absorb a small amount of air from the pleural cavity (mantle pneumothorax), so that the pathology resolves itself.

    If the lung has collapsed, treatment with pleural drainage or surgery is necessary. After the procedure, people usually recover quickly. However, in a third of patients with spontaneous pneumothorax, air again enters the pleural cavity (relapse). The best prevention is surgery (pleurodesis).

    In addition, victims should avoid diving due to pressure fluctuations and should preferably stop smoking, both of which reduce the risk of recurrence. Patients with large foci of emphysema should also exercise caution when flying and consult with a physician beforehand if necessary.

    In the case of traumatic pneumothorax, the prognosis depends on damage to the lung and/or pleura. Severe injuries after an accident can be life threatening.

    Tension pneumothorax must always be treated immediately or death is likely.


    First of all, the doctor will ask about the medical history (medical history): he will ask about the type and severity of symptoms, the time of their onset and any previous incidents, as well as existing lung diseases. You should also tell your doctor about any medical interventions or injuries in the chest area.

    After the conversation, a physical examination is performed: the doctor listens to the heart and lungs with a stethoscope – in pneumothorax, the breath noise in the affected lung is usually much weaker. He also taps on his chest and listens to see if the sound of tapping has changed in certain places.

    If a pneumothorax is suspected, a chest x-ray is taken as soon as possible. In most cases, some characteristic signs can be revealed on the x-ray: in addition to the accumulation of air in the pleural cavity, sometimes a lung collapse can also be seen on the x-ray.

    If x-rays are inconclusive, additional tests may be needed, such as ultrasound, computed tomography, or puncture of the suspicious area (pleural puncture).

    How to treat pneumothorax

    Treatment of pneumothorax initially depends on its exact characteristics. If there is little air in the pleural space (mantle pneumothorax) and no severe symptoms, the pneumothorax can often resolve completely without treatment. In this case, the person initially remains under medical supervision to monitor the further course of the disease. Regular clinical examinations and x-ray checks help.

    Pleural drainage and pleurodesis

    If the lung has collapsed, pleural drainage becomes the treatment of choice: the doctor inserts a drainage tube from the outside through the chest into the pleural cavity. In pneumothorax, this usually occurs through the second intercostal space from above (Monaldi drainage). The doctor can now gently aspirate air from the pleural cavity through the tube and thereby restore negative pressure.

    In an emergency, especially in cases of tension pneumothorax after an accident, the doctor may puncture the pleural cavity with a lung relief cannula so that the trapped air can escape. Later, drainage of the pleural cavity follows.

    If there is a risk of a pneumothorax coming back, doctors sometimes perform a special operation called pleurodesis. This procedure is performed as part of a thoracoscopy – endoscopy of the chest cavity: the lung and pleura are “glued” together (i.