What Is Catamenial Pneumothorax?

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Catamenial pneumothorax is a rare condition of the membranes surrounding the lungs. It only occurs in people who have a menstrual cycle. Pneumothorax refers to the presence of air in the space between the lungs and the wall of the chest (pleura), which causes one or both lungs to collapse. "Catamenial" is a medical term used to designate signs, symptoms, or conditions that only occur when a person is having a menstrual period.

Female patient receiving MRI scan
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Catamenial Pneumothorax Symptoms

The major indication that someone is experiencing pneumothorax is sudden chest pain, which can be quite severe if the lung has collapsed.

Other signs and symptoms of pneumothorax include:

People who have catamenial pneumothorax often have a specific pattern to their symptoms which can help differentiate the condition from pneumothorax caused by something else.

Additional symptoms associated with catamenial pneumothorax include:

  • Dry cough
  • Dizziness and fatigue
  • Crackling sound when taking a breath
  • Lung collapse within 72 hours of the onset of a menstrual period
  • Recurrent episodes of pneumothorax that happen monthly or in conjunction with a person's menstrual cycle
  • Chest pain that comes and goes on a monthly basis in accordance with the menstrual cycle, which may be worse on one side than the other (the right side is most commonly affected)


Pneumothorax is often caused by an injury or trauma to the chest, like what a person might sustain in a car accident. Pneumothorax can also occur spontaneously (without an obvious cause). The exact cause of catamenial pneumothorax is unknown.


Many documented cases of catamenial pneumothorax occurred in people with endometriosis. In this condition, a type of tissue that is similar to the lining of the uterus (which is shed during a period) becomes implanted in other parts of the body.

The tissue is most often found in the organs closest to the uterus, such as the fallopian tubes, ovaries, and the pelvic cavity, but can occur elsewhere—including the chest cavity.

No matter where this tissue becomes implanted, it responds to the body's hormonal cues the same way as the lining of the uterus—meaning it bleeds each month. Unlike tissue found in the uterus, the blood from these extra-uterine lesions cannot leave the body. Instead, it causes inflammation and scarring.

Catamenial pneumothorax is believed to be caused when lesions of endometriosis become implanted in the pleura of the chest. When a person has a menstrual period, the tissue bleeds and forms cysts in the thoracic cavity. When blood, rather than air, leaks into the space between the chest wall and the lungs, the condition is referred to as hemothorax.

If a person has a history of endometriosis or has had prior surgery for the condition, the diagnosis of catamenial pneumothorax may be easier to make. Unfortunately, endometriosis can also be very difficult to diagnose.

A person may not realize they have endometriosis even if they are experiencing symptoms suggestive of it. Some people with endometriosis do not experience symptoms. Others may not know what endometriosis is or do not realize the symptoms they experience, especially those related to their menstrual cycle, are not normal.

If a person develops a spontaneous pneumothorax, especially if it happens more than once and always around the time of their period, it may lead to a diagnosis of endometriosis. However, cases of catamenial pneumothorax have also been diagnosed in people who do not have endometriosis.

Other Theories

A few other theories have been suggested that could explain what causes a person to develop catamenial pneumothorax. It's been observed that prostaglandins, a type of hormone essential for ovulation, may cause changes in the bronchioles of the lungs. It may be that constriction of the bronchioles at certain points during the menstrual cycle can contribute to the development of pneumothorax.

Other researchers have postulated that blebs, small pustules that can appear on the lungs, may burst in response to changes in hormone levels throughout the menstrual cycle. When blebs rupture, the blood that escapes may find its way into the pleural space and cause symptoms.

It has also been suggested that as the reproductive organs allow for the flow of menstrual effluent, air may be released and find its pelvis into the chest cavity via the diaphragm.


Catamenial pneumothorax typically occurs in females of reproductive age. It is not known how common the condition is in the general population, as many cases likely go undiagnosed. Still, catamenial pneumothorax is considered to be rare. Interestingly, it seems to happen most frequently on the right side of the chest, though the reason for this is not clear.

Correctly diagnosing catamenial pneumothorax can be difficult. Certain signs or symptoms, such as respiratory symptoms or lung collapse that recur during the menstrual cycle, may make a doctor suspect catamenial pneumothorax.

Many people who are ultimately diagnosed with catamenial pneumothorax are first diagnosed with a spontaneous collapsed lung. If you have symptoms of a collapsed lung, you may be evaluated at the hospital, clinic, or in your regular doctor's office.

History and Physical Examination

Your doctor will evaluate your condition in several ways. They will start by asking you questions about your current symptoms, as well as how your health has been in the past. They may also ask you about any health problems that run in your family. This is referred to as taking a patient history.

You may be asked questions about your lifestyle, such as if you smoke, drink, and get regular exercise. You will likely be asked about any medications you take, including over-the-counter medicine, vitamins, or health supplements.

Sometimes, you may be asked the same questions by more than one healthcare provider while you are being treated or may be asked to review the information that is already in your medical record to make sure it is correct and up to date.

A nurse or doctor will also check your vital signs, taking your temperature, measuring your pulse and blood pressure, and asking you to rate any pain you are feeling on a numerical scale.

If the doctor needs to do a physical exam or order certain kinds of tests, you may be asked to change into a hospital gown. During a physical exam, your doctor may place a stethoscope on your chest or back to listen to your breath or use their hands to feel your belly. Let them know if you experience pain as they perform the exam.

Laboratory Tests

Other types of tests may be needed to investigate your symptoms. You may be asked to provide a urine or stool sample, which can help doctors rule out infections or conditions.

A nurse or lab technician may use a needle to take a sample of your blood. Some people with catamenial pneumothorax have elevated levels of a protein called CA-125, though this does not always occur. Abnormal levels of CA-125 can happen due to other conditions. If you have higher-than-normal levels, it doesn't mean you definitely have a catamenial pneumothorax. Likewise, having normal levels of CA-125 doesn't rule out the possibility of the condition.

Even though a blood test might not help diagnose catamenial pneumothorax, it can help your doctor eliminate other diseases or conditions that cause similar symptoms.


Your doctor might send you to the radiology department to have an imaging test, such as a computerized tomography (CT) scan, magnetic resonance imaging (MRI), or ultrasound. In some cases, the doctor who looks at the results of imaging tests (radiologist) may see signs of catamenial pneumothorax, but most often these images help rule out other causes for your symptoms, such as injuries, tumors, or blood clots.


If your doctor suspects catamenial pneumothorax but wants to be sure of the diagnosis, they may recommend you have a minimally-invasive procedure called video-assisted thoracoscopy (VAT), which uses a small camera to look inside your chest cavity. During the procedure, the surgeon may be able to see lesions or blood.

They will also take a small tissue sample to be tested (biopsy). The doctor who tests the tissue (pathologist) can tell if it is endometrial-like tissue which, when found on the lungs or diaphragm, can confirm a person has catamenial pneumothorax caused by thoracic endometriosis.


There are currently no established guidelines for definitively treating catamenial pneumothorax, but there are several options available. In most cases, a combination of treatments is required to manage the condition.

Many people who experience catamenial pneumothorax often have minor episodes that seem to get better on their own without treatment. However, if a person doesn't seek treatment when they are having symptoms, the condition may become more serious over time.

Not seeking treatment also allows the underlying condition causing catamenial pneumothorax, such as endometriosis, to get worse. Even if endometriosis doesn't progress to life-threatening complications, the condition can seriously impact a person's quality of life.

Emergency Treatment

If a person develops an acute pneumothorax, they need emergency medical care. When the condition becomes chronic, as can happen with catamenial pneumothorax, the treatment will depend on the underlying cause and may not always require emergency medical intervention.

A tension pneumothorax, or a collapsed lung that presses on structures surrounding the heart, is a medical emergency and can be fatal without treatment. In an emergency, the treatment for a pneumothorax may involve the insertion of a tube in the chest to free any trapped air or blood (aspiration). While effective at resolving the problem, chest tubes have risks and can lead to complications, so close medical follow-up is important.

When a person is stable enough to have more tests, doctors will try to determine why the pneumothorax occurred. If a person is diagnosed with catamenial pneumothorax, doctors that specifically treat reproductive health conditions (obstetrician/gynecologists and surgeons) will likely be consulted to discuss potential treatment options.

Endometriosis Treatment

If a catamenial pneumothorax is caused by a hormonally-driven condition like endometriosis, one of the first treatments a healthcare provider may recommend is hormonal therapy.

Options like continuous birth control pills or GnRH antagonists (such as Lupron) can be used to suppress a person's menstrual cycle to control symptoms. However, it should be noted that medications such as Lupron are not intended to be used long-term. Additionally, some people cannot safely take hormonal birth control pills due to underlying conditions that heighten their risk of blood clots.

If you are unable to take medication, or if it does not work for you, your doctor may recommend you have surgery. If a catamenial pneumothorax is linked to endometriosis, surgery may be the preferred treatment, as it allows a surgeon to remove any lesions or blood in the chest cavity, as well as look at other areas endometriosis is commonly found, such as the abdomen and pelvis.

Surgery can often be done laparoscopically. During a procedure, the surgeon will make a few small incisions in your belly through which they can insert the tools they need to explore as well as a small camera to help them see inside your body.

Compared to open surgery, people usually heal quicker and have fewer complications with laparoscopic surgery. However, if a person's case is complicated, a surgeon may have to use traditional open surgery methods instead.

If a person has many lesions or the structures are damaged, parts of the diaphragm or lung may need to be removed (resected). A person may need to have more than one surgery to manage the condition.

Pleurodesis and Pleural Abrasion

Another intervention that focuses on the diaphragm is called pleurodesis. In this treatment, a person may be given medication to cause inflammation in the lining of the chest cavity (pleura). The body responds to inflammation by creating scar tissue which covers up any holes that may have formed, allowing blood to get into space.

If the medication does not cause enough inflammation, a person may need to have a surgical procedure called pleural abrasion, where the surgeon rubs the inside of the chest cavity to directly cause inflammation. A surgeon may also put a type of dissolvable surgical mesh on the tissue of the diaphragm to help cover up any holes.

If you decide to have surgery, your medical team will discuss these possibilities with you and make sure you understand the risks and benefits.

A Word From Verywell

Catamenial pneumothorax is a rare condition affecting people who have a menstrual cycle. While the condition is uncommon, without treatment it can have serious consequences and seriously impact a person's quality of life. Diagnosing catamenial pneumothorax can be tricky, but it is usually suspected when a person experiences respiratory symptoms that sync up with their menstrual cycle. The treatment will depend on the underlying cause of the condition but generally is limited to hormonal therapy, surgery, or both.

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Additional Reading
  • Peikert T, Gillespie DJ, Cassivi SD. Catamenial pneumothoraxMayo Clinic Proceedings. 2005;80(5):677-680. doi:10.4065/80.5.677