Introduction

Most people have heard of a collapsed lung, but few know that it can be linked to the menstrual cycle. This rare condition, known as catamenial pneumothorax (CP), accounts for around 3-6%¹ of spontaneous pneumothorax cases in menstruating women. It involves a recurrent lung collapse that happens within 72 hours before or after the onset of period.² While rare, its impact can be life-changing for those affected.

Over 90% of cases occur on the right lung,³ and many are associated with thoracic endometriosis syndrome,⁴ which is a condition where tissue similar to the lining of the uterus grows inside the chest cavity. This could cause small defects in the diaphragm or can weaken lung tissue, creating a path for air to leak into the pleural space and cause lung collapse. Symptoms could include: sudden chest pain, shortness of breath, and coughing.⁵

Unfortunately, CP is quite often misdiagnosed, leading to repeated pneumothorax and delayed treatments. Studies showed that chest tube drainage, the standard treatment for lung collapses, carries a recurrence rate of up to 50% in this condition.⁶ Because of this, doctors are increasingly using video-assisted thoracoscopic surgery (VATS), which is a minimally invasive approach that allows them to look at the chest cavity, repair diaphragm defects and perform pleurodesis,⁷ which can reduce the chance of recurrence.

This article will explore the science behind catamenial pneumothorax, review surgical options such as VATS and pleurodesis, and provide practical information for women navigating this often misunderstood condition.

Diagnosis

It can be hard to recognise catamenial pneumothorax (CP) because symptoms are often very similar to those of other lung collapse cases. This leads to women going through repeated episodes before receiving the right diagnosis. The key aspect is the timing of symptoms: CP usually occurs within 72 hours before or after menstruation begins.² Symptoms often present as sudden chest pain, shortness of breath, or shoulder pain, recurring month after month.³ Because these manifestations are similar to other lung conditions, doctors need a higher level of suspicion to make connections with the menstrual cycle.

The first step in diagnosis is chest imaging in the form of a chest X-ray, which looks at whether a pneumothorax (air in the plural space causing a lung collapse) is present. In some cases, a CT or MRI may reveal smaller features such as small holes in the diaphragm or suspicious tissue implants.⁴

However, the best option for diagnosis is video-assisted thoracoscopic surgery (VATS). This is a minimally invasive procedure which allows doctors to look inside the chest cavity but also provides an opportunity to identify defects in the diaphragm, lung blebs or endometrial implants that may go unnoticed.⁸ Tissue samples which are taken during VATS can be examined under a microscope to identify endometriosis, making it both a diagnostic and therapeutic tool.⁹

Because CP is a rare condition, many women are misdiagnosed or treated solely with a standard chest tube, which generally has a recurrence rate of up to 50%.⁶ A thorough diagnosis is therefore critical to ensure the right surgical and medical management, reducing the risk of repeated episodes.

Surgical management (VATS and pleurodesis)

Surgery offers the most effective long-term results for the treatment of CP. Recurrence rates remain high when a regular chest tube is used to fix the lung collapse.⁶ Because of this, many thoracic surgeons recommend Video-Assisted Thoracoscopic Surgery (VATS) combined with pleurodesis as the treatment of choice.

Video-Assisted Thoracoscopic Surgery (VATS)

VATS is a modern, less invasive surgical approach in which small incisions are made in the chest wall. It allows a tiny camera and instruments to be inserted through these openings. This allows surgeons to gain a detailed view of the pleural cavity and the diaphragm. In CP patients, VATS is especially useful because it enables surgeons to:

• Identify and repair diaphragmatic defects, often small holes through which air can pass¹⁰
• Resect visible endometrial implants from the pleura or diaphragm¹¹
• Remove lung blebs or bullae that may contribute to pneumothorax¹²

According to studies, patients who undergo VATS with diaphragmatic repair experience significantly lower recurrence rates compared to those treated with just chest tube drainage.¹³

Pleurodesis

To prevent the lung from collapsing again, another treatment called pleurodesis is used. In this treatment, the parietal pleura (inner lining of the chest wall) is intentionally irritated during surgery, so that the lungs stick more easily to it. It’s done either mechanically (using abrasion) or chemically (using substances such as talc). This means the lungs stick to the chest wall, eliminating the pleural space where air could gather and cause another collapse.¹⁴

In CP, pleurodesis is often performed alongside VATS. Research has found that combining diaphragmatic repair, pleurectomy, and pleurodesis can lower recurrence rates to 8-12%.¹⁵ Although no single treatment guarantees that the risk of recurrence is eliminated, this approach remains the most reliable for long-term management.

Combined surgical-hormonal approach

Some surgeons recommend adding postoperative hormonal therapy such as Gonadotropin-releasing hormone (GnRH) analogues, to suppress menstruation and reduce recurrence further.¹⁶ However, surgical intervention remains central, as hormonal therapy alone does not address existing defects or endometrial implants.

In summary, VATS with pleurodesis and diaphragmatic repair offers the best balance of effectiveness and safety, making it the cornerstone of surgical management for catamenial pneumothorax.

Risks, complications and considerations

VATS with pleurodesis and diaphragmatic repair is considered the most effective treatment for CP. However, as with most surgeries, there are risks and factors that patients and clinicians must carefully observe.

Surgical risks

VATS generally has fewer complications compared to open thoracotomy since it is a minimally invasive surgery, but some risks remain. These include:

• Bleeding and infection at the surgical site¹⁷
• Air leaks, which may lengthen chest tube drainage and hospital stay¹⁸
• Postoperative pain, typically less than after open surgery¹⁹
• Damage to surrounding structures, such as the diaphragm or phrenic nerve, though this is rare²⁰

Pleurodesis-related complications

Both types of pleurodesis can cause chest pain or discomfort, fever or temporary inflammation.²¹ Rarely, chemical pleurodesis agents can trigger respiratory complications, though this is rare with modern treatments.²²

Recurrence despite surgery

After surgery, recurrence can still happen. Recurrence rates differ, with studies suggesting 8-25% depending on the surgical technique used. It also depends on whether thoracic endometriosis is present and if diaphragmatic defects are repaired.^15,23 The risk of a further lung collapse is also higher if suspicious endometrial implants are missed during the surgery, or if only pleurodesis is carried out.²⁴

Hormonal therapy considerations

Doctors will balance out recurrence prevention with side effects when deciding to use hormonal therapy after surgery. Prolonged use of hormones such as GnRH analogues can cause hot flashes, bone density reduction, or mood changes.²⁵ Therefore, hormonal therapy is used for a limited time or only in women with confirmed thoracic endometriosis.

Multidisciplinary approach

Because CP lies at the intersection of thoracic surgery and gynaecology, a multidisciplinary team is crucial. Thoracic surgeons, gynaecologists, and pulmonologists can collaborate to tailor treatment, manage fertility concerns, and plan long-term follow-up.²⁶ This team-based approach helps ensure that both the pulmonary and gynaecological aspects of CP are addressed.

In short. While surgery provides the best long-term control of CP, patients must be informed of potential risks, recurrence, and the role of hormonal therapy. The most successful outcomes come from individualised care and coordinated, multidisciplinary management.

FAQs

What exactly is catamenial pneumothorax?

Catamenial pneumothorax (CP) is a rare condition where a woman’s lung collapses around the time of her menstrual period. It is linked to thoracic endometriosis, where tissue similar to the uterine lining grows in the chest, affecting the diaphragm and lungs.^1,7

How is CP diagnosed?

Diagnosis usually involves imaging (X-ray, CT scan, MRI) to confirm lung collapse, but a definitive diagnosis often requires VATS (Video-assisted thoracoscopic surgery). VATS allows doctors to directly see and treat lesions on the lung and diaphragm.¹²

What is VATS, and how does it help?

VATS is a minimally invasive surgical technique where small instruments and a camera are inserted into the chest. Surgeons can then repair the diaphragm, remove endometrial implants, and perform pleurodesis (causing the lung lining to stick together to prevent future collapse).^14,15

What is pleurodesis?

Pleurodesis is a procedure that makes the lung lining stick to the chest wall so the lung cannot collapse again. It can be done mechanically (rubbing the pleura) or chemically (using substances like talc). When combined with diaphragmatic repair, it significantly reduces recurrence rates.^21,23

Can CP come back after surgery?

Yes, recurrence is possible even after surgery. Recurrence rates range from 8-25%, depending on surgical technique, hormonal treatment, and follow-up.^23,24 The risk is lowest when surgery is combined with hormonal suppression therapy.²⁵

Does CP mean I cannot get pregnant?

No, CP itself does not prevent pregnancy. However, since it is linked to endometriosis, some women may experience fertility challenges. A multidisciplinary approach with both thoracic surgeons and gynaecologists helps balance treatment and fertility goals.^26,27

Is CP life-threatening?

While a single pneumothorax is rarely fatal, repeated lung collapses can be dangerous if untreated. Surgery is strongly recommended to prevent complications and improve quality of life.^18,23

Summary

Catamenial pneumothorax (CP) is a rare condition where someone’s lung collapses around the time of their period, due to being linked to thoracic endometriosis. CP is often misdiagnosed, leading many to struggle with this condition for years before receiving treatment.

Video-assisted thoracoscopic surgery (VATS) is the most effective treatment and is often combined with pleurodesis and repair of diaphragmatic defects. These procedures greatly lower the risk of recurrence. However, note that CP may still come back in some patients depending on what technique was used.

In short, while CP is a rare condition, advances in surgical management such as VATS and pleurodesis have made it far more treatable, giving patients hope for long-term relief and better quality of life.