What is catamenial pneumothorax?
A pneumothorax is a collapsed lung, caused by air leaking into the space between the lung and the chest wall. Catamenial pneumothorax is a rare type that occurs in women of reproductive age and recurs in relation to menstruation, typically from the day before a period starts to about three days after.
It is the most common form of thoracic endometriosis syndrome, a group of conditions in which tissue similar to the lining of the womb is found in the chest: on the diaphragm, the pleura or, less often, the lung itself. Other forms include bleeding into the chest (catamenial haemothorax), coughing up blood with periods, and lung nodules.
The condition is under-recognised. Many women have several episodes before the link with their cycle is noticed, so asking about the timing of each collapse is an important part of assessing any woman with a pleural problem.
Symptoms
The symptoms are those of any pneumothorax, but with a monthly pattern:
- Sudden chest pain: usually sharp, on one side, often worse on breathing in.
- Breathlessness: ranging from mild to severe, depending on the size of the collapse.
- Shoulder or upper abdominal pain: from irritation of the diaphragm, sometimes felt under the right ribs or at the tip of the shoulder.
- Recurrence: repeated episodes clustered around periods.
The right side is affected in the great majority of cases. Many women also have pelvic endometriosis, with painful periods, pelvic pain or difficulty conceiving, although the chest symptoms sometimes appear first.
Causes and risk factors
Several mechanisms probably contribute, and more than one may be present in the same patient:
- Diaphragmatic defects: small holes in the diaphragm, often caused by endometriosis, through which air from the abdomen can pass into the chest during menstruation.
- Pleural and lung endometriosis: deposits that break down and bleed with the menstrual cycle, creating small air leaks from the lung surface.
- Hormonal effects: prostaglandins released during menstruation may cause small airways and vessels to constrict, contributing to alveolar rupture.
Risk factors include pelvic endometriosis and previous pelvic surgery, and the condition usually appears in the thirties and forties. Other causes of recurrent pneumothorax in women, such as lymphangioleiomyomatosis and Birt-Hogg-Dube syndrome, are considered at the same time.
How catamenial pneumothorax is diagnosed
The diagnosis is first suspected from the timing of episodes. A simple menstrual diary recorded alongside each episode is very helpful.
| Test | What it shows |
|---|---|
| Chest X-ray | Confirms the pneumothorax and its size |
| CT chest | Excludes lung cysts or other causes, and may show nodules or diaphragmatic changes |
| MRI of chest and diaphragm | Can detect endometriosis deposits, particularly if timed with the cycle |
| Pelvic ultrasound or MRI | Looks for pelvic endometriosis |
| Video-assisted thoracoscopic surgery (VATS) | Direct inspection of the diaphragm and pleura for holes and endometrial deposits, with biopsy |
| Histology | Confirms endometrial tissue in samples taken at surgery |
A negative biopsy does not exclude the condition, because deposits are small and easily missed. The diagnosis is often made on the combination of timing and surgical findings.
Treatment
Treating the acute episode
A small pneumothorax with few symptoms may be observed. Larger or symptomatic collapses are treated with needle aspiration or a chest drain, following standard pneumothorax guidance.
Surgery
Because recurrence is common with drainage alone, surgery is usually advised once the diagnosis is suspected. Video-assisted thoracoscopic surgery allows the surgeon to inspect the whole diaphragm, repair or remove the affected portion, sometimes reinforce it with mesh, remove visible deposits and perform pleurodesis, a procedure that makes the lung adhere to the chest wall so that it cannot collapse again. Surgery is ideally timed during menstruation, when deposits are easiest to see. These procedures are planned with a thoracic surgeon.
Hormonal treatment
Hormonal suppression after surgery substantially lowers the chance of recurrence. Options include GnRH agonists for a period of months, progestogens such as dienogest, and continuous combined oral contraceptives. The choice is made with a gynaecologist, taking into account pelvic endometriosis, side effects and plans for pregnancy.
Outlook and follow-up
Recurrence is more frequent than with ordinary spontaneous pneumothorax, even after surgery, so long-term follow-up with joint care between the chest and gynaecology teams is important. Most women achieve good control with surgery followed by hormonal treatment. Pregnancy is generally possible. Hormonal suppression is paused when trying to conceive, and recurrence risk is discussed in advance. The condition usually settles after the menopause. Women should not fly until a pneumothorax has fully resolved and been confirmed on X-ray.
When to seek urgent care
Go to an emergency department immediately for sudden chest pain with breathlessness, breathlessness at rest, a racing heart, lightheadedness or blue lips. A tension pneumothorax, though uncommon, is life-threatening. Women known to have the condition should seek same-day assessment for any new chest pain around a period rather than waiting for it to pass.
Frequently asked questions
How do I know if my collapsed lung is linked to my periods?
The main clue is timing. Catamenial pneumothorax typically occurs from the day before a period starts to about three days after, and tends to recur. Recording the date of each episode alongside your menstrual cycle helps your doctor make the connection.
Do I have endometriosis if I have catamenial pneumothorax?
Most women with catamenial pneumothorax have endometriosis in the chest, the pelvis or both, although it is not always proven on biopsy. Assessment by a gynaecologist is usually part of care.
Is surgery always necessary?
Surgery is usually recommended because the risk of recurrence is high with chest drainage alone. It allows the diaphragm to be repaired and pleurodesis to be performed. Hormonal treatment afterwards further reduces recurrence.
Can I become pregnant after treatment?
Yes, in most cases. Hormonal suppression is stopped when trying to conceive, and the plan is coordinated between your chest physician and gynaecologist.
Will it stop after the menopause?
Episodes usually stop after the menopause, because the endometrial deposits depend on oestrogen. Hormone replacement therapy should be discussed with your doctors before starting.
Can I fly with this condition?
You should not fly with an untreated or recent pneumothorax. After successful surgery and confirmation that the lung has fully re-expanded, flying is usually possible. Timing should be agreed with your doctor.
Related conditions and procedures
Consult Dr. Gogineni Ratnakara Rao
Apollo Hospitals, Financial District: Monday to Saturday, 8:30 AM to 5:00 PM. Anything in Lung Clinic, Chanda Nagar: Monday to Saturday (Thursday closed), 6:00 PM to 9:00 PM.