Catamenial pneumothorax: period-related collapsed lung and thoracic endometriosis

A pneumothorax happens when air leaks from a lung into the gap between the lung and the ribcage (the pleural space). Asthma + Lung UK explains that air building up in this space can squash the lung and cause it to collapse, which is why it is sometimes called a collapsed lung. A pneumothorax may cause few symptoms and heal by itself, but sometimes needs treatment.

Catamenial is derived from the Greek word for monthly occurrence. Catamenial pneumothorax is defined in the Journal of Thoracic Disease review as spontaneous recurrent pneumothorax in women of reproductive age, in a temporal relationship with menstruation. The charity says it is a rare type of primary spontaneous pneumothorax and that if a pneumothorax occurs three days before or after the start of a period it could be catamenial.

The cause is not fully settled. Asthma + Lung UK says the reasons are unknown but early research has linked it to endometriosis, the condition in which tissue similar to the womb lining grows elsewhere in the body. Endometriosis UK describes thoracic (chest) endometriosis as rare and lists shortness of breath and chest pain specifically during a period among its symptoms.

The Journal of Thoracic Disease review describes several theories. One suggests that endometrial tissue spreads to the lungs or diaphragm and breaks down with each period, causing air leaks. Another suggests that air passes from the vagina through the uterus and tubes into the abdomen and then through small holes in the diaphragm into the chest. A third suggests that hormonal changes during menstruation make existing blebs or bullae more likely to rupture. No single theory explains every case.

Symptoms are those of any pneumothorax, with the distinguishing feature being the timing. Asthma + Lung UK lists a sudden sharp stabbing pain in the chest or shoulder, chest pain that gets worse when you breathe in, breathlessness, a cough and clicking, bubbling or crunching in the chest.

Because it is rare, the link with the menstrual cycle can be missed. If you have had a collapsed lung more than once, particularly around your period, mention this to your doctor and keep a note of the dates alongside your menstrual cycle.

A pneumothorax is confirmed on imaging; Asthma + Lung UK lists a chest X-ray, CT scan, ultrasound and blood tests. The review notes that diagnosis of catamenial pneumothorax can be hinted at by high recurrence rates of lung collapse in a woman of reproductive age with endometriosis, and that video-assisted thoracoscopy or medical thoracoscopy is used for confirmation, since it allows direct inspection of the diaphragm and pleura and biopsies.

The review reports that it most commonly occurs in women aged 30 to 40 and that most have a history of pelvic endometriosis, although it has been diagnosed in young girls as early as 10 years of age and in postmenopausal women. Gynaecological assessment is therefore often part of the work-up.

The immediate treatment is the same as for other pneumothoraces. Asthma + Lung UK says some heal on their own, and when treatment is needed options are a chest drain, needle aspiration or a small one-way valve (vent). If a pneumothorax happens more than once on the same side, a small operation to prevent recurrence may be offered.

For catamenial pneumothorax the review states that video-assisted thoracoscopic surgery is considered the treatment of choice, with procedures including pleurodesis (making the lung stick to the chest wall), diaphragmatic repair and lung resection. It also states that hormonal treatment as an adjunct to surgery prevents recurrences, suggesting a gonadotrophin-releasing hormone analogue for 6 to 12 months after surgery, and multidisciplinary management. The review is from 2014 and international guidelines for this rare condition are limited, so ask your team about current local practice.

Asthma + Lung UK says that after a spontaneous pneumothorax there is a risk of recurrence, and that you should not scuba dive after having a pneumothorax as there is a high risk that it will happen again. It advises not flying until the pneumothorax has completely gone, which is usually a week after it heals, and telling your travel insurer. Stopping smoking reduces the risk of recurrence.

There is help if you feel anxious or stressed after a pneumothorax, which the charity says are normal feelings. Endometriosis UK offers information and support for people with endometriosis.

Asthma + Lung UK says to call 999 if you get sudden pain or discomfort, pain that spreads to the left or right arm, neck, jaw, stomach or back, or chest pain with feeling sweaty, sick, light-headed or breathless. A tension pneumothorax, where pressure builds in the chest, is described as a medical emergency. See a GP for chest pain that comes and goes or goes away quickly but still worries you.