Case History

A 40 year old woman presented with her fifth right sided spontaneous pneumothorax. She specifically recalled that the last two had coincided with menstruation.  Localised, stable pelvic endometriosis had been diagnosed at laparoscopy 5 years previously during investigation of  infertility. She had subsequently had a successful pregnancy following in-vitro fertilisation. She wished to have further children and declined hormonal treatment for her pneumothoraces. She was offerred surgery to prevent recurrence.

The initial exploration was via thoracoscopy but it was felt that the extensive diaphragmatic fenestrations required patch repair, so the approach was changed to muscle sparing thoracotomy.

Inspection of  the right diaphragm revealed multiple fenestrations with thinning of the diaphragm over an area 6cm in diameter. No endometrial deposits were seen on the visceral or parietal pleura. There were no bullae or blebs.

After completing a pleurectomy, the diaphragmatic defect was covered with a Vicryl mesh (Ethicon Products UK, Edinburgh)  to encourage adhesions and seal the diaphragm.

The patient made an uncomplicated recovery and has had no subsequent pneumothoraces.

Catamenial Pneumothorax

Catamenial pneumothoraces (CM PMX) are thought to be a rare cause of spontaneous pneumothoraces in females. However, detailed questioning will often reveal a history of pneumothoraces or pleuritic chest pain  at the time of menstruation. The incidence may be more common than we realise.

The pneumothoraces are often small and may be missed if inspiratory and expiratory chest films are not taken. The pneumothoraces can present with little more than a wheezing-type syndrome, often mistakenly diagnosed as asthma.

Female patients have a higher recurrence after pleurectomy or pleurodesis. This may be due to lack of understanding of the condition and failure to address the diaphragm.

The psychological consequences can be significant with some patients being labelled as hypochondriac. In others the symptoms are not believed because they occur ever month at the same time, A&E doctors often being ignorant of the condition. In one extreme case in my practice, a trainee nurse was diagnosed by the great and good of psychiatry as having Munchausen’s syndrome. This was around the time of the celebrated Beverly Allett case of “Munchausen’s syndrome by proxy”, and the girl’s politically correct if medically ignorant nursing supervisors had suspended her from training in her chosen career. An extensive pleurectomy with specific attention to the diaphragm ended the attacks of pain and wheezing. A tactfully worded letter to the nursing hierarchy restored the girl’s career, her sanity and a good nurse to her profession

Causes of catamenial pneumothorax

  1. Breakthrough bleeding - the commonest cause of menstrual bleeding is failure to continue oral contraceptive (OCP) medication while in hospital with a pneumothorax of other cause. Some women may fail to tell hospital staff of the OCP as they don’t regard it as true medication. The intern may forget to ask! In one’s enthusiasm to diagnose CM PMX one not ignore this possibility.

  2. Typical blebs - statistically 20-25% of pneumothoraces occurring in menstruating women will occur at the time of menstruation. Therefore a pneumothorax may coincide with menstruation but not be true catamenial. It is true that thrombogenesis and fibrinogenesis are altered at this time, and some authors have suggested that this altered milieu may allow the persistence of a pneumothorax which may at other times have healed spontaneously without coming to medical attention.

  3. Endometriosis - the classic theory of CM PMX is that of endometrial deposits on the lung. These have been described on the lung surface but in 25 years of Thoracic surgical practice I have yet to excise one histologically confirmed deposit of endometriosis from the lung surface. The theory is that as the deposits break down with each menstrual cycle, air is released into the pleural space and a pneumothorax ensues. How these deposits reach the lung and why there is not just a haemothorax rather than a pneumothorax is not entirely clear. I would postulate that the endometrial deposits reach the pleura via diaphragmatic fenestrations, and that it is the fenestrations which allow the pneumothoraces rather than the endometrial deposits.

  4. Diaphragmatic fenestrations - fenestrations are well described from the complete diaphragmatic agenesis, through lesser defects like the Bochdalek hernia to the more relevant micro-fenestrations as seen in the above case. The fenestrations are usually not as numerous as in this case but allow passage of air in any case. These fenestrations are the probable mechanism of Meig’s syndrome (right sided pleural effusion with benign ovarian fibroma). They are also the means by which ascitic fluid causes a pleural effusion in liver failure or abdominal malignancy. They are more commonly seen on the right, as are CM PMX, probably because omentum plugs the holes on the left, whereas those on the right are maintained open by the presence of the liver. In women, the fallopian tubes open into the peritoneum. At menstruation, the cervix opens and air can thus enter the peritoneum. When in an erect posture, the air rises to the diaphragm, maybe contributing to menstrual pain. If there are fenestrations, it reaches the pleural space causing a pneumothorax.

  5. Other - pneumothoraces can occur in relatively young smokers as a consequence of emphysema. As with typical blebs, these pneumothoraces can coincide with menstruation but not as a result of it.


  1. Hormonal

  2. Abrasion

  3. Oversewing

  4. Absorbable mesh

  5. Talc

Catamenial pneumothoraces can be treated by hormonal control of the menstrual cycle. The OCP can be used for this purpose. However, in the older patient, or where pregnancy is desired, hormonal manipulation is not appropriate

When surgically treating women with pneumothorax, the surgeon must not only look for bullae in the routine sites (apex, apex of lower lobe, fissures, diaphragmatic surface), but also examine the diaphragm. This may require placing the thoracoscope through one of the higher operative ports to get a good view of all the diaphragm. The pores usually occur on the tendinous dome of the diaphragm.

If fenestrations are seen they can be dealt with in a number of ways. Simple abrasion is unlikely to be successfully as the diaphragm is hard to abrade, having the consistency of a blanc mange (jello for you Americans). If fenestrations are limited in number, simple oversewing will suffice. However, if numerous and diffuse as in the above case, covering the diaphragm with an absorbable mesh will ensure dense adhesion formation with effective closure of the foramina. The procedure is completed by apical pleurectomy and abrasion of the remaining basal pleura.

Talc applied to the diaphragmatic surface will ensure effective pleurodesis. I generally do not like to use talc in young patients, but will use it in association with complete pleurectomy in cases of recurrences after other forms of pleurodesis.


As I mentioned above recurrence is more common if the surgeon fails to recognise the catamenial pattern and treat the cause of the CM PMX.