Catamenial pneumothorax

Catamenial pneumothorax occurs in women of child-bearing age and, by definition occurs within 72 hours before or after the onset of menstruation. Pneumothorax may be recurrent and there may be a history of pelvic endometriosis. Around 90% of pneumothoraces occur on the right.

Epidemiology

The diagnosis is not often considered and the true frequency is unknown. One study reports that 24% of 229 consecutive women of reproductive age undergoing surgery for pneumothorax were diagnosed with thoracic endometriosis on histology ⁸. 50% of catamenial pneumothoraces and 6% of non-catamenial pneumothoraces had thoracic endometriosis on histology ⁸.

Women most frequently present in their 30s and 40s. Recurrent catamenial pneumothorax has been reported in a 14 year old with no VATS evidence of thoracic endometriosis ¹⁵ .

Diagnosis

The diagnosis can be made in women of reproductive age who present with pneumothorax within 72 hours of the onset of menstruation.

Clinical presentation

Pneumothorax typically presents with chest pain, sometimes with dyspnoea. Around 90% occur on the right.

Pathology

Several mechanisms have been proposed forCatamenial pneumothorax can be caused by thoracic endometriosis including fenestrations in the tendinous portion of the diaphragm which. Diaphragmatic endometrial deposits are visiblecommonly seen at VATS. Transdiaphragmatic spread may explain the predilectionlaparoscopy for intrathoracic diaphragmatic deposits. Thepelvic endometriosis and the clockwise circulation of peritoneal fluid may explain the strong right-sided predilection. Diaphragmatic endometrial deposits are commonly seen at laparoscopy for pelvic endometriosis. Cyclical proliferation and necrosis of endometrial deposits may cause perforation ofperforate the diaphragm ¹⁴.

Other theories include passage Fenestrations in the tendinous portion of air fromthe diaphragm are visible at VATS and transdiaphragmatic spread may explain the uterus throughpredilection for intrathoracic diaphragmatic fenestrations, alveolar rupture precipitated by bronchoconstriction due to prostaglandin F2 and vascular microembolisation of endometrial tissue ¹⁴deposits.

Diaphragmatic and the less common visceral pleural deposits may fluctuate in size during the menstrual cycle. At histology, endometrial stroma with positive oestrogen and progesterone receptors and positive CD10, (see case 4) may be accompanied by haemosiderin-laden macrophages.

Elevated serum titre of the Ca125 antigen may be a helpful indicator of endometriotic disease ¹⁴.

Radiographic features

In general, no specific diagnostic imaging criteria exist. AlthoughAlthough pneumothoraces are approximately 90% right-sided, left-sided pneumothoraces and synchronous or metachronous bilateral pneumothoraces can occur ^7,10,11. Haemopneumothorax is also reported.

Plain radiograph

Imaging features are often identical to pneumothoraces from other causes although adhesions may be apparent and pneumoperitoneum may coexist.

Nodules of endometriosis may be too small to identify. Larger nodules may be seen along the diaphragm or on the visceral pleura. One case report retrospectively identified small diaphragmatic air bubbles ¹⁶.

CT

CT is a more sensitive technique to demonstrate the above findings, including small nodules and defects. Occasionally part of the liver may herniate through a larger diaphragmatic defect (collar sign) ⁷.

MRI

MayMRI may suggest pleural-based masses attributable to endometrial implants ⁷.

Treatment and prognosis

Most catamenial pneumothoraces are small and self-resolving however. VATS treatment of thoracic endometriosis includes partial diaphragmatic resection and repair, excision of all visceral pleural implants and talc pleurodesis are typically. This is followed by hormone therapy to lessen the chance of recurrence which can be as high as 40% ¹⁴. Continuous administration of the oral contraceptive pill causes atrophy of the endometrium and avoids cyclic proliferation and necrosis of endometrial deposits.

History and etymology

It was initially described in 1958 by Maurer ⁷. The term 'catamenial' was coined by Lillington in 1972 ⁹. It is derived from the Greek words pertaining to and monthly ^2,10.