Introduction

Catamenial Pneumothorax is a rare condition in which the air accumulates around the lungs a few days before the onset of menstruation or Period. It may occur every month, synced with the cycle. The exact cause of this condition is not known. It is observed in women suffering from hormonal problems or endometrial diseases, where tissues normally found in the lining of the uterus grow outside the uterus, such as in the chest cavity. There are multiple hormone suppression therapies available that play an important role in treating Catamenial Pneumothorax and decreasing the chances of recurrence.¹

Catamenial pneumothorax

Catamenial Pneumothorax is a mysterious yet fascinating condition found in women, characterised by the accumulation of air around the lungs. Catamenial is a scientific term which means “related to period”, and Pneumothorax means “air in the chest Cavity”. The accumulated air in the pleural cavity flows around the chest area and causes lung collapse and pain in the right lung.²

Cause of catamenial pneumothorax

The exact cause of this condition is not known; however, it can be associated with endometriosis. Endometriosis is a condition where cells similar to the lining of the uterus grow in other parts of the body as well.

If you have endometriosis in the diaphragm, then it is likely the cause of catamenial hemothorax. Each month, just before the onset of the menstrual cycle, the uterine lining thickens and sheds, thus marking the beginning of the monthly cycle. Similarly, when the uterine line near the lungs or diaphragm sheds, it creates holes or fenestrations in the diaphragm.³ These holes provide a pathway for the air to travel from the abdomen and into the chest, where it accumulates and causes the lungs to collapse 72 hours before the onset of menstruation.⁴

Role of hormones

Progesterone and Estrogen are the two hormones that play a role in regulating the menstrual cycle. Their levels are always fluctuating, and right before the start of the cycle, their levels drop, which causes the endometrium lining in the uterus and the chest cavity to shed.⁵ The shedding of the uterine lining marks the onset of the normal menstrual cycle. However, the anomaly shedding of the uterus into the chest cavity is harmful, causing inflammation and holes in the diaphragm and allowing air to accumulate around the lungs. 

Signs and symptoms

• Chest pain
• Shortness of breath
• Increased Heart rate
• Rapid Breathing
• Fatigue
• Pleural Effusion

Goals of hormonal suppression therapy

The goal of the hormonal suppression therapy is to either reduce or stop the activity of the endometrial tissue lining. These therapy goals are to prevent the lung from collapsing and chest pain.

It aims to reduce or stop menstruation as it seems to be the trigger for catamenial pleurothorax. This approach to completely stop the menstrual cycle is not preferred with mothers expecting to conceive, as this can lead to other problems, such as miscarriages.

The overall goal is to improve the quality of life for the patient and reduce the chances of surgery in early cases.

Hormonal treatment options

GnRH agonists

Gonadotropin-releasing hormones stop the production of reproductive hormones (Progesterone and Estrogen) by acting on the Gonadotropin receptors present on the pituitary gland. They work by initially increasing the secretion of Luteinizing hormone(LH) and the follicle-stimulating hormone(FSH), which releases more progesterone and estrogen. Due to continued stimulation of the GnRH receptors, they become desensitised and stop responding, which ultimately stops progesterone and estrogen production and stops the menstrual cycle.

Progesterone and Estrogen fluctuating levels in endometriosis are responsible for the inflammation and pain in the lungs and diaphragm, thus inhibiting these hormones with GnRH agonists helps in managing Catamenial Pneumothorax.⁶ They can induce a temporary menopause in young women since the reproductive hormones are not produced, and the menstrual cycle cannot start.

Some of the GnRH agonists are:

• Leuprolide
• Goserelin
• Nafarelin

Side effects

• Some women feel hot flashes
• Mood swings
• Bone density loss
• Vaginal Dryness
• Sleep Disturbances

Danazol

Danazol is a synthetic steroid which is used in endometriosis, uterine fibroids and heavy menstrual bleeding. They work by inhibiting the pituitary gland, which inhibits the steroidogenesis of progesterone and estrogen in the ovaries. Since there is no more stimulation for the production of these hormones, the uterine lining present in the chest also stops producing the reproductive hormones, and therefore, there is no more shedding, pain or inflammation.⁸

Dose:

For mild Endometriosis: 200-300mg 2 times daily for 3-9 months

Moderate to severe: 400mg 2 times daily for 3-9 months⁸

Side effects

• Weight gain 
• Bloating 
• Vomiting
• Gastroenteritis
• Depression
• decreased breast size
• Acne
• Hair loss
• Oily skin and skin
• Menstrual irregularities

Progestins

Progestins are the synthetic form of the naturally produced progesterone. They mimic the action of progesterone and help in managing endometriosis-related pain symptoms.⁹

Progestins manage catamenial Pneumothorax by endometrial suppression; they inhibit the growth of the endometrial tissue in the lungs, diaphragm and ovary, making it thin and less active, so that it does not shed and bleed anymore. Some progestins can exhibit anti-inflammatory effects and provide instant relief.

Some progestins available are

• Medroxyprogesterone acetate
• Dienogest
• Norethindrone acetate

Side effects

• Breast tenderness
• Nausea
• Bloating
• unscheduled bleeding
• Thromboembolism
• Mild Increase in blood pressure

Combined oral contraceptives (COCs)

Combined oral Contraceptives are the two synthetic hormones Estrogen (ethinyl estradiol) and Progestin (drospirenone, norethindrone). They play a very important part as birth control, but they are also used to treat endometriosis, Catamenial pneumotheorax and other conditions.

These synthetic hormones suppress the ovulation process by inhibiting the LH and FSH from the pituitary glands, which leads to low and stable levels of progesterone and estrogen. The constant fluctuations in these hormones trigger the endometrial lining to shed and bleed; therefore, once their levels are stabilised(low), the stimulation of the endometrial lining stops and therefore the endometrial lining in the thoracic cavity also stops bleeding.

Moreover, Progestin thins the endometrial lining, which makes the endometrium even more inactive and stable.

Side effects

• Nausea
• Bloating
• Mood swings

COCs tend to be more effective in women suffering from mild endometriosis as they only partially suppress hormones. They might not be helpful in more severe cases as GnRH agonists or Danazol. They are a good option for young women who may want to conceive a child in the future.

Video-assisted thoracoscopic surgery (VATS)

When hormonal therapy isn't effective in treating catamenial pneumotheorax and you keep experiencing the symptoms every month, then it is best advised to consider surgery.

VAT surgery (Video-Assisted Thoracoscopic Surgery) removes the endometrial deposits in places such as the lungs and diaphragm. It is a minimally invasive procedure that cuts the uterine line deposits present in the chest cavity. This surgery also helps in restoring the holes in the diaphragm and blocks the pathway to stop air accumulation in the airway. VAT surgery provides long-term relief from endometriosis-related Catamenial Pneumothorax. Once the surgery is successful, the patients are directed to take GnRH agonists or oral contraceptives to minimise the regrowth of the endometrial lining in the chest area.

Summary

Catamenial Pneumothorax is a rare condition in which air is present in the lungs, days before the onset of menstruation or Period. It may occur every month, synced with the cycle. The most likely cause of Catamenial Pneumothorax is Endometriosis. The fluctuations in the progesterone and estrogen levels cause the uterine lining to shed and bleed, which causes pain and accumulation of air in the lungs. There are multiple therapies available for treating endometriosis, such as GnRH agonists, Danazol, COCs, and Progestins. These medications manage the endometriosis-related catamenial pneumo- and pleural effusions and provide relief. If these medications are not effective, the VAT surgery is opted for as the last option, which is a non-invasive procedure and provides lasting relief.