An Insight Into the Endometriosis of the Pleura

Introduction:

Endometriosis is a condition in which the cells that normally line the uterus tend to grow in other parts of the body. These tissues are called endometrial implants. Mostly, the patches of endometrial tissues grow in the abdomen and pelvic regions. Very rarely, they develop on or around the lungs. About 12 % of people with endometriosis have endometrial patches of tissues that develop in regions other than the reproductive organs. This kind of endometriosis is called extragenital endometriosis. Endometriosis of the pleura can result in chest pain and shortness of breath around the time of one’s period.

What Is the Link Between Pelvic and Thoracic Endometriosis?

In a majority of people with endometriosis, patches of endometrial tissues evolve in areas near the uterus, such as the ovaries, bladder, or bowels. According to a review of research conducted in 2019, about 6 to 10 % of women of reproductive age are affected by endometriosis. The thoracic cavity is the most common site for the occurrence of endometriosis of the pleura or thoracic endometriosis. The link between pelvic and thoracic endometriosis is as follows:

• Research shows that most women with thoracic endometriosis also suffer from the common form of endometriosis called pelvic endometriosis.

• It is estimated that about 50 to 84 % of women with endometriosis of the pleura also suffer from pelvic endometriosis.

• Thoracic endometriosis can occur spontaneously but is more prevalent in those with severe pelvic endometriosis.

• Researchers currently believe in the fact that thoracic endometriosis is a gradual advancement of pelvic endometriosis.

• It is also found that women who develop thoracic endometriosis are slightly older by the time they develop thoracic endometriosis.

• A review carried out in 2019 shows that women experience symptoms of thoracic endometriosis about five to seven years after developing pelvic endometriosis.

What Are the Causes of Endometriosis of the Pleura?

Various theories have been put forward regarding the cause of endometriosis of the pleura (thoracic endometriosis), but no specific reason could be proposed. One such cause is the occurrence of thoracic endometriosis due to retrograde menstruation. The backward flow of the menstrual blood through the fallopian tubes instead of the normal outward flow through the vagina is called retrograde menstruation.

Because of this, the menstrual blood stagnates in the abdomen and can mix with the patches of endometrial tissues. This can result in further accumulation of patches in the abdominal cavity extending its spread near the lungs. Not all women with retrograde menstruation develop thoracic endometriosis. Few other risk factors can make a woman susceptible to developing the condition. Common risk factors for developing endometriosis include:

• Having no offspring (children).

• Having a close family member with the condition.

• The onset of periods before 11 years of age.

• Experiencing frequent periods, short menstrual cycles, or heavy bleeding during periods.

What Are the Major Clinical Entities of Endometriosis of the Pleura?

The four major clinical entities are as follows:

• Catamenial Pneumothorax (CP): It is the most prevalent manifestation of the endometriosis of pleura. Catamenial pneumothorax is a collapsed lung that develops around the time of one’s period (menstruation). This can happen anytime between the previous day of the menstruation to 72 hours after the onset of menstruation.

It is estimated that about 70 % of women with thoracic endometriosis have catamenial pneumothorax. Mostly, the right lung is affected. Endometrial tissue can create holes in the diaphragm, which facilitates the flow of air and fluid into the space around the lung, resulting in lung collapse.

• Catamenial Hemothorax: The stagnation of blood in the pleural cavity (the space between the lung and the chest wall) is called hemothorax. The pressure thus exerted due to the accumulation of blood can cause the lung to collapse. Catamenial hemothorax can occur in about 15 % of women with thoracic endometriosis.

• Catamenial Hemoptysis: Catamenial hemoptysis is the repeated bleeding that occurs in the lungs at the time of menstruation. Hormonal changes are considered to stimulate bleeding in the endometrial tissue that is located in the lung parenchyma (the part of the lung that is involved in gaseous exchange). As a consequence of bleeding, catamenial hemoptysis can cause chronic anemia.

• Lung Nodules: Research done in 2021 states that about 6 % of women with thoracic endometriosis develop nodules in the lungs. The development of these nodules can cause cough, pain, and shortness of breath.

What Are the Signs and Symptoms of Endometriosis of the Pleura?

Chest pain, shortness of breath, and cough are the most common symptoms of thoracic endometriosis. The symptoms are influenced by the location of the endometrial growth. Common signs and symptoms include:

• Chest pain.

• Shortness of breath.

• Cough.

• Shoulder pain.

• Coughing up blood in case of catamenial hemoptysis.

How Can Endometriosis of the Pleura Diagnosed?

The diagnosis can be difficult since it is challenging to establish a link between the symptoms of thoracic endometriosis and the menstrual symptoms. The following diagnostic test can be used to diagnose the condition:

• Chest X-rays.

• Computed tomography (CT) scans.

• Magnetic resonance imaging (MRI).

• Bronchoscopy.

The results obtained from the tests taken during menstruation are compared with those taken during normal days. If the results show signs that happen to occur during menstruation, then the diagnosis is confirmed. Laparoscopy may be done to diagnose as well as to treat the condition. The gold standard method of diagnosis is video-assisted thoracic surgery (VATS). It is a minimally invasive technique in which a small incision is made between the ribs, and a scope (a tube-like structure) is used to locate and extract the endometrial tissue.

What Are the Ways to Treat Endometriosis of the Pleura?

The first line of treatment focuses on suppressing the ovarian hormones. This also suppresses the activity of the existing endometrial tissue and retards the growth of new patches of tissues. Medications can aid but not provide a permanent cure for this condition. About 60 % of women who took hormonal suppression therapy experienced a relapse within 12 months. Common medications include:

• Gonadotropin-Releasing Hormone (GnRH) Analogs: These drugs imitate the action of the hormone that is responsible for estrogen production and which is situated in the pituitary gland.

• Oral Contraceptives: Oral contraceptives are medications that prevent pregnancy and are available in pill, patch, or implant form.

• Aromatase Inhibitors: These medications are given to suppress the production of estrogen in the ovaries as well as in other tissues.

• Progestins: The synthetic form of the hormone progesterone is called progestin.

• GnRH Antagonists: These medications interfere with the response of the pituitary gland to the GnRH hormone, and this hinders the production of certain hormones.

Surgery:

A person with thoracic endometriosis can also have the same on the diaphragm. Hence the treatment should focus on both these regions. The patches of endometrial tissues situated in the lungs can be eliminated using video thoracoscopy. The diaphragmatic patches can be removed using laparoscopy. These procedures are minimally invasive and are keyhole types of surgeries. Following surgical procedures, one may be prescribed hormonal medication to retard the growth of new patches.

Those experiencing a relapse in spite of taking medications and undergoing surgery might require surgical removal of the ovaries, uterus, and fallopian tubes. Even after all these treatments, one might still require post-surgery hormone suppression therapy.

Conclusion:

Endometriosis of the pleura or thoracic endometriosis is an uncommon condition that can cause cough, pain, and shortness of breath. Symptoms can aggravate around the time of menstruation. Though there is no permanent cure, the symptoms can be managed with medications and surgery. However, there are chances of relapse despite medical intervention. The symptoms can slowly fade off with the onset of menopause. One should consult a healthcare professional if they experience cough, pain, or shortness of breath at the time of menstruation.