What Is Chylothorax?
Chylothorax is a rare condition where the lymphatic fluid (chyle) leaks into the space between the lungs and chest wall. When this fluid accumulates in the lungs, severe cough, difficulty breathing, and chest pain occur.
Chylothorax is a lymphatic flow disorder. This disorder comprises a group of diseases showing abnormal lymph fluid circulation. Chyle is fluid that contains white blood cells and proteins carried by the lymph vessels to the veins and drained into the bloodstream. Lymphatic fluids play a vital role in immune function, fat, and protein transport.
Injury to the thoracic duct (the main lymph vessel), congenital abnormalities, or increased venous pressure results in lymphatic flow problems, and fluid leakage occurs in the chest, abdomen, or other body cavities.
What Is the Predominant Use of Chyle?
Chyle is a fluid that contains a mixture of lymphatic fluid and chylomicrons that give a milky appearance. Chylomicrons are small fat globules composed of proteins and lipids combined in the intestinal lining. Chyle is vital for immune function because it transports immunoglobulin and T-lymphocytes throughout the body. It is usually found in blood and lymphatic fluid. It also helps transport fat from the intestine to the liver and adipose tissue.
What Are the Causes of Chylothorax?
Various causative agents cause chylothorax. The cause of chylothorax is classified as traumatic and non-traumatic. The traumatic cause is subclassified as iatrogenic and non-iatrogenic causes.
Injury to the central lymphatic system caused due to trauma or surgery comes under traumatic chylothorax. Other iatrogenic traumatic causes include thoracic duct damage after subclavian vein catheterization and central venous catheterization done after venous thrombosis.
Non-iatrogenic traumatic causes include thoracic duct injury following childbirth, fracture and displacement of the spine, and penetrating trauma from knife or gunshot injuries.
1) Malignancy.
2) Retrosternal goiter.
3) Sarcoidosis.
4) Amyloidosis.
5) Superior vena cava thrombosis.
6) Inherent duct anomalies.
7) Diseases affecting the lymph vessels come under non-traumatic causes of chylothorax.
Lymphangioleiomyomatosis often occurs in females of childbearing age. In this condition, there is an abnormal growth of smooth muscle cells in the lungs, lymph nodes, and thoracic duct. The clinical manifestation of lymphangioleiomyomatosis is chylothorax.
Mediastinal lymphadenopathy can also cause chylothorax. It occurs by pressing the lymphatic vessels and blocking lymph drainage from the lung periphery. Thus, extravasation of chyle occurs within the pleural space.
Systemic diseases such as tuberculosis and congenital syndromes such as Gorham-Stout, Noonan’s syndrome, and Turner syndrome might also cause chylothorax. Elevated venous pressure occurring in heart failure and pulmonary hypertension can also cause chylothorax.
Beyond these causative agents, chylothorax is mainly caused due to leakage of lymph from the thoracic duct into the pleural space. The thoracic duct is the largest lymphatic duct transporting lymph from the body to the veins. The lymph fluid might leak back when this flow is insufficient, causing chylous pleural effusion.
The other possible cause of chylothorax is chylous ascites, where leakage of intestinal lymph occurs in the peritoneal cavity. In chylous ascites, chyle from the abdomen travels into the chest cavity through the natural opening in the diaphragm.
What Are the Symptoms of Chylothorax?
Chylothorax does not show symptoms when only a small amount of fluid accumulates in the lungs. As the chyle gets collected in the chest cavity, chylothorax causes shortness of breath, cough, chest discomfort, and difficulty in breathing.
What Problems Occur if a Fetus Develops Chylothorax?
Chylothorax can occur in a fetus before birth. Chylothorax affects the baby's lung development, and blood circulation gets blocked, causing heart failure. Fluids may build in other parts of the body too. Babies affected with chylothorax also have trouble breathing, decreased resistance to infections, and difficulty gaining weight.
How to Diagnose Chylothorax?
The doctor uses a combination of imaging tests to diagnose chylothorax. The tests usually done are X-ray, CT (computed tomography), and MRI (magnetic resonance imaging). Chylothorax diagnosis is made when these imaging tests demonstrate the presence of fluid in the pleural spaces.
The doctor may test the fluid accumulated in the lungs. The fluid is also drained to see whether the problem originated from the lymphatic system. Lymphatic imaging modalities such as intranodal lymphangiography and dynamic contrast magnetic resonance lymphangiography are also done to determine the source of the lymphatic leak.
How Is Chylothorax Diagnosed in Babies and Children?
The doctor suspects chylothorax in a fetus if the routine prenatal ultrasound shows fluid around the baby's lungs. The doctor may also do further testing to confirm the diagnosis. If an infant or child has fluid around the lungs, the doctor tests the fluid to know whether it is chyle. The doctor also does an imaging test called an MRI lymphangiogram to see the leakage.
How to Treat Chylothorax?
The treatment for chylothorax depends on the cause. These patients are managed by specialized experts where the best treatment approach is provided based on the patient’s health condition.
Chylothorax is managed using two lymphatic interventional procedures when lymphatic leaks are found. Some ducts are embolized in selective lymphatic duct embolization, sparing the thoracic duct. In thoracic duct embolization, the entire thoracic duct is embolized. If chylous ascites cause chylous fluid to accumulate, embolization is not done, and the chylous ascites are treated in this condition.
How to Treat Chylothorax in Children?
When imaging tests show the presence of chylothorax in a fetus, the doctors observe the mother's pregnancy. When she delivers the baby, the baby is taken care of in the NICU (neonatal intensive care unit). In most cases, the doctor removes the fluid around the children's lungs to make them breathe comfortably.
In some cases, chylothorax is caused by a leak in the lymphatic system. It is healed by taking medicines and a low-fat diet in children, which helps the body make low chyle and heals the leak soon. Some kids may get total parenteral nutrition. Delivering nutrition through a vein makes the body produce less chyle. Surgery is done when the child's nutritional status lowers despite following conservative management.
Conclusion:
Chylothorax is a rare disorder causing leakage of lymphatic fluid in the space between the lungs and chest. It presents as a unique medical condition, causing variant features in developing fetuses, children, and adults. If a person or child faces any of these symptoms mentioned above, they can consult a specialist online to know more about chylothorax and their management options.
