What is Chylothorax (Lymphatic Fluid in the space Between the Chest Wall and the Lung)?
Chylothorax refers to the build-up of a milky body fluid known as chyle in the space around the lungs, or pleural cavity. This fluid, chyle, originates from a part of our digestive system known as the lacteals. We get chyle from our diet, specifically small and medium-sized fat molecules that our digestive system breaks down and absorbs into our bloodstream.
However, our bodies can’t easily break down and absorb large fat molecules. These larger molecules combine with other substances in our gut to form larger structures known as chylomicrons in a region of the small intestines called the jejunum. From there, these larger molecules are absorbed into our lymphatic system, which is sort of like a secondary circulation system within our bodies, forming the chyle.
The lymphatic system from the intestines combines with similar systems from other parts of our bodies, forming the thoracic duct system. This system ultimately drains back into our general circulation. But, if there’s a break or damage in this thoracic duct, the chyle can leak out into surrounding areas. When this happens, and the chyle fills the space where our lungs are located, we call that chylothorax.
Given that our bodies produce on average about 2.4 liters of chyle daily, it means a significant amount of chyle can build up in a short time if the thoracic duct is damaged. The first time chylothorax was described was in the 17th century by Dr. Bartloet. Over the past decade, there have been advances in managing this condition, leading to better outcomes for patients.
What Causes Chylothorax (Lymphatic Fluid in the space Between the Chest Wall and the Lung)?
: Chylothorax, a condition where a certain type of fluid called chyle accumulates in the chest, can be triggered by three main factors: spontaneous or non-traumatic causes, trauma, and unknown causes. Traditionally, more chylothorax cases were due to non-traumatic reasons which accounted for about two-thirds of all cases. However, in recent times, traumatic chylothorax, specifically post-surgery cases, constitute over half of all known cases reported in medical studies.
Non-traumatic chylothorax could be resulting from:
1. Inborn causes or Congenital chylothorax: It can occur standalone or in conjunction with other inherited lymphatic disorders like lymphangiectasis and lymphangiomatosis, heart diseases present from birth, tuberous sclerosis, or chromosomal abnormalities like trisomy 21, which is Down syndrome, or Turner syndrome.
2. Neoplastic chylothorax: This is the most common cause of non-traumatic chylothorax that typically arises due to cancers like lymphoma, chronic lymphoid leukemia, lung or esophageal cancer, or cancer spread from other parts of the body. Recent data shows lesser incidence of chylothorax in patients with lymphoma, probably because of early diagnosis and treatment of the cancer before chylothorax can evolve.
Infections cause chylothorax predominantly in developing nations resulting from tuberculous lymphadenitis. Some other known infections causing chylothorax include aortitis, histoplasmosis, and filariasis. Other rare but reported causes span a wide range of diseases from cattleman disease, sarcoma, sarcoidosis, to syndromes like yellow nail syndrome, Noonan syndrome, Down syndrome, and others. Most of these diseases obstruct or destroy the thoracic duct, causing chylothorax. Also, rapid infusion of nutrient solutions containing high levels of triglycerides potentially leading to chylothorax has also been noted.
Traumatic chylothorax occurs if the thoracic duct is damaged in its course in the mediastinum. This can be a complication following surgery or can occur due to blunt or penetrating chest injury.
Postoperative chylothorax is now the most common cause of chylothorax due to medical advancements. The risk of chylothorax post-surgery depends on the type of surgery. Surgeries like Esophagostomy and lung resection with or without lymph node dissection carry substantial risks. Central line placement, pacemaker implanting, and embolization of pulmonary arteriovenous malformation, surgeries in the lower neck, and mediastinum also carry the risk of chylothorax. Ingestion of milk before surgery is suggested as it causes the thoracic duct to be discolored, hence easier to visualize during surgery thereby reducing the risk of chylothorax.
Blunt trauma to the chest or spine can damage the thoracic duct causing chylothorax. Even minor incidents like coughing and sneezing, or penetrating injuries like gunshot and stab wounds can trigger chylothorax.
Around 10% of all chylothorax cases are idiopathic, meaning the cause remains unknown even after extensive investigation. These cases are mostly linked with undiagnosed cancer.
Risk Factors and Frequency for Chylothorax (Lymphatic Fluid in the space Between the Chest Wall and the Lung)
Chylothorax is an uncommon condition that can occur due to complications from chest and throat surgeries, or from blood cancers. It can affect individuals of any age or gender. After certain chest surgeries, around 0.2% to 1% of patients may develop this condition. The death and illness rates from chylothorax are around 10%.
Signs and Symptoms of Chylothorax (Lymphatic Fluid in the space Between the Chest Wall and the Lung)
Chylothorax is a condition that can exhibit different symptoms based on what caused it. A small chylothorax might go unnoticed and is usually found by chance during medical checkups, as it doesn’t cause any noticeable symptoms. However, if a person has a large chylothorax, they could experience problems associated with their lung capacity being constrained. This can gradually lead to breathlessness, a reduction in physical activity, and a sensation of pressure in the chest. It’s unlikely that fever and chest pain would be present. If the body gradually gets used to the condition, a person can gather a large amount of chylothorax with no complaints. In a case of chylothorax triggered by physical trauma, it could start displaying symptoms up to ten days after the injury occurred. In post-surgery patients, chylothorax is usually first detected as fluid buildup around the lungs or as lasting drainage from chest tubes placed during the operation.
When a doctor carries out a physical examination, they might find a reduction in the sounds made by the patient’s breathing and a dull sound when they tap the patient’s chest. Both these findings are linked to the size and location of the fluid. In 80% of chylothorax cases, it only affects one lung. Two-thirds of all cases occur on the right side because of where the thoracic duct, which carries the chyle fluid, is located in the body.
Testing for Chylothorax (Lymphatic Fluid in the space Between the Chest Wall and the Lung)
When dealing with suspected chylothorax, which is a type of fluid accumulation in the space around the lungs, several types of evaluations are used depending on what’s causing the fluid build-up and the resources available.
A chest X-ray is one common method for detecting fluid around the lungs, particularly in patients after surgery or who’ve experienced trauma. However, it cannot differentiate chylothorax from other types of fluid build-up.
Ultrasound, another common method, involves using sound waves to produce pictures of the body’s internal structures. It can show a fluid-filled area but also can’t determine if the fluid is indeed chyle, the fluid associated with chylothorax.
A chest CT scan, however, is more sensitive than a chest X-ray and ultrasound, making it a better tool for diagnosing chylothorax. It can sometimes even reveal the cause of chylothorax, such as tumors or traumatic injury.
MRI of the chest can show the cisterna chyli, a key area for evaluating chylothorax, in all cases. However, it’s rarely used in clinical practice since it’s not the best tool for examining thoracic pathology.
Lymphangiography, a technique used to visualize the lymphatic system, is rarely used in modern medicine, but it can pinpoint any leaks in the thoracic duct causing chylothorax. It involves injecting a dye into the spaces between the toes and observing its journey through the body. Another similar technique, nuclear lymphoscintigraphy, uses Tc99m labeled human diethylenetriaminepentaacetic acid instead of dye. Images of the chest are then taken using a gamma camera to detect any leaks.
Besides imaging, laboratory testing also plays an essential part in diagnosing chylothorax. Thoracentesis, a procedure to remove fluid from the space between the lungs and the chest wall, is performed, and the fluid undergoes several tests including white blood cell count, glucose, lactic dehydrogenase, total protein level, cytology, and microbiology smear and culture. If chylothorax is suspected, the color and lipid content of the fluid will also be examined. Chylothorax fluid often appears milky white due to its high fat content, but lab tests are needed to confirm the diagnosis. Pleural fluid with a triglyceride concentration greater than 110 mg/dL typically confirms chylothorax.
Sometimes, what appears to be chylothorax turns out to be pseudo-chylothorax, chyliform effusion. This type of effusion looks the same as chylothorax, but it does not contain chylomicrons or long-chain fatty acids and is associated with different conditions such as tuberculosis and chronic rheumatoid pleural effusion. This fluid’s characteristics include a cholesterol concentration typically more than 200 mg, triglycerides level less than 110 mg/dL, and a cholesterol to triglycerides ratio of over 1.
Treatment Options for Chylothorax (Lymphatic Fluid in the space Between the Chest Wall and the Lung)
Treating chylothorax, a specific type of bodily fluid accumulation, depends on its cause. This can involve a range of methods such as changes in diet, a process called pleurodesis to stick the lung to the chest wall and stop fluid build-up, or tying the thoracic duct, one of the body’s main lymphatic vessels. Recent developments include the use of certain medications to prevent fluid creation, as well as new surgical techniques. Often, patients go through a staged treatment plan, starting with less invasive methods before moving to more advanced techniques, if necessary.
Regarding dietary therapy, since the chylous fluid builds up due to long-chain fatty acids, reducing or completely removing these from a patient’s diet can lead to less fluid build-up. This can cause the leak to seal itself. Although effective, this low-fat diet can lead over time to malnutrition. Therefore, alternatives like small chain and medium-chain fatty acids in the patient’s diet and intravenous long-chain fatty acids can be provided as supplementary options.
In many initial cases, chylothorax is managed through procedures to remove the fluid, which can help alleviate difficulty in breathing caused by the excess fluid. This technique is particularly effective if the fluid retention in the chest cavity is gradual. In contrast, a surgical procedure known as a chest tube is often used in chylothorax following surgery. There can be risks of malnutrition and infection due to the fluid loss, particularly if the drainage goes on for an extended period. Therefore, it’s generally recommended to limit continuous fluid drainage to less than two weeks and to consider surgery if drainage exceeds 1.5 litres per day.
Pleurodesis, a technique to induce adhesion between the lung and chest wall to prevent fluid build-up, should be considered if fluid continues to reaccumulate despite dietary modifications and repeated fluid removal procedures. This is often done through video-assisted thoracic surgery with talc insufflation, a procedure that can cure up to 80% of chylothorax cases. Sometimes, the thoracic duct is tied to prevent further fluid formation.
Invasive procedures such as Thoracic Duct Ligation, a technique to tie off the thoracic duct and prevent fluid build-up, can be helpful if dietary modifications and pleurodesis don’t work. This surgery may lead to a swelling condition called lymphedema, but this usually resolves over several months. There’s also a technique involving the disruption or closure of the thoracic duct, which can be increasingly used in both traumatic and nontraumatic chylothorax cases.
Emerging therapies include medications such as somatostatin and octreotide that can reduce gastric, pancreatic, and bile secretions, lowering the total flow of gastric lymphatics. By reducing fluid creation and flow rates, these medications can help resolve the leak in the thoracic duct. This approach has shown promise in many chylothorax cases, including spontaneous chylothorax, congenital chylothorax, postoperative chylothorax, and chylothorax due to cancer.
In addition to these treatments, a medication known as sirolimus, used to treat a condition called lymphangiomyomatosis, has also been found to reduce the likelihood of chylothorax in patients.
Finally, procedures that shunt, or redirect, fluid from the pleural space into the venous system or abdominal cavity can also resolve chylothorax. These procedures have the advantage of recycling nutrition-rich fluid back into the body and have been successful in treating certain specific conditions and cases of postoperative chylothorax.
What else can Chylothorax (Lymphatic Fluid in the space Between the Chest Wall and the Lung) be?
- Complex health issues related to AIDS
- Heart failure leading to a buildup of fluid
- A collection of pus in the space between the lung and the inner surface of the chest wall
- Fluid build-up due to inflammation or disease in the space around the lungs
- Blood accumulated in the space between your chest wall and lungs
- Fluid build-up as a result of cancer inside the space that surrounds the lung
- Pleural effusion that develops due to pneumonia
- A rare condition where the pleural space fills with a milky white fluid similar to lymph