Background

Chylothorax refers to the accumulation of chyle, a milky fluid containing fat and lymphatic fluid, in the pleural space. It is typically caused by the disruption or obstruction of the thoracic duct, the main lymphatic vessel responsible for draining chyle from the digestive system. Chylothorax can result from various underlying conditions, including trauma, malignancies, infections, and congenital abnormalities. The accumulation of chyle in pleural space can lead to respiratory distress, pleural effusion, and nutritional deficiencies.

Management of chylothorax focuses on treating the underlying cause, relieving symptoms, and promoting the reabsorption of chyle. Treatment options include dietary modifications, drainage of the pleural fluid, thoracic duct ligation, and, in refractory cases, surgical interventions like pleurodesis or thoracic duct embolization. The prognosis of chylothorax depends on the underlying condition and the response to treatment. Early identification and appropriate management are crucial in minimizing complications and improving outcomes.

Epidemiology

• Incidence: Chylothorax is a relatively rare condition, accounting for approximately 1-5% of all pleural effusions.
• Age and Gender: Chylothorax can occur at any age, from newborns to the elderly. It is more commonly seen in neonates and infants, often associated with congenital heart defects or lymphatic malformations. In adults, chylothorax is more frequently observed in the 4th to 6th decades of life.
• Underlying Causes: The etiology of chylothorax can vary depending on the population studied. In neonates and infants, congenital abnormalities and surgical complications are common causes. In adults, chylothorax is often secondary to trauma, malignancies (such as lymphomas or lung cancer), or surgical procedures involving the thoracic or abdominal regions.

Anatomy

Pathophysiology

• Lymphatic System: Chylothorax occurs when chyle, a milky lymphatic fluid rich in fat, accumulates in the pleural space. It is typically a result of obstruction or disruption of thoracic duct, leading to leakage of chyle into the pleural cavity.
• Causes of Chyle Leakage: Chylothorax can be caused by various factors, including trauma or surgery that damages the thoracic duct or nearby lymphatic vessels. It can also be associated with malignancies that obstruct the lymphatic flow, such as lymphomas or metastatic cancers involving the thoracic region.
• Accumulation of Chyle: When chyle leaks into the pleural space, it leads to the accumulation of fluid, resulting in a chylothorax.
• Effects on Lung Function: The accumulation of chyle can lead to lung compression, impaired lung expansion, and decreased functional residual capacity, causing respiratory symptoms such as dyspnea.

Etiology

• Trauma and Surgery: Chylothorax can occur as a result of trauma or iatrogenic injury during surgical procedures. Trauma-related causes include chest trauma, thoracic surgery, or procedures involving the mediastinum or lymph nodes.
• Malignancies: Chylothorax can be associated with malignancies that obstruct the lymphatic flow, such as lymphomas (e.g., Hodgkin’s lymphoma, non-Hodgkin’s lymphoma) or metastatic cancers involving the thoracic region. Lymphatic obstruction may result from tumor infiltration or compression of the lymphatic vessels.
• Congenital and Developmental Abnormalities: Certain congenital or developmental abnormalities can lead to chylothorax, such as lymphangiectasia (abnormal dilation of lymphatic vessels), lymphangiomatosis (proliferation of lymphatic vessels), or congenital defects of the thoracic duct.
• Infections and Inflammatory Conditions: Infections such as tuberculosis or fungal infections, as well as inflammatory conditions like sarcoidosis or rheumatoid arthritis, can cause inflammation and scarring of the lymphatic vessels, leading to chylothorax.
• Miscellaneous Causes: Other less common causes of chylothorax include superior vena cava obstruction, thoracic duct rupture or obstruction due to thoracic aortic aneurysm or dissection, or certain medications (e.g., sirolimus).

Genetics

Prognostic Factors

PROGNOSTIC FACTORS

• Underlying Cause: The prognosis of chylothorax largely depends on the underlying cause. Chylothorax caused by reversible conditions such as trauma or iatrogenic injury generally has a better prognosis compared to chylothorax associated with malignancies or chronic diseases.
• Timing of Diagnosis and Treatment: Early diagnosis and prompt initiation of appropriate treatment can improve the prognosis of chylothorax. Delayed diagnosis or treatment may lead to complications such as malnutrition, immunodeficiency, or respiratory compromise, which can impact the overall prognosis.
• Volume of Chyle Leakage: The volume of chyle leakage plays a role in determining the prognosis. Large and persistent chyle leaks may lead to significant fluid and nutritional loss, electrolyte imbalances, and compromised respiratory function, which can affect the prognosis.
• Response to Treatment: The response to conservative or interventional treatment measures is an important prognostic factor. Chylothorax that responds well to conservative management or interventions like thoracic duct ligation or embolization generally have a better prognosis.
• Associated Complications: Complications such as pleural infection, pleural effusion recurrence, or development of other comorbidities can influence the overall prognosis of chylothorax.

Clinical History

CLINICAL HISTORY

Age Group: Chylothorax can occur at any age, but it is mostly seen in infants and young children. In adults, it is often associated with underlying conditions such as malignancies or thoracic surgeries.

Physical Examination

PHYSICAL EXAMINATION

Inspection:

• Chest asymmetry: Chylothorax may cause visible asymmetry of the chest due to fluid accumulation in the pleural space.
• Increased respiratory effort: Patients with chylothorax may exhibit increased respiratory effort, including rapid breathing or use of accessory muscles.

Palpation:

• Decreased tactile fremitus: Chylothorax can lead to decreased transmission of vibrations through the chest, resulting in reduced tactile fremitus.

Percussion:

• Dullness to percussion: Chylothorax may produce dullness on percussion over the affected area due to the accumulation of fluid in the pleural space.

Auscultation:

• Decreased or absent breath sounds: Chylothorax can cause absent or decreased breath sounds in the affected area due to the presence of fluid.

Age group

Associated comorbidity

Associated Comorbidities or Activity:

Chylothorax can be associated with various underlying conditions or factors, including:

• Congenital Disorders: Chylothorax can be seen in infants with congenital lymphatic abnormalities such as lymphangiectasia or lymphatic malformations.
• Trauma: Chylothorax can occur as a result of trauma, such as thoracic injuries or surgical trauma during procedures involving the thoracic duct.
• Malignancies: Chylothorax can be associated with malignancies involving the thoracic region, such as lymphoma, lung cancer, or metastatic tumors.
• Infections: In rare cases, infectious causes like tuberculosis or parasitic infections can lead to chylothorax.
  Thoracic Surgeries: Chylothorax can occur as a complication of thoracic surgeries, particularly those involving the lymphatic system.

Associated activity

Acuity of presentation

Acuity of Presentation:

The presentation of chylothorax can vary depending on the cause and the volume of chyle leakage. Some common features may include:

• Chest pain or discomfort
• Difficulty breathing or shortness of breath
• Coughing or wheezing
• weight loss or failure to thrive in infants
• Swelling or Edema in the limbs or abdomen (if associated with lymphatic abnormalities)

Differential Diagnoses

DIFFERENTIAL DIAGNOSIS

Pleural Effusion:

• Other types of pleural effusion, such as transudative or exudative effusions, should be considered and differentiated from chylothorax.

Malignancy:

• Lung cancer, lymphoma, and other malignancies can present with malignant pleural effusion, which may mimic the clinical features of chylothorax.

Trauma:

• Thoracic trauma or iatrogenic injury to the thoracic duct or major blood vessels can lead to chylothorax.

Infection:

• Infectious causes such as tuberculosis, fungal infections, or bacterial infections can result in pleural effusion, which needs to be distinguished from chylothorax.

Congenital Disorders:

• Conditions like congenital lymphatic malformations or lymphangiomatosis can cause chylothorax, particularly in pediatric patients.

Superior Vena Cava Syndrome:

• Superior vena cava obstruction can lead to pleural effusion, which may require differentiation from chylothorax.

Heart Failure:

• Congestive heart failure can cause pleural effusion.

Pulmonary Embolism:

• Pulmonary embolism can result in pleural effusion, which may need to be distinguished from chylothorax.

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

TREATMENT PARADIGM

Modification of Environment:

• Nil per oral (NPO): Patients may be placed on a period of fasting or restricted oral intake to reduce chyle production.
• Medium-chain triglyceride (MCT) diet: MCTs are absorbed directly into the portal circulation and can reduce chyle flow. This dietary modification involves the consumption of MCT-rich foods.

Administration of Pharmaceutical Agents:

• Somatostatin analogs: Drugs such as octreotide or lanreotide can reduce chyle production by inhibiting gastrointestinal hormone secretion.
• Parenteral nutrition: In severe cases, total parenteral nutrition (TPN) may be necessary to provide adequate nutrition while minimizing chyle production.

Intervention with Procedures:

• Thoracic duct ligation: Surgical ligation of the thoracic duct can be performed to stop the flow of chyle into the pleural space.
• Thoracic duct embolization: Minimally invasive procedures, such as embolization, can be used to occlude or block the thoracic duct and redirect lymphatic flow.

Phases of Management:

• Acute phase: In the acute setting, initial management focuses on symptom relief, drainage of pleural effusion, and conservative measures to reduce chyle production.
• Chronic phase: Once the acute symptoms subside, long-term management aims to control chyle leakage, maintain nutrition, and prevent recurrence.

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

Medication

Future Trends

Media Gallary

References

cyclothorax.ncbi.nlm.nih.gov

Chylothorax: aetiology, diagnosis and therapeutic options.ncbi.nlm.nih.gov