Chylothorax in Infants and Children

What is Chylothorax?

The accumulation of chyle in the pleural cavity. Chylothorax is a pleural collection formed by the escaping of chyle from the thoracic duct or lymphatics into the thoracic cavity.

Causes of Chylothorax

• Most common - Post-Fontan surgery
• Due to thoracic duct injury.
• Chest injury: Trauma, Child abuse
• Extracorporeal membrane oxygenation
• Malignancies: Lymphoma is the most common malignancy associated with chylothorax.
• During delivery in neonates: Due to compression of the thoracic cavity.
• Syndromes - Down Syndrome/Turner Syndrome/Noonan Syndrome
• Infections - TB and histoplasmosis
• Rarely - Lymphangiomatosis, SVC/Thoracic duct thrombosis.

Refractory chylothorax in the fetus has been associated with a missense mutation in the integrin α9β1 gene.

Clinical Features Associated with Chylothorax

Gradual onset of cough, chest discomfort, and dyspnoea but no pain. Neonates, among 50%, have respiratory distress.

Complication of Chylothorax

Related to repeated thoracentesis.

• Malnutrition: Related to fat-soluble vitamins, calorie loss, and protein loss.
• Dehydration: Because of dyselectrolytemia.
• Immunodeficiencies: Hypogammaglobulinemia, low cell-mediated immunity. Live vaccines should be avoided in neonates with chylothorax. Increase risk of infection.

Investigation

The chest X-ray and CT are the initial modalities. Thoracentesis - Gold standard

• Milky fluid with a fluid triglyceride level > 110 mg/dl.
• Pleural fluid to serum fluid triglyceride ratio is >1.0.
• Pleural fluid to serum cholesterol ratio is < 1.0.
• Chylomicrons and raised immunoglobulins.
• Cell count is 90%, and T-cell is > 1000/mm3 .

Additional Investigation

Lymphangiogram: Site of leakage can be detected.

Lymphoscintigraphy: To diagnose underlying lymphatic abnormalities

Treatment of Chylothorax

Newborns case: > 50% show spontaneous recovery

Specific therapies: Nutritional management

• Total peripheral nutrition
• Supplementation of medium-chain triglycerides, calories, proteins, and fat-soluble vitamins

Tube thoracentesis

Drugs - Somatostatin and Octreotide

Other approaches:

• Percutaneous thoracic duct immobilization
• PEEP application
• Inhaled nitric oxide

In refractory cases: Consider surgery

• Pleuroperitoneal shunt
• Thoracic duct ligation
• Pleurodesis using a sclerosing agent such as fibrin glue, talc, or iodopovidone.

Important points to remember

• Malignant chylothorax: Chemical pleurodesis or Radiotherapy is required Severe fetal / Neonatal chylothorax (Newer agent): Picibanil, Etilefrine, alpha, beta sympathomimetic agent. Lead to constriction of lymphatic vessels → reduce accumulation of chylothorax.
• Indication Neonatal surgery: Massive chylothorax and chyle output of >50 ml/kg per day despite maximum medical therapy of 3 days.
• Refractory chylothorax in the fetus has been associated with a missense mutation in the integrin α9β1 gene.
• Lymphoma is the most common malignancy associated with chylothorax.
• Most common cause of Chylothorax  - Post-Fontan surgery.
• Live vaccines should be avoided in neonates with chylothorax.
• Milky fluid with a fluid triglyceride level > 110 mg/dl.
• Pleural fluid to serum fluid triglyceride ratio is >1.0.
• Pleural fluid to serum cholesterol ratio is < 1.0.
• Gradual onset of cough, chest discomfort, and dyspnoea but no pain.

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