Overview
Definition:
Chylothorax is the accumulation of lymphatic fluid (chyle) in the pleural space
In neonates, it is typically caused by rupture of the thoracic duct or its tributaries, leading to significant protein and lymphocyte loss.
Epidemiology:
The incidence of neonatal chylothorax is estimated to be between 1 in 3,000 to 1 in 10,000 live births
It is more common in preterm infants and those with congenital anomalies.
Clinical Significance:
Neonatal chylothorax is a serious condition that can lead to respiratory distress, malnutrition, immunosuppression, and electrolyte imbalances
Prompt diagnosis and appropriate management are crucial for survival and reducing morbidity.
Clinical Presentation
Symptoms:
Respiratory distress upon birth or within the first few days of life
Tachypnea
Grunting
Retractions
Cyanosis
Decreased feeding
Vomiting
Abdominal distension
Lethargy.
Signs:
Dullness to percussion over the affected hemithorax
Diminished breath sounds
Tracheal deviation away from the effusion
Tachypnea
Tachycardia
Hypotension
Poor peripheral perfusion
Edema.
Diagnostic Criteria:
Diagnosis is confirmed by thoracentesis revealing a milky pleural fluid with triglyceride levels > 110 mg/dL (or > 5.6 mmol/L), leukocyte count with lymphocyte predominance (typically > 1000/µL), and cell morphology consistent with chylomicrons.
Diagnostic Approach
History Taking:
Gestational age at birth
Mode of delivery
History of trauma or surgery
Presence of congenital anomalies (e.g., cardiac, pulmonary, genetic syndromes)
Duration and progression of respiratory symptoms
Feeding history.
Physical Examination:
Comprehensive respiratory examination focusing on breath sounds, percussion notes, and presence of retractions or accessory muscle use
Abdominal examination for distension or organomegaly
Assessment of hydration and perfusion status.
Investigations:
Thoracentesis for fluid analysis (triglycerides, cell count, protein, LDH, glucose)
Chest X-ray (CXR) to assess the size and location of pleural effusion
Ultrasound of the chest to confirm effusion and assess for associated findings
Echocardiography to rule out cardiac causes
CT scan of the chest with contrast may be considered for detailed anatomical assessment of thoracic duct or collateral vessels if initial management fails
Lymphangiography may be used in select cases.
Differential Diagnosis:
Other causes of neonatal pleural effusions including chyliform effusions (due to breakdown of lymphocytes), empyema, hydrops fetalis, urine ascites, protein-losing enteropathy, congenital heart disease, and congenital pulmonary airway malformations (CPAM).
Management
Initial Management:
Stabilization of respiratory status
Thoracentesis to relieve respiratory distress and obtain diagnostic fluid
Supportive care including fluid and electrolyte management
Nutritional support is paramount.
Medical Management:
Dietary modification: Initial therapy often involves replacing breast milk or formula with a medium-chain triglyceride (MCT) based formula
MCTs are absorbed directly via the portal system and bypass the lymphatic system, reducing chyle production
Total parenteral nutrition (TPN) may be used as a primary therapy or adjunct if oral intake is insufficient
Octreotide: A somatostatin analog that reduces splanchnic blood flow and gastrointestinal secretions, thereby decreasing lymphatic flow
It is administered via continuous infusion (e.g., 1-3 mcg/kg/hour) or intermittent subcutaneous injections
Its efficacy is variable and requires careful monitoring for side effects.
Surgical Management:
Surgical intervention is considered for persistent chylothorax unresponsive to medical management, typically after 7-14 days of aggressive non-operative treatment
Options include pleural-peritoneal shunting, pleurodesis (rarely in neonates), or direct surgical ligation of the thoracic duct
Thoracoscopic or open surgical approaches are employed.
Supportive Care:
Cardiorespiratory monitoring
Strict input-output monitoring
Daily weight monitoring
Close monitoring of electrolytes, albumin, and nutritional markers
Use of diuretics is generally avoided as it can exacerbate dehydration and electrolyte derangements
Prophylactic antibiotics may be considered in cases of prolonged drainage or central venous catheter use.
Complications
Early Complications:
Severe respiratory distress
Hypovolemic shock
Electrolyte imbalances (hypokalemia, hypocalcemia)
Malnutrition and failure to thrive
Sepsis
Pneumonia.
Late Complications:
Chronic pleural thickening
Recurrent effusions
Impaired immune function due to lymphocyte loss
Growth and developmental delay
In rare cases, formation of chylopericardium or chylous ascites.
Prevention Strategies:
Careful surgical technique during thoracic procedures
Prompt recognition and management of conditions predisposing to chylothorax
Optimizing nutritional support to prevent catabolism.
Prognosis
Factors Affecting Prognosis:
Underlying cause of chylothorax
Gestational age and birth weight
Severity of respiratory compromise
Timeliness and effectiveness of management
Presence of associated congenital anomalies
Development of complications.
Outcomes:
With appropriate management, the prognosis for neonatal chylothorax is generally good, with most cases resolving with conservative measures including dietary modification or octreotide
However, cases requiring surgical intervention or with severe underlying conditions have a higher morbidity and mortality
Survival rates are reported to be around 80-90% for most causes.
Follow Up:
Long-term follow-up should focus on assessing growth and development, nutritional status, and monitoring for any recurrence of pleural effusions
Pulmonary function may need to be monitored in cases of severe or prolonged effusions.
Key Points
Exam Focus:
Differentiating chylothorax from other neonatal pleural effusions based on fluid analysis
Understanding the mechanism of action and indications for MCT diet versus octreotide
Recognizing when to escalate management to surgical options
Key fluid triglyceride cut-off: > 110 mg/dL.
Clinical Pearls:
Always consider chylothorax in a neonate with respiratory distress and a milky pleural effusion
MCT-based formulas are the cornerstone of conservative medical management by bypassing lymphatic absorption
Octreotide can be a valuable adjunct or alternative when dietary management is insufficient, but its use requires careful monitoring
Surgical ligation is reserved for refractory cases.
Common Mistakes:
Mistaking chyliform effusions for true chylothorax without proper fluid analysis
Delaying nutritional support, leading to malnutrition and poor outcomes
Over-reliance on diuretics, which can worsen dehydration
Inappropriate use of antibiotics without evidence of infection.