Thoracic Fluid Collection

Thoracic Fluid Collection
Paula J. Woodward, MD
DIFFERENTIAL DIAGNOSIS
Common
  • Bilateral Pleural Effusion
    • Hydrothorax
  • Unilateral Pleural Effusion
    • Chylothorax
  • Pericardial Effusion
Less Common
  • Effusions Associated with Lung Masses
    • Bronchopulmonary Sequestration
    • Congential Cystic Adenomatoid Malformation (CCAM)
  • Masses That Can Mimic Simple Fluid Collection
    • Unilocular CCAM
    • Congenital Diaphragmatic Hernia
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
  • First determine where the fluid is located
    • Pleural space, pericardial space or within a mass
  • Pleural effusion
    • Routine four chamber heart view
      • Curvilinear, anechoic fluid
      • Echogenic lung displaced medially
    • Coronal chest view
      • Lung displaced superiorly and medially
      • “Wing-like” lungs float in fluid
  • Pericardial effusion
    • Fluid collection surrounds fetal heart
    • If large, heart is seen beating in a “bag of water”
    • Lungs will be compressed posteriorly, not free floating
  • Large, unilocular cystic masses may simulate pleural effusion
    • Masses are rounded or ovoid
    • Have mass effect on lungs and mediastinal structures
      • Lung shifted away from fluid, not surrounded by fluid as in a pleural effusion
Helpful Clues for Common Diagnoses
  • Hydrothorax
    • Serous fluid collection
    • Effusions are bilateral and symmetric
    • Hallmark finding in hydrops fetalis (both immune and nonimmune)
    • Hydrops defined as fluid accumulation in 2 or more body cavities
      • Pleural effusion
      • Ascites
      • Skin edema
      • Pericardial fluid
    • Polyhydramnios and placentomegaly also often present if there is hydrops
    • Anomalies commonly associated with effusions/hydrops
      • Cystic hygroma (Turner syndrome) most common
      • Trisomy 21 (other markers usually seen); trisomy 18, 13 less likely
      • Cardiac defects
      • Cardiac arrhythmia
      • Infection
      • Cystic adenomatoid malformation (< 10% have hydrops)
    • Fetal masses causing high output failure (and possible hydrops)
      • Sacrococcygeal teratoma
      • Goiter
      • Vascular shunting: Vein of Galen malformation, arteriovenous fistulas, hepatic hemangioendothelioma, placental chorioangioma
    • First trimester pleural effusion
      • Can be seen as early as 7 weeks
      • Associated with increased nuchal translucency
      • Poor prognosis when present before 15 wks
      • Aneuploidy common: Turner syndrome most likely
  • Chylothorax
    • Chylous fluid collection
    • Effusion is unilateral
    • Primary congenital lymphatic defect
      • Atresia, fistula, or absence of thoracic duct
    • Thoracic duct crosses from right to left at 5th thoracic level
      • Level of obstruction determines right versus left-sided effusion
      • Equal incidence of right and left-sided effusions
    • Fluid is anechoic
      • Only after neonatal feeding will chylous fluid appear “milky”
    • Mass effect common
      • Mediastinal shift
      • Flattened diaphragm
    • May lead to hydrops when large
      • Consider performing fetal thoracentesis if evidence of fetal compromise
    • 5% associated with aneuploidy
      • Turner syndrome
      • Trisomy 21
      • Noonan syndrome
    • Amniocentesis warranted
    • 15% resolve in fetal life
    • Near 100% survival without hydrops and normal chromosomes
  • Pericardial Effusion
    • Seen best on standard four chamber view
    • Lenticular or oval collection of fluid adjacent to, or surrounding heart
    • Trace of fluid along one ventricular wall is normal
      • Can be up to 2 mm
      • Majority of fetuses (50-80%) have trace fluid if careful search done
      • Generally transient
      • If fetus not at increased risk, follow-up not necessary
    • Significant effusion if fluid surrounds atria as well as ventricles
    • Pericardial effusion seen in many conditions
      • Evaluate heart for structural abnormality, arrhythmia or mass
      • Look for other signs of hydrops
      • Look for signs of congenital infection
      • Look for anemia
Helpful Clues for Less Common Diagnoses
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Aug 10, 2016 | Posted by in OBSTETRICS | Comments Off on Thoracic Fluid Collection

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