Respiratory Distress is a common emergent complaint encountered when caring for children. Whether it is Out of Control Asthma or Pneumonia, or Severe Croup or Aspirated Foreign Bodies, or Bronchiolitis or Heart Failure, or Spontaneous Pneumothorax or Traumatic Pneumothorax … (goodness, that is a lot of stuff!) we have to be prepared to evaluate and manage a wide variety of conditions that may initially look very similar to one another. Of course, sometimes even when we make the correct diagnosis and management plan, things can become even more complicated (ex, Negative Pressure Pulmonary Edema, Mechanical Ventilation for Status Asthmaticus). Let’s take a look at a condition that may catch you by surprise and, even once managed appropriately, deserves specific vigilance- Pediatric Pleural Effusion and Reexpansion Pulmonary Edema: (it’s like 2 Morsels for the price of one!)

Pleural Effusion: Basics

• Pleural effusion = fluid accumulation in pleural space.
• Occur at ANY AGE … even neonates! [Lee, 2018]
• Occur when rate of absorption < rate of accumulation
• Factors that influence development of pleural effusion: [Lee, 2018]
  • Hydrostatic Pressure
  • Oncotic Pressure
  • Lymphatic Pressure
  • Regional Inflammation

• Clinical presentation of pleural effusions depends on size of effusion and any associated medical conditions/causes.

Pleural Effusion: Causes

• There are numerous causes!
  • Anything that affects the factors noted above can lead to pleural effusion.
  • Often individual causes influence development via multiple factors.
  • Infection is the leading identified cause of pleural effusions. [Utine, 2009]
    • Parapneumonic Effusion accounted for ~78% of cases in one study. [Utine, 2009]
    • Tuberculous is a notable cause as well. [Utine, 2009]
  • Malignant Effusions accounted for ~4% of cases. [Baniak, 2017; Utine, 2009]
  • Congenital Heart Diseases accounted for ~1% [Utine, 2009]
  • Chylothorax accounted for <1% of cases. [Utine, 2009]
  • Many causes go Unidentified. [Utine, 2009]

• Acquired or Iatrogenic pleural effusions occur TWICE as often as congenital effusions. [Lee, 2018]

Pleural Effusion: Management

• Imaging:
  • CXR is often first image obtained and may show:
    • Fluid in fissures
    • Blunting of costophrenic angle
    • Mass effect
    • Meniscus formation
  • Ultrasound should be considered early!
    • It is timely and “easy” to do at the bedside …
      • So sick child doesn’t have to leave your department
      • Check out video at bottom of this page (and on mededmasters.com)
    • Can detect smaller volumes of effusion than CXR.
  • CT may be useful in evaluation, but not until patient is clinically stable.
    • May help show associated anatomic abnormality or cause (ex, migrated VP shunt tip). [Porcaro, 2018]
    • May show associated traumatic injuries (if effusion related to trauma). [Kulaylat, 2014]

• Drainage / Thoracentesis:
  • Small bore catheters are generally favored over large calibre tubes.
    • Better tolerated.
    • Less complication risk.
    • Do the job!
    • See Morsel on Pigtails Catheters.
  • SMALL Asymptomatic pleural effusions may resolve with treatment aimed at underlying condition.
    • Medical Management may include:
      • Specialty nutrition with high medium-chain triglyceride content (decreases intestinal lymph production and decreases flow through thoracic duct).
      • Octreotide may reduce need for surgical intervention.
    • Treat underlying issue:
      • If related to uremia – initiation of hemodialysis. [McGraw, 2017]
      • If central line in place, remove as it may be causing obstruction. [Lee, 2018; Siddiqui, 2015]

• Characterize Pleural Fluid:
  • Samples of pleural fluid should be sent for: [Lee, 2018]
    • pH
    • Cell Count
    • Gram Stain and Culture
    • Protein
    • Glucose
    • Lactate Dehydrogenase
    • Triglycerides
  • Transudative vs. Exudative Process [Lee, 2018]
    • Exudative effusion tend to have:
      • Cloudy appearance
      • Specific gravity > 1.020
      • Elevated protein
      • Lactate dehydrogenase levels > 2/3rds the serum level
    • Transudative effusion tend to have:
      • Clear appearance
      • Specific gravity < 1.012
      • Protein level < 2.5 g/dL
      • Fluid Protein: Serum Protein < 0.5
      • Lactate dehydrogenase level < 2/3rds the serum level
    • Light’s Criteria is often used to help classify pleural fluid, although it hasn’t been validated in children. [McGraw, 2018; Less, 2018]

ReExpansion Pulmonary Edema

• Reexpansion Pulmonary Edema is uncommon, but can occur AFTER expansion of a collapsed lung.
• Most commonly described in the setting of treatment of Pneumothorax or Pleural Effusion. [Hirsch, 2018]
• Risk Factors: [Hirsch, 2018]
  • There is no clear evidence to attribute any specific risk factor for development of Reexpansion Pulmonary Edema in children.
  • Some considerations though are:
    • Younger age
    • Use of high suction pressure (recommended to use between -10 to -20 cmH2O, or even just water seal at first).
    • Chronically collapsed lung
    • Larger size of Pneumothorax or Pleural Effusion
  • In the end, Reexpansion Pulmonary Edema can occur in a variety of situations and requires vigilance.
• Presentation: [Hirsch, 2018]
  • May be asymptomatic (only seen on repeat imaging)
  • Tachypnea, worsening dyspnea
  • Cough, sometimes productive with pink frothy sputum

Moral of the Morsel

• Be Kind! Use a pigtail catheter to drain effusion.
• Characterize the Fluid! Light’s Criteria may help distinguish exudative from transudative, but nothing is perfect.
• Don’t ignore that cough! After placement of the pigtail catheter, don’t just assume all will be fine. Monitor for Reexpansion Pulmonary Edema.

References