Transudative pleural effusion

Case contributed by Chris Lim


Increased shortness of breath. Background history of atrial fibrillation, cardiac failure, and chronic kidney disease.

Patient Data

Age: 90 years
Gender: Female

Initial imaging


Imaging demonstrating large right and small left pleural effusion. No changes of interstitial or alveolar pulmonary edema present, although right-sided consolidative changes are not excluded.

Following initial imaging, a referral was made to facilitate right-sided thoracentesis and insertion of a pleural catheter for diagnostic and therapeutic purposes.

Point-of-care lung ultrasound


Point-of-care ultrasound was utilized to identify an appropriate site for thoracentesis. This is a longitudinal view of the right lower zone, with the probe marker (blue dot) oriented cranially.

This video clip demonstrates atelectatic lung floating in a large hypoechoic pleural effusion, otherwise known as 'jellyfish sign'. There is no discernable loculation, 'speckling' or 'swirling' of the fluid to suggest an exduative effusion. It is important to note that the absence of these signs is not able to exclude an exudative effusion.

The diaphragm and liver are visible on the caudal (right / inferior) side of the image, and there is movement consistent with respiration.

It is interesting to note that the right heart border is visible on ultrasound, at approximately 7cm depth. The patient was severely sarcopenic. This can also be inferred through the shallow depth of the pleural space from the surface (approximately 1.5 cm).

Pleural catheter insertion was performed on the ward without immediate complication. Handheld ultrasound was utilized to localize the site for insertion.

Drainage of pleural fluid was paused for one hour after the first 1.5L. 2,000mL of pleural fluid was drained in total, after which the patient developed coughing and right-sided pleuritic chest pain. The patient was not hypoxic or tachypneic.

The pleural drain was subsequently removed, with the onset of symptoms thought to represent catheter-related pleural irritation following adequate drainage.

Pleural fluid demonstrated a transudate, with negative cytology, negative gram stain, and nil growth on bacterial culture.

Post-removal chest X-ray (Day 1)


Inspiratory and expiratory plain films were acquired following removal of the drain. The patient did not report chest pain or dyspnea following drain removal.

Significant improvement in the right pleural effusion is seen. Interestingly, opacification of the underlying lung is seen, with air bronchogram formation suggestive of consolidation. Differential diagnosis for these appearances includes re-expansion pulmonary edema.

A small right-sided apical pneumothorax can be identified, along with evidence of pleural calcification.

Post-removal Chest X-ray (Day 6)


Improving appearances of right apical pneumothorax on day 6 post-removal. Mild increase in size of the right pleural effusion.

The patient did not require further management or intervention for their pneumothorax.

The patient's pleural effusions were transudative on sampling, and were managed with intravenous diuresis over the course of their inpatient stay. The patient was later discharged home on oral diuretics.

Case Discussion

Point-of-care ultrasound can be utilized to identify pleural effusion(s) and locate appropriate sites for drainage. Ultrasound can also be used to provide real-time guidance for pleural drain insertion.

Light's criteria is used to determine if pleural effusions are transudative or exudative.

Pneumothorax represents the most common complication of thoracentesis and develops in approximately 3% of patients when ultrasound guidance is used 1. This is significantly lower than the rate of pneumothorax in blind thoracentesis, with pneumothorax complicating up to 30% of procedures (although multiple observational studies have demonstrated rates of <12%) (2,3).

Patients who are haemodynamically unstable or develop tension pneumothorax should undergo chest tube thoracostomy or needle decompression of the pleural space.

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