Diagnostic Approach to Right-Sided Exudative Pleural Effusion in CKD

Initial Diagnostic Steps

The American Thoracic Society recommends performing thoracic ultrasound at initial presentation to assess safety of aspiration, effusion size, and character, looking specifically for pleural nodularity suggesting malignancy 1, 2
A detailed history should be obtained, focusing on drug exposure, occupational asbestos exposure, and symptoms suggesting infection, such as fever, weight loss, and poor dental hygiene suggesting anaerobic infection 1, 2, 3

The European Respiratory Society suggests that if ultrasound confirms safe aspiration, a diagnostic tap with a 21G needle should be performed, obtaining a 50mL sample 4, 5
Essential pleural fluid tests include protein, LDH, pH, glucose, cell count with differential, Gram stain, acid-fast bacilli stain, culture in blood culture bottles, and cytology 3, 4, 5, 6

The American College of Chest Physicians recommends that parapneumonic effusion/empyema requires immediate drainage if pH <7.2, LDH >1000 IU/L, or frank pus 3
Malignancy should be considered with pleural nodularity on ultrasound, and cytology diagnostic yield is higher when pH <7.30 and glucose <60 mg/dL 1, 2, 6

If thoracentesis is unsafe or non-diagnostic, a contrast-enhanced CT chest should be obtained, including abdomen/pelvis if malignancy is suspected 1, 2, 3
If initial workup is non-diagnostic, medical thoracoscopy may be considered for persistent exudative effusion, allowing direct visualization, targeted biopsy, and therapeutic pleurodesis if needed 1, 2