36. Top Consults Series: Approach to Pleural Effusions

Pleural effusion management requires a systematic approach to differentiate between transudative and exudative etiologies, primarily through Light’s criteria and serum-pleural fluid gradients. While transudates often stem from systemic conditions like heart failure, exudates necessitate further investigation into inflammatory or malignant causes. Bedside ultrasound is essential for identifying safe sampling pockets and mitigating procedural risks, including pneumothorax and re-expansion pulmonary edema. Diagnostic thoracentesis provides critical data through cell counts, LDH levels, pH, and glucose analysis, which help distinguish between simple parapneumonic effusions, complicated cases, and empyema. For instance, an LDH exceeding 1,000 or a pH below 7.2 often signals complex infections or malignancy, guiding the decision for therapeutic drainage or chest tube placement. Clinicians must integrate these laboratory findings with patient history and imaging to determine the most effective management strategy for persistent or symptomatic effusions.