Pleural fluid analysis in a febrile patient with pneumonia shows protein 4.2 g/dL, LDH 380 U/L, and specific gravity 1.024. This effusion is best classified as an exudate because:

• A Inflammation increased vascular permeability, allowing protein rich fluid to escape ✓
• B Reduced plasma oncotic pressure altered Starling forces across the pleura
• C Increased hydrostatic pressure forced low protein fluid into the pleural space
• D Lymphatic obstruction selectively trapped lipid in the pleural cavity

Explanation

An exudate reflects increased microvascular permeability in inflammation and is defined by a specific gravity above 1.020, protein above roughly 3 g/dL and elevated LDH relative to plasma. Transudates result from disturbed Starling forces, as in cardiac failure or hypoalbuminemia, and are protein poor. Chylothorax from lymphatic obstruction contains triglyceride rich lymph, not the cellular protein profile described here.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.