Pathology | Aetiology | Diagnostic tests |
---|---|---|
Haemothorax | Frank blood in the pleural space, normally as a result of trauma | Haematocrit PF level of >0.5 that of the serum14 |
Chylothorax (Fig 1) | Damage to the thoracic duct causing a chyle leak into the pleural space | Presence of chylomicrons is diagnostic |
Triglyceride levels of >110 mg/dL (>1.24 mmol/L)16 | ||
Pseudochylothorax | High levels of cholesterol, common in tuberculous and rheumatoid related effusions | Presence of cholesterol crystals |
Cholesterol/triglyceride level of >117 | ||
MPE | Fluid accumulation caused by primary or secondary malignancies. | PF cytology or pleural biopsies showing malignant cells |
Pleural infection | Frank pus or infected fluid in the pleural space | Visual confirmation of pus or positive microbiological culture (including Mycobacterium tuberculosis) |
Urinothorax | Due to traumatic damage to the urinary system or obstructive uropathy | PF/serum creatinine ratio of >1 with a pH lower than 7.3018 |
Pancreatic disease | Any damage to the pancreas can result in a pleural effusion | PF amylase >110 U/L (only diagnostic if there is a predominant pancreatic isoenzyme profile)19 |
MPE = malignant pleural effusion; PF = pleural fluid