Table 5

Other important causes of pleural effusions

ConditionClinical featuresPleural fluid characteristicsSpecial investigations and management
Early post-CABG pleural effusion158Occur within 30 days of CABG.
Left > right.
Most small and asymptomatic.
Prevalence 89% at 7 days postoperatively
Bloody (haematocrit >5%).
Often eosinophilic
Only perform diagnostic aspiration if the patient is febrile, complains of pleuritic chest pain or the effusion is very large.
Most settle spontaneously
Late post-CABG pleural effusion159Occur >30 days post-CABG.
Left > right.
May be large and associated with dyspnoea
Diagnostic aspiration to exclude other causes and confirm the diagnosis.
Repeated therapeutic thoracentesis usually successful for symptomatic effusions.
Urinothorax160Due to obstructive uropathy.
Urine tracks through the retroperitoneum to the pleural space.
Pleural fluid creatinine > serum creatinine.
Low pH
Usually resolves with relief of the renal obstruction
Ovarian hyperstimulation syndrome161Life-threatening reaction to ovulation induction (hCG or clomiphene).
May be pleural effusion alone (usually right sided) or whole syndrome with:
massive ascites, renal and hepatic failure, thromboemboli and ARDS
Exudate with both protein and LDH in exudative rangeRepeated therapeutic aspirations often required to relieve dyspnoea
Lymphoma-related pleural effusion162Effusion may be associated with mediastinal lymphadenopathy on CT but often there are no clinical features to distinguish from other causes of pleural effusionExudate.
Positive cytology in around 40%.
Chylothorax in around 15%
Pleural fluid flow cytometry and cytogenetics may be useful.
Thoracoscopic pleural biopsies are often negative but required to exclude other causes if diagnosis unclear
  • ARDS, adult respiratory distress syndrome; CABG, coronary artery bypass graft; hCG, human chorionic gonadotrophin.