Duro-Pleural Fistula Diagnosed by β2-Transferrin

An 81-year-old man was referred for evaluation of a chronic transudative pleural effusion that required 8 therapeutic thoracenteses over 11 months for relief of dyspnea. Extensive lumbar disk surgery had been performed 2 years prior to his onset of dyspnea. The diagnosis of duro-pleural fistula was confirmed by finding the presence of beta2-transferrin in the pleural fluid. The 'water-like' pleural fluid had a total protein of <1 gm/dl, an LDH of 92 IU/l, a glucose of 101 mg/dl, and pH of 7.55. beta2-Transferrin has a sensitivity approaching 100% and a specificity of 95% in identifying CSF leaks from head trauma. To our knowledge, this is the first report of beta2-transferrin in pleural fluid from a duro-pleural fistula.