INTRODUCTION: Cerebral spinal fluid (CSF) leak has been reported as a cause of pleural effusion. CSF leaks are typically caused by incidental or surgical trauma. Fistulas may result in rapid accumulation of large effusions due to the relative positive pressure of the spinal fluid in comparison to the negative intrapleural pressure. Beta-2 transferrin has been shown to have a high sensitivity and specificity for documenting CSF leak, and it has been used as a diagnostic tool in pleural effusions.
CASE PRESENTATION: We describe a case of a 71-year-old-man who presented with a massive pleural effusion associated with dyspnea. The effusion was discovered on chest radiograph 17 days after a posterior cervical decompression of C3-C6 spinal stenosis performed for progressive myelopathy. Initial thoracentesis was performed both therapeutically and diagnostically. Pleural fluid analysis results are shown in Table 1. Subsequent chest tube drainage was performed concomitantly with closed pleural biopsies. Biopsy pathology was consistent with nonspecific inflammation and tissue cultures were negative. Once the effusion was drained and the patient's dyspnea improved, the chest tube was removed. Following the patient's clinical improvement and discharge to a skilled nursing facility the positive pleural fluid beta-2 transferrin result became available, suggesting a communication between the CSF and the pleural space.
DISCUSSIONS: CSF-pleural fistulas have been shown to result in large pleural effusions. Surgical procedures in the upper thorax or in the paravertebral area of the upper thoracic region of the spine have been associated with such leaks. To our knowledge there have been no previously reported cases following a procedure performed at the C3-C6 level. The typical fluid description for a CSF-pleural fistula effusion has been clear, with low nucleated cell count, and transudative range protein. There have been prior case reports with exudative range fluid values and varying cell counts. It has been previously postulated that coexisting pleural processes may influence the composition of the fluid. Beta-2 transferrin is a transferrin isoform unique to the CSF and inner ear perilymph fluid. It is believed that the desialation of the more ubiquitous isoform beta-1 transferrin occurs only by the action of cerebral neuraminidase. Beta-2 transferrin has been shown to have a high sensitivity and specificity for detecting CSF leaks in the setting of head trauma, but the test characteristics are unknown for CSF-pleural fistulas as the literature is limited to case reports.
CONCLUSION: We have described what we believe to be a CSF leak complicating a cervical spine procedure. This leak resulted in a rapidly accumulating exudative and eosinophilic effusion. The considerable rarity with which CSF-pleural fistulas occur requires a high index of suspicion for this complication in the proper clinical setting. Although typically described as clear transudative fluid collections, CSF-pleural fistula effusions have been reported to have varying qualities on fluid analysis. Beta-2 transferrin has been used for the detection of CSF in a pleural effusion. There are case reports of confirmed CSF-pleural fistula effusions with documented negative beta-2 transferrin. However, there has been no report of a documented false positive test. Our patient's effusion resolved with chest tube drainage and was therefore not evaluated further. Beta-2 transferrin may be a useful tool in the diagnosis of CSF-pleural fistulas. Treatment should be tailored to the individual patient. Drainage of the effusion alone or surgical correction may be needed. Patients should be monitored closely for signs of central nervous system sequelae, including meningitis, during their recovery.
DISCLOSURE: Jason Gunn, None.