Cerebrospinal fluid rhinorrhea and otorrhea: A multimodality imaging approach

Abstract

Cerebrospinal fluid (CSF) leaks are extracranial egress of CSF into the adjacent paranasal sinus or tympanomastoid cavity due to an osteodural defect involving skull base. It can be due to a multitude of causes including accidental or iatrogenic trauma, congenital malformations and spontaneous leaks. Accurate localization of the site of the leak, underlying causes and appropriate therapy is necessary to avoid associated complications. In this paper relevant anatomy, clinical diagnosis, imaging modalities and associated findings are discussed along with a brief mention about management.

ACR Appropriateness Criteria® Head Trauma: 2021 Update

“…Most cases present in the first 48 hours after injury (80%), with nearly all cases by the 3-month mark (95%) [58]. Clear watery nonmucoid fluid drainage from the nose or ear can be tested for the presence of b2-transferrin or b2-trace protein to confirm a CSF leak (note: b2-trace has sensitivity and specificity approaching 100% in patients without chronic renal failure) [64]. Despite the often acute presentation, surgical repair with preoperative neuroimaging localization of a traumatic CSF leak may be delayed or reserved for patients who fail 1 to 2 weeks of conservative management (eg, bedrest with head elevated 30 ) [63].…”

“…CT cisternography is highresolution CT (HRCT) of the skull base after a lumbar puncture for intrathecal administration of approximately 10 mL of an iodinated contrast agent (eg, 3 g of iodine). Its sensitivity for contrast leakage from the subarachnoid space into the sinonasal or tympanomastoid cavities depends on the rate of CSF leak and ranges between 85% and 92% in patients with an active leak versus 40% in patients with an inactive or intermittent leak [64]. Noninvasive noncontrast HRCT has a high sensitivity of 84% to 95% and has replaced traditional use of minimally invasive contrastenhanced CT cisternography in the initial imaging evaluation of suspected CSF leak with laboratory confirmation [64,65].…”

“…Its sensitivity for contrast leakage from the subarachnoid space into the sinonasal or tympanomastoid cavities depends on the rate of CSF leak and ranges between 85% and 92% in patients with an active leak versus 40% in patients with an inactive or intermittent leak [64]. Noninvasive noncontrast HRCT has a high sensitivity of 84% to 95% and has replaced traditional use of minimally invasive contrastenhanced CT cisternography in the initial imaging evaluation of suspected CSF leak with laboratory confirmation [64,65]. No additional preoperative neuroimaging is necessary when a single skull base defect is identified on the HRCT; when there are multiple potential CSF leak sites, then follow-up CT cisternography is indicated [58,64].…”

“…Noninvasive noncontrast HRCT has a high sensitivity of 84% to 95% and has replaced traditional use of minimally invasive contrastenhanced CT cisternography in the initial imaging evaluation of suspected CSF leak with laboratory confirmation [64,65]. No additional preoperative neuroimaging is necessary when a single skull base defect is identified on the HRCT; when there are multiple potential CSF leak sites, then follow-up CT cisternography is indicated [58,64].…”

“…CT Maxillofacial. HRCT is the most useful study in the initial imaging evaluation of suspected CSF leak with laboratory confirmation (ie, positive for b2-transferrin or b2-trace) [58,64,66]. Thin-section bone algorithm images of the skull base with multiplanar reformation may be requested as a maxillofacial CT for CSF rhinorrhea versus a temporal bone CT for CSF otorrhea.…”