Spontaneous cerebrospinal fluid (CSF) rhinorrhea is rare and usually related to a combination of thinning of the bone and dura and fluctuating intracranial pressure.
CSF rhinorrhea can be associated with idiopathic intracranial hypertension, skull base tumors, neurosurgical and otolaryngology procedures, and trauma.
Trauma with fracture of the anterior skull base is the most common cause of CSF rhinorrhea.
CT and MRI can identify bony defects, whereas cisternography can diagnose occult leaks.
Fluid containing CSF is classically described to make a “halo” or “double-ring” pattern on gauze or linen.
However, this sign is not specific to CSF, as mixtures of blood with saline, tears, or rhinorrhea can also produce halos.
Beta-2 transferrin is a protein found almost exclusively in CSF* thus can be used to diagnose CSF rhinorrhea.
Bottom Line: Beta-2 transferrin is more accurate than the halo sign to identify CSF containing fluid.
* Beta-2 transferrin is found in low concentrations in the perilymph in the cochlea, and aqueous and vitreous humor of the eye
References
Chen GY, Ma L, Xu ML, et al. Spontaneous cerebrospinal fluid rhinorrhea. Medicine (Baltimore). 2018;97(5):e9758.
Sunder R, Tyler K. Basal skull fracture and the halo sign. CMAJ. 2013;185(5):416.
Warnecke A, Averbeck T, Wurster U. Diagnostic relevance of B2-Transferrin for the detection of cerebrospinal fluid fistulas. Arch Otolaryngol Head Neck Surg. 2004;130(10:1178-84.
