This is a very interesting question. Unless you have had a traumatic injury to the head or face, have chronic sinus disease or have been irrigating your nose with normal saline (salt water) it is highly unlikely that this fluid is a sign of a serious condition (see the second statement regarding benign causes, below in bold). However, the type of drainage you describe can also be a sign of leakage of the fluid that surrounds the brain and in 10% of such cases, there is no history of trauma.
The information copied below is from Flint-Cummings Textbook on Diseases of the Ear, Nose and Throat. I provide it so that you can share it with your doctors, either with your primary care physician (PCP) and/or an ENT Specialist recommended by your PCP.
While this will probably turn-out to be nothing serious, you and your doctors should not assume this to be the case. Such drainage should not be ignored. A most direct approach to diagnosis would be to send a specimen of the drainage to the lab for a determination of what type of fluid it is, including testing for CSF.(see Confirmation, below).
CHAPTER 54 – Cerebrospinal Fluid Rhinorrhea
Martin J. Citardi,
• Cerebrospinal fluid rhinorrhea may be classified as traumatic (>90%) or nontraumatic (<10%). Approximately 80% of all traumatic leaks occur in the setting of accidental trauma, and the remaining traumatic leaks occur after neurosurgical and rhinologic procedures. Nontraumatic etiologies include neoplasms and hydrocephalus.
The differential diagnosis for watery rhinorrhea includes allergic rhinitis, vasomotor rhinitis, and retained nasal saline irrigation fluid as well as cerebrospinal fluid otorrhea that is draining through the eustachian tube.
• Idiopathic nontraumatic cerebrospinal fluid rhinorrhea has been linked with elevated intracranial pressure. Numerous studies have confirmed an association of this entity with both benign intracranial hypertension and empty sella syndrome.
• Clinical presentation includes unilateral watery drainage with a characteristic metallic or salty taste, often in the clinical setting of possible etiologic factors.
• Confirmation of a cerebrospinal fluid leak can be achieved through detection of β2-transferrin or β-trace protein in nasal secretions.
• Cisternogram studies provide diagnosis confirmation and localization information. Both CT cisternography and radionuclide cisternography require lumbar puncture for the administration of tracer agent, whereas MRI cisternography can be achieved solely through specific imaging protocols. Radionuclide cisternography has poor sensitivity and poor spatial resolution. Both CT cisternography and MRI cisternography offer much greater spatial resolution but still require the presence of a relatively large, active leak for reliable detection.
• Endoscopic examination after the administration of intrathecal fluorescein can confirm the diagnosis of a cerebrospinal fluid leak and indicate its location. Dilute fluorescein must be used; serious neurologic sequelae have been reported after higher intrathecal doses of this agent.
• Endoscopic repair has emerged as the preferred modality for most cases of cerebrospinal fluid rhinorrhea requiring operative repair. During endoscopic repair, the leak site is identified and then closed with autogenous graft materials (fascia, free bone graft, fat), allograft (acellular dermal allograft), and xenogeneic collagen dural substitutes, or a combination. A free mucosal graft is typically placed over these materials, and the reconstruction is secured with surgical sealant and resorbable and nonresorbable packing material.
• The role of prophylactic antibiotics remains controversial. Some data suggest that antibiotics should be administered after detection of a cerebrospinal fluid leak, but the data are far from conclusive. Certainly, in the presence of active infection adjacent to the leak site, antibiotics are prudent.
• Traumatic cerebrospinal fluid leaks are likely to resolve with conservative measures (lumbar drainage and bed rest); operative repair is reserved for those cases in which these measures fail or in which massive injury requires urgent formal operative exploration and repair.
• Cerebrospinal fluid leak that is recognized at the time of surgery should be repaired during that procedure. Cerebrospinal fluid rhinorrhea that develops after surgery may be managed conservatively at first, but most cases require operative repair.
• Nontraumatic cerebrospinal fluid rhinorrhea is unlikely to resolve spontaneously. After potential etiologic factors (brain tumor) have been excluded, operative repair is warranted.
Cerebrospinal fluid (CSF) rhinorrhea results from a direct communication between the CSF-containing subarachnoid space and the mucosalized space of the paranasal sinuses. Because it may serve as a path for the spread of bacterial pathogens and other microorganisms, CSF rhinorrhea may lead to meningitis and intracranial infections, which carry significant morbidity even today. In addition, the skull base defect through which CSF drains may provide a route for the development of pneumocephalus and secondary brain compression. Although CSF rhinorrhea is a simple concept, its diagnosis and localization may be problematic; fortunately, contemporary strategies now provide a more direct means of diagnosis and localization. Over the past two decades, the optimal treatment strategy has undergone significant evolution as minimally invasive, endoscopic techniques have gained acceptance and supplanted more traditional techniques requiring external incisions or craniotomy.
CSF rhinorrhea was first reported in the 17th century. In the early 20th century, Dandy reported the first successful repair, which used a bifrontal craniotomy for placement of a fascia lata graft. Although this surgical strategy provided direct access for the repair, reported failure rates were quite high and the procedure entailed the morbidity of craniotomy. In fact, reported recurrent rates were as high as 27%, and in one series only 60% of leaks were successfully repaired.
Extracranial approaches were introduced in the mid-20th century. In 1948, Dohlman presented a patient whose CSF leak was repaired through a standard naso-orbital incision. Several years later, Hirsch reported the successful closure of two sphenoid sinus CSF leaks through a pure endonasal approach. In 1964, Vrabec and Hallberg described the repair of a cribriform defect through an endonasal route. All of these endonasal procedures were performed before the advent of surgical nasal endoscopy.
Endoscopic approaches were introduced and popularized in the 1980s and early 1990s. Both Wigand and Stankiewicz described closure of incidental CSF leaks during endoscopic sinus surgery. In 1989, Papay and colleagues introduced rigid transnasal endoscopy for the endonasal repair of CSF rhinorrhea, and in 1990, Mattox and Kennedy presented another series of cases in which the CSF rhinorrhea was addressed with use of endoscopic visualization. Since then, numerous series have been published,[12-14] and endoscopic repair has emerged as a mainstay of surgical management.