Cerebrospinal fluid leak

Background

CSF leaks are associated with a high risk of meningitis (10-25%, depending on etiology and chronicity)
May be spontaneous (may be a cause of idiopathic intracranial hypotension), traumatic, or post-neurosurgical
Spontaneous leaks are more common in overweight or obese patients

May follow head trauma or skull-base surgery
Symptoms of IIH, including headache, visual defects, and pulsatile tinnitus
Symptoms of low ICP, including orthostatic headache and nuchal rigidity
CSF rhinorrhea
- Typically unilateral and watery
- Typically triggered by changes in posture

Beta-2 transferrin or beta trace protein, which is positive in CSF
- Best way to differentiate CSF from normal rhinorrhea
High-resolution CT of the sinuses and skull base without contrast
- Looking for defects in lateral lemella/olfactory cleft/ethmoid roof, roof of the lateral recess of the sphenoid sinus, supraorbital ethmoid roof/frontal sinus posterior table, and planum sphenoidale and posterior wall of sphenoid sinus and temporal bone
High-resolution MRI to assess the area of suspected leak as well as signs of IIH
Imaging may show suggestive signs: empty sella, arachnoid pits, erosion of skull base, widening of the subarachnoid space around the optic nerves, tortuous optic nerves, posterior globe flattening, dilated Meckel cave
May need MRV (or CTV) to exclude a transverse venous sinus stenosis

Per consensus guidelines, the following assessments are recommended:
- All patients with suspected CSF rhinorrhea should have ENT exam including nasal endoscopy and otologic exam
- May benefit from ophthalmologic assessment for papilledema as well as assessment of visual fields
Current IDSA guidelines1 recommend:
- No routine prophylactic antibiotic in patients with basilar skull fractures and CSF leak
- Surgical repair if leak lasts more than 7 days
- Pneumococcal vaccination
International consensus guidelines suggest:
- If CSF rhinorrhea is proven, they should undergo closure
- Patient should be counselled on risk of meningitis
- No routine prophylactic antibiotics

^ Allan R. Tunkel, Rodrigo Hasbun, Adarsh Bhimraj, Karin Byers, Sheldon L. Kaplan, W. Michael Scheld, Diederik van de Beek, Thomas P. Bleck, Hugh J.L. Garton, Joseph R. Zunt. 2017 Infectious Diseases Society of America’s Clinical Practice Guidelines for Healthcare-Associated Ventriculitis and Meningitis*. Clinical Infectious Diseases. 2017;64(6):e34-e65. doi:10.1093/cid/ciw861.