Cerebrospinal Fluid Leaks and Encephaloceles

primary (spontaneous) and secondary; Gendeh et al. classified them into congenital, acquired, and spontaneous.


Spontaneous Leaks


• The prevalence in various series varies from 3% to 36%.


• 75% of these leaks are associated with raised ICP


• 50% to 100% of these leaks have associated encephaloceles; likely due to the long-standing nature of these leaks


• The leaks are notoriously difficult to seal, and are associated with 25% to 87% recurrence rate.


Encephaloceles


• Herniation of intracranial contents through bony defects


• Meningocele involves herniation of dura only.


• Encephalocele (more accurately termed meningoencephalocele) involves herniation of dura and brain.


• Encephalocystocele involves herniation of dura, brain, and part of the ventricular system.


• A relatively larger skull base defect can cause CSF leaks with herniation of the above.


• These herniated materials are considered non-functioning, and are to be surgically removed prior to the repair of the skull base defect.


• Congenital encephaloceles: three subtypes


1. Occipital: most common; ~75% of cases


2. Sincipital (frontoethmoidal): ~15% of cases; nasofrontal (most common subtype), nasoethmoidal, nasoorbital


3. Basal: ~10% of cases; transethmoidal (most common subtype), sphenoethmoidal, transsphenoidal, sphenoorbital


DIAGNOSIS


Signs and Symptoms


• Patient often have few symptoms until a significant leak occurs.


• They may complain of clear, runny nasal discharge, which is often unilateral, commonly associated with headaches.


• This is increased when the patient bends over (reservoir sign) or increases his or her intracranial pressure with Valsalva-like maneuvers.


• The expansion of a nasal encephalocele with compression of the internal jugular vein or with crying/straining is known as Furstenberg’s sign; this is not present in gliomas or dermoids as there is no associated patent CSF tract.


• A central nervous system complication—for example, meningitis or intracranial abscess—may be the first presentation for some patients.


Diagnostic Tests


• Clinical: halo sign; only in traumatic injuries with mixed CSF and bloody rhinorrhea; a drop of the rhinorrhea will separate into two haloes (central ring of blood and an outer ring of CSF) on a filter paper


• Clinical: diagnostic endoscopy with maneuvers like bending forward and Valsalva


• Biochemical: presence of glucose (≥5 mg/dL); absent in nasal mucus


• Biochemical: β2 transferrin (sensitivity 99% and specificity 97%), a protein found in CSF, aqueous humour, and perilymphatic fluid, but not in blood or nasal secretions; the presence of cirrhosis or congenital protein anomalies increases false positive


• A newer assay, β trace protein appears very promising (in reports, sensitivity and specificity reaches 100%).


• High-resolution axial CT with coronal and sagittal reconstructions

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Jul 20, 2019 | Posted by in OTOLARYNGOLOGY | Comments Off on Cerebrospinal Fluid Leaks and Encephaloceles
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