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.


• 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


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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