N.B. after TBI, nasal mucosa may be swollen – rhinorrhea is delayed (do not confuse with posttraumatic rhinitis)
rhinorrhea – salty taste in mouth.
point of external leakage is poor guide to site of fistula (e.g. CSF may enter ear but leave nose via Eustachian tube).
Differentiation from local bleeding without CSF leak:
ring (halo) test - drop of nasal discharge is placed on piece of filter paper* – CSF (less dense than blood) migrates further on paper than blood – CSF is seen as large transparent ring surrounding central blood clot.
*but may be seen spontaneously on pillow
pure bleeding usually stops in 1-2 days.
Differentiation from nasal secretions: CSF rhinorrhea is clear fluid, tends to be profuse (particularly when bending forward in morning)
glucose concentration: inCSF ≥ 30 mg/dl(in lacrimal secretions / nasal mucus < 5 mg/dl); e.g. CSF tests positive for glucose using Dextrostix.
β2-transferrin assay (present in CSF) - most accurate diagnostic test for CSF!
occult / intermittent CSF rhinorrhea – ENT may see nasal mucosal maceration.
injection of radionuclide (e.g. 99mTc DTPA) into CSF → tampons are placed in each nostril → assessment of uptake by tampons - CSF rhinorrhea is diagnosed when tampon is impregnated with at least twice radioactivity of control tampon in opposite nostril (in presence of intact septum).
Fistulės vietai nustatyti anksčiau buvo naudojamos dažo medžiagos į CSF (metileno mėlis*, fluoresceinas, fenolsulfonftaleinas, indigokarminas), tačiau jos veikia toksiškai ir šiuo metu nebenaudojamos.
overpressure CT cisternography (with metrizamide) - instillation (via LP) of water-soluble contrast into CSF → temporarily occlude both jugular veins for 4-5 min to encourage active leakage → CT in coronal plane with patient placed prone* → contrast medium in sinuses or nasal cavity.
Pressure dressing (does not work for posterior fossa) and wound resuturing if CSF leaks externally (but CSF may find alternate means of egress, e.g. via rhinorrhea).
Local antibiotics (e.g. levomicetino milteliai į ausį); prophylactic antibiotics are started after 7th day of rhinorrhea (many cases arrest spontaneously within 7 days).
N.B. routine prophylactic antibiotics lead to selection of resistant organisms → drug-resistant meningitis.
If CSF leak still persists for > 12-48 hours → reduce CSF pressure by:
multiple lumbar punctures*
continuous / intermittent drainage via lumbar drain* (at the end, clamp drain for 24 hrs – if no leak, remove drain)
permanent diversion by indwelling shunt (in case of coexisting hydrocephalus).
*remove 50-400 mL in any given 24-hour period (e.g. 10 mL/h)
Progressive diminution of level of consciousness (during CSF drainage) - possibility of pneumocephalus!
rhinorrhea is less likely (80%) to arrest spontaneously than otorrhea (95%)
Some surgeons observe drainage for 2 days, others use as many as two 5-day trials of continuous lumbar drainage; if unsuccessful → operation: craniotomy with reapproximation of torn dura, suturing fascia / pericranium / muscle autografts to reinforce closure.
skull base dura is thin and difficult to repair (esp. dura overlying cribriform plate - olfactory nerves travel through it).
Geriau yra užsiūti kietojo dangalo defektą ekstraduraliai, tačiau defektą lengviau surasti intraduraliai.
If everything fails – place VP shunt.
if there is no external CSF leak, may observe CSFomas (pseudomeningoceles) – many disappear over several months.
Bibliography see p. S50
Viktor’s Notes℠for the Neurosurgery Resident
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