Cerebrospinal fluid rhinorrhoea is the leakage of cerebrospinal fluid from the subarachnoid space into the nasal cavity through a defect in the dura, bone, and mucosa. Common causes include head trauma, intranasal surgery, and skull base tumors. Diagnosis involves examining nasal fluid for beta-2 transferrin and imaging tests like CT and MRI to locate the leak site. Treatment is usually surgical to repair the defect, with an endoscopic approach being preferred over craniotomy in most cases. Success rates are high but raised intracranial pressure can cause repairs to fail and may require additional neurosurgical procedures.

1. Cerebrospinal fluid rhinorrhoea
Definition: cerebrospinal fluid rhinorrhoea is the leakage of the CSF from the subarachnoid space
into the nasal cavity due to a defect in the dura, bone& mucosa. The orgin of the fluid may be from
the anterior, middle or posterior cranial fossae. The fluid may be escape directly into the nose from a
defect in the anterior cranial fossa, either via the frontal sinus, ethmoid sinuses or sphenoid sinuses
or from the cribriform plate.
A leak from the middle or posterior cranial fossa usually communicates with the nasal cavity via the
mastoid cavity & middle ear cavity through the Eustachian tube.
Physiology
CSF fluid is produced by the choroid plexus in the lateral , third & fourth ventricles of the brain. Total
volumne about 125ml.
Aetiology
The most common surgical causes are headlight intranasal surgery, endoscopic sinus surgery,
craniotomy, transphenoidal hypophysectomy or simple headlight polypectomy.
The onset of CSF rhinorrhoea may be delayed from time of the initial insult. The possible reasons for
this are the delayed resolution of a haematoma at a fracture site or intracranial pulsation causing
herniation eventually separation of the dura through a nonheal fracture site.
Causes of CSF rhinorrhoea
Idiopathic Trauma Inflammatory Neoplasm
Cause is unknown,
possibly intermittent
increases in
intracranial pressure.
Intranasal surgery
endoscopic sinus
surgery, skull base
fractures, transcranial
approaches including
surgery of the middle
& posterior cranial
fossa.
Erosive lesion:
mucocoeles. Polypoid
disease,cystic fibrosis,
fungal sinusitis,
osteomyelitis.
Neoplasm invading the
skull base.
Management
The majority of the patient will present with intermittent or continuous rhinorrhoea. This is usually
unilateral but may be bilateral. There is often history of previous surgery.
Nasoendoscopy examination should be performed on ther out patient clinic. Otoscopy should be
performed to cxclude a middle ear effusion as a defect in the middle or posterior cranial fossa can
be the origin of the CSF rhinorrhoea. The investigations include:

2. 1.Laboratory investigation of rhinorrhoea fluid.
2. Imaging
3.Intrathecal dyes &markers.
1.Laboratory investigations
Beta -2 transferrin is a protein involved in ferrous ion transport & it is also found in perilymph &
aquous humour. Only few drops of CSF is required. The physician should aware that ceratin
conditions abnormal transferring metabolism,& thus the beta-2 transferrin can appear in the blood,
which could potentially lead to a false positive result. These are chronic liver disease, inborn errors
of glycogen metabolism, neurophyschiatric disease & rectal carcinoma.
2. Imaging
With the advent of high resolution CT , MRI & fluorescein lumber puncture, these modalities now
form the mainstay of investigation.
High resulation coronal scans (1-2 mm slices) can offer detection in up to 84% of cases. Axial views
are helpful in detecting leaks from the posterior wall of frontal sinus & sphenoid sinus.
3. Intrathecal dyes & markers
Fluorescein dye commonly use today. It can be exceedingly helpful either preoperatively in
outpatient setting intraoperatively or both. Typically .25ml of 5% fluorescein is mixed with 10ml of
CSF from a routine lumber puncture. The mixture is introduce via a polymedic pencil-point spinal
needle & the patient is placed in the trendelenberg position for approximately for an hour. Then
endoscopic examination is performed, fluorescein can be seen coming out from the defect. The use
of blue filter on the endoscope light source can be increase the ease of detection.
If at operation , fluorescein is not seen then the anaesthetist can temporarily raise the intracranial
pressure by making the patient cough on their endotracheal tube tube as this will often cause the
fluorescein to appear through the leak.
Complication using a fluorescein lumber puncture have been described but with higher
concentration than recommended here. They includes knee & ankle clonus, seizure, opisthonos &
cranial nerve defect. None of the complications have been permanent & their occurance is
extremely rare. Previous spinal surgery may prevent the use of fluorescein lumber puncture.
Antibiotics
There is debate as to whether antibiotic prophylactic should be prescribed in patients with known
CSF rhinorrhoea. One meta analysis concluded that there is a significant reduction in the incidence
of meningitis with prophylactic antibiotic therapy.
Other go further & would not recommended prophylaxis in absence of infection as this can lead to a
change in nasopharynx flora , potentially causing a partially treated or gram-negative meningitis.

3. Surgery
Traditionally two approaches are available a craniotomy & an extradural external approach. With the
development of endoscopic sinus surgery, this is now the the approach of choice with excellent
success rate & minimal surgical morbidity (exception associated with malignancy).
1.Intracranial approach
2. Extracranial approach
This remain the method of choice for assessing most leaks of the posterior wall of the frontal sinus
that defy an endoscopic approach.
Via an external ethmoidectomy for access to the cribriform plate & fovea ethmoidalis.
Via transmastoid for defects in the tegmen& petrous temporal bone.
Via transseptosphenoidal for access to the sphenoidal sinus .
Via a coronal or eyebrow incision to the frontal sinus using an osteoplastic flap.
In frontal & sphenoidal sinuses the mucosa can be removed, the decfect patched with fascia & the
sinus can be can be obliterated by packing with fat. Nasal septum or turbinate can be used to
support the graft.
Extradural approach does have the advantage that it minimizes the incidence of intracranial
complications.
3. Endoscopic surgery
All techniques require accurate localization of of the leak intraoperatively. The edge of the defect are
then freshened. The graft material is then placed into the defect as an underlay graft where possible.
Majority of surgeons support their graft using nasal packing such as oxidized cellulose followed by a
bismth iodoform paraffine paste pack (BIPP). The grafts are nasal mucosa flap or free nasal mucosal,
which may be a composite graft incorporating turbinate bone ,conchal or septal scartilage, temporal
fascia & fascia lata. Nearly all use antibiotic cover for the procedure.
The patient should be advised not to blow their nose, to sneeze with their mouth open to avoid any
abrupt increase in intracranial pressure.
The supporting pack should be removed 7 to 10 days after surgery.
Reason to failure
Raised intracranial pressure is the most common reason for failure to repair a CSF leak. The raised
intracranial pressure due to stenosis of sylvian duct or benign raised intracranial pressure mainly
occur in obese young women with vague menstrual irregularities. A raised intracranial pressure is far
more prevalent in patients with a spontaneous CSF leak. If imaging shows dilated cerebral ventricles
then a neurosurgical procedure to lower the pressure such as shunt, should be performed at the
time of repair of the leak.