Csf = cerebrospinal fluid; rhinos = nose; rhoia = flowing
- What is CSF Rhinorrhea?
- Composition of CSF
- Incidence of CSF Rhinorrhea
- Causes of CSF Rhinorrhea
- Location of CSF Leak
- Risks of CSF Rhinorrhea
- Signs & Symptoms of CSF Rhinorrhea
- Investigations of CSF Rhinorrhea
- Differential Diagnosis Allergic Rhinorrhea Vs CSF Rhinorrhea
What is CSF Rhinorrhea?
CSF rhinorrhea is the leakage of CSF (Cerebrospinal fluid is the protective fluid present in subarachnoid space that surrounds the brain) from its intracranial location through the nose. This is caused due to disruption of the barrier between cranial fossa and nasal cavity.
Composition of CSF
The composition of CSF is a mixture of water, electrolytes (Na+, K+, Mg2+, Ca2+, Cl-, and HCO3-), glucose (60-90% of blood glucose), amino acids, and various proteins (20 Mg%).
CSF is colorless, clear fluid that is typically devoid of cells such as polymorphonuclear cells and mononuclear cells (< 5/µL).
Incidence of CSF Rhinorrhea
Most cases of the CSF Rhinorrhea are caused due to trauma and surgical procedures.
2-9% reported cases of nasal trauma are complicated by CSF rhinorrhea, among which 25% of these cases involve paranasal sinuses.
Post traumatic CSF leak is immediate in the majority of the cases, when delayed it appears within 3 months in 95% of cases.
16% of CSF leak is due to surgeries in the nose, para nasal sinuses and skull base.
5% of cases occur spontaneously.
Causes of CSF Rhinorrhea
Occurrence of CSF rhinorrhea could be either,
Traumatic CSF Rhinorrhea
In traumatic situations CSF Rhinorrhea could be accidental (surgical mishaps, traffic injuries etc.,) or due to drugs that are used to treat pre-existing medical conditions where it could be acute or delayed depending upon the cause.
Non-Traumatic CSF Rhinorrhea
Generally CSF Rhinorrhea is caused due to high pressure conditions such as Hydrocephalus, direct invasion of the tumor or indirectly due to increase in intracranial pressure.
In the case of normal pressurised conditions CSF Rhinorrhea may be caused by Congenital disorders, Osteomyelitic lesions, Facial atrophy or Idiopathic.
Spontaneous CSF Rhinorrhea
Some patients can develop spontaneous CSF rhinorrhea, this may be due to idiopathic intracranial hypertension (IIH) which is also known as pseudotumor cerebri where high pressure inside the skull eventually creates small holes between the nose and the area where the brain rests.
Spontaneous CSF rhinorrhea is also associated with the presence of meningoceles or encephaloceles.
The causes of spontaneous CSF rhinorrhea is unknown, but the condition may be associated with obesity and high blood pressure.
Location of CSF Leak
Leakage of CSF is often seen in the floor of anterior cranial fossa at the levels of cribriform plate which may be either anteriorly or posteriorly placed.
Anteriorly placed leaks are in the frontoethmoidal junction and posteriorly placed leaks in the sphenoethmoidal junction and sphenoid sinus.
Risks of CSF Rhinorrhea
Risks of CSF rhinorrhea include the possibility of developing meningitis, because of this, it’s important to see your doctor as soon as possible.
Medical treatment with antibiotics haven’t shown any reduction in the risks associated and aren’t recommended on a regular basis unless the signs of meningitis appear.
Signs & Symptoms of CSF Rhinorrhea
General clinical features of CSF Rhinorrhea include,
- Recurrent watery clear non-sticky discharge from the nose (Often Unilateral). Positional change or jugular compression can increase the flow of the discharge. Reservoir sign is a sudden rush of fluid, which occurs after being brought to an upright position with the neck flexed by being supine for some time.
- Hyposmia and anosmia in 80% of cases.
- Headache in 20% of cases
- Other symptoms such as nasal congestion, ringing in the ears, dizziness and change in vision (blurred vision, double vision, visual field defects) can also be noticed.
- Halo sign (target sign or double ring sign), when the CSF Rhinorrhea is blood-stained and dries out, a central bloodstain surrounded by a clear ring is seen.
These symptoms also occur in multiple common conditions and so should be evaluated by an ENT specialist if they are not easily explained or do not clear up on their own in a week or so.
Any delay in the evaluation of these symptoms might lead to serious complications such as meningitis.
Investigations of CSF Rhinorrhea
Diagnostic nasal endoscopy is useful to locate the site of the CSF leak i.e.middle meatus, superior meatus or sphenoethmoidal recess.
Contrast CT/MRI scans are carried out. A better view of the CSF leak is revealed when a CT scan is taken (after 3 hours) using contrast given intrathecally by lumbar puncture.
Immunoelectrophoretic identification of β2 transferrin is the most widely used test.
An increased estimation of 30mg/ml of glucose content in the nasal discharge is significant
Injection of color dye such as methyl blue, indigocarmine, toluidine blue in subarachnoid space reveals defects in cranial fossa.
Radioactive isotope injection and Intrathecal fluorescein injection is also used to disclose the site of CSF Leak.
Metrizamide computer tomographic cisternography (MCTC) is used to locate the leak site.
HRCT nose and PNS coronal, sagittal and axial cuts are also useful for CSF leak diagnostic purposes.
Glucose oxidase impregnated strips are not reliable, as false positive tests may be given by lacrimal and nasal mucosal secretions.
Differential diagnostic tests,
Wet handkerchief test, a kerchief is placed near the nose to notice drainage and when the drainage dries up and the handkerchief becomes stiff, it is considered as a negative in CSF Rhinorrhea, while positive in cases such as allergic rhinorrhea .
Differential Diagnosis Allergic Rhinorrhea Vs CSF Rhinorrhea
|Allergic Rhinorrhea||CSF Rhinorrhea|
|Clinical features||Features of allergies like sneezing,nasal block and itching are present||These associated features are absent|
|Etiology||allergen||Traumatic (accidental or iatrogenic) spontaneous|
|Discharge||Mucous like or clear,which is not increased by raising intra-abdominal pressure and intracranial pressure but discharge can be sniffed back||Thin and watery which increases on bending forwards and cannot be sniffed back|
|Handkerchief Test||Discharge is dried up and cloth becomes stiff||No such effect|
|Halo Sign||Absent||Present in traumatic cases|
|Lab||Sugar content is less than 10 mg/ml, β2 transferrin is absent||Sugar content is more than 30 mg/ml, β2 transferrin is present|
|CT scan||Normal skull base||Shows bony dehiscence in anterior skull base|
In traumatic or spontaneous CSF Rhinorrhea, the following preventive treatments are taken,
- Prophylactic antibiotics
- Bed rest in head up position
- Avoid coughing,sneezing and nose blowing that increases pressure
- Mild laxative to prevent constipation
- Repeated or continuous lumbar puncture
- Traumatic cases heal with medical management (diuretics,mannitol)
Endoscopic approach is persuaded via transnasal route. The mortality and morbidity in this approach is absolutely minimal in comparison to intracranial approach. It gives a high success rate of closure.
This Approach can be done in very elderly patients also without having any fear of developing cerebral anoxia.That is why this approach is gaining more and more popularity among surgeons and also with patients.
CSF rhinorrhea can be adequately managed by transnasal endoscopic approach. However, facilities like a good radiologist with CT and MRI scan facilitates and adequate surgical expertise is required.
Extracranial Surgical Repair
In the Extracranial surgical repair the middle turbinate is resected inferolaterally (a concha bullosa is excised on its lateral aspect) for a better visualisation of middle meatus and a infundibulotomy is performed by resecting the uncinate process.
Bulla is identified and opened in the same way as done in endoscopic sinus surgery.
The anterior ethmoidal cells are exenterated completely to expose the dome of the ethmoid.
The anterior ethmoidal artery is identified. If the posterior ethmoidal and the sphenoid are the sites of leakage, they are opened further, keeping the ethmoid as a landmark.
Anesthesiologists usually hyperventilate the patient and raise the CSF pressure which facilitates in identifying the CSF leak.
The dura is exposed further at the site of the leak.
A piece of temporalis fascia harvested from the post auricular region is placed over the defect which is anchored between dura and bone.
The graft is further covered with subcutaneous fat, which is well supported further with surgical and gel foam.
The middle meatus then packed with BIPP (BISMUTH IODINE PARAFFIN PASTE) pack.This can be removed on 10th postoperative day. The cavity should be reinspected after 1 month.
CSF pressure should be controlled during the postoperative period till the healing is complete.
Neurosurgical approach is the intracranial approach through bicoronal craniotomy. This is done through a bicoronal craniotomy or mini craniotomy. Repairing of the defect is done transcranially by using bone and fascia lata graft.
CSF Rhinorrhea is the leakage of cerebrospinal fluid through the nose caused by trauma or during surgical mishaps and is presented by clear water discharge which is subsided by general measures and surgical treatment.