CSF is cerebrospinal fluid that is found around the brain and spinal cord. The brain and spinal cord are covered by 3 layers of membranes or coverings called the meninges.
The meningeal layers are:
- Dura mater
- Arachnoid mater
- Pia mater
The CSF fluid is found in the sub-arachnoid space, i.e., between the arachnoid and pia mater.
CSF rhinorrhea is leaking of this fluid into the nose. This occurs when the fluid drips from the skull into the nose, and drips like water on bending forwards. Typically, the patients will notice this problem when bending forwards while eating or picking up something from the floor. The problem is usually confined to one side. So, if anyone notices clear water dripping from one side of the nose, they need to be careful and meet an ENT specialist to rule out this condition.
The pathway that allows the CSF fluid to drip into the nose will also transmit infections from the outside environment. Through this pathway, infections can enter the skull and cause serious problems like meningitis.
Causes for CSF rhinorrhea:
The list of causes can be:
- Idiopathic (no known cause).
- After surgery of the nose, sinuses, intracranial, ear, etc.
- Following trauma (head injury, road traffic accidents, facial injuries, etc.)
- High pressure leaks following raised pressure inside the skull (intracranial hypertension).
Q1. What can you expect on visiting an ENT specialist with this complaint?
A. You can expect your consultant to ask you certain questions. You will have an examination especially of your ears, nose, and throat. A nasal endoscopy may be performed to examine the interiors of the nose in detail. If the suspicion is strongly towards CSF, you may be recommended to get scans done of the skull (paranasal sinuses and temporal bone).
Q2. What are the different scans used to diagnose CSF leak?
The following scans may be used: CT cisternography - In this procedure, a CT scan of the concerned area is done following an injection of a dye into the subarachnoid space in the lower back area (lumbar puncture).
Those patients who do not want an invasive procedure can undergo an alternative scan in the form of HRCT of paranasal sinuses and temporal bone and correlate it with an MRI (constructive interference in steady state (CISS) imaging).
In most patients having an active leak, these tests will be sufficient to localize the defect and demonstrate the leak.
Q3. What are the treatment options for CSF leak?
If the leak is immediately following trauma, conservative treatment is tried for 2 weeks, which will include medications, bed rest, etc. If the time period is a few weeks following trauma or if the leak is idiopathic, surgical closure of the leak is recommended.
Q4. What are the surgical options available?
Previously, the only option was trans-cranial surgery performed by the neurosurgeons involving opening up of the skull. The introduction of endoscope-guided surgery has allowed the ENT surgeons to get access to the leak sites through the nose, i.e., transnasal endoscopic repair of CSF leaks.