What is a cerebrospinal fluid (CSF) leak?
Cerebrospinal fluid (CSF) is a watery fluid that circulates through the brain’s ventricles (cavities or hollow spaces) and around the surface of the brain and spinal cord. A CSF leak is a condition that occurs when the CSF leaks through a defect in the dura or the skull and out through the nose or ear.
A CSF leak results from a hole or tear in the dura, the outermost layer of the meninges. Causes of the hole or tear can include head injury and brain or sinus surgery. CSF leaks may also occur after lumbar puncture, also called a spinal tap or spinal anesthesia. Spontaneous CSF leaks can also occur for no known reason.
Symptoms of a cerebrospinal fluid (CSF) leak:
When a CSF leak occurs, it may cause any or all of the following symptoms:
- nasal drainage
- visual disturbances
Diagnosis of a cerebrospinal fluid (CSF) leak:
Diagnosing a CSF leak includes an analysis of the nasal fluid for a protein called beta-2 transferrin which is most only found in cerebrospinal fluid. CT and MRI scans may also be require to determine the location and severity of the leakage.
Two further diagnostic tests may also be performed to assist in the diagnosis of the CSF leak: a coronal CT cisternogram and a pledget study.
A pledget study involves placing small cotton pads (called "pledgets") into the nose. This test is used to confirm the presence of a CSF leak, although it cannot determine the exact location of the leak. To determine the exact location of the leak, a CT cisternogram would be performed. A CT cisternogram involves using a contrast injected into the spinal fluid through a spinal tap and then performing CT scans. This test identifies the exact location of the CSF leak and the pathway of the drainage into the nose.
Treatment for a cerebrospinal fluid (CSF) leak:
Because of the risk of meningitis, surgery (usually endonasal endoscopic surgery) is recommended.