Cerebrospinal Fluid (CSF) Leak
- Cerebrospinal fluid (CSF) is a watery fluid that continually circulates through the brain’s ventricles (hollow cavities) and around the surface of the brain and spinal cord.
- CSF washes out impurities from the brain, transfers nutrients and provides protective cushioning to the brain and spinal cord.
- The fluid is contained by the meninges, a series of protective membranes that surround the brain and spinal cord.
- CSF leaks can cause fluid to leak through the ears, through the nose or into the spinal canal.
- CSF leakage through the ears or nose should be diagnosed and treated quickly and effectively to prevent meningitis, an infection of the meninges.
What is a CSF leak?A CSF leak occurs when the CSF escapes through a tear or hole in the dura, the outermost layer of the meninges. The dura can be injured or punctured by a head injury or surgical procedure involving the sinuses, brain or spine. It may also be damaged by a lumbar puncture, including a spinal tap, spinal anesthesia or myelogram. Spontaneous CSF leaks can occur due to increased intracranial pressure. This can happen to patients with hydrocephalus, a buildup of CSF in the skull. Spontaneous leaks may also occur without an identifiable cause.
CSF Leak Symptoms
Meningitis (bacterial or viral)
Nasal drainage of CSF (this may be difficult to distinguish from normal nasal discharge without specific tests)
Tinnitus (ringing in the ears)
Diagnosis of a CSF Leak
If your doctor suspects a CSF leak, he or she may recommend the following tests:
Analysis of the nasal fluid: This test is used to detect beta-2 transferrin,a protein found almost exclusively in CSF.
Pledget study: This simple test involves inserting pledgets (small cotton pads) into your nose. A pledget study can confirm the presence of CSF draining into the nose from the skull.
CT scan: This noninvasive diagnostic imaging procedure uses a combination of X-rays and computer technology to produce detailed imaging of bones and different planes of the brain.
MRI scan: This method combines a large magnet, radiofrequencies and a computer to produce detailed images of organs and structures within the body. MRI scans can help determine the location and severity of a CSF leak.
A myelogram is a scan that involves injecting a contrasting substance into the spinal cord and using MRI or CT scans to look for tears or ruptures in the dura.
A cisternogram involves injecting a radioactive medium into the spinal fluid through a spinal tap and then performing CT scans. This test may help identify the origin of the CSF leak in the tissues adjacent to the spine or into the nasal cavities.
CSF Leak Treatment
Because CSF leaks through the nose or ears increase of the risk of meningitis and other complications, in these situations the physician may recommend a CSF leak repair using endoscopic endonasal surgery or in rare cases, a craniotomy.
For CSF leaks that are draining into the spinal canal, there are other treatments, such as blood patches or fibrin patches. For these procedures, the physician uses CT guidance to inject a small amount of the patient’s own blood or a plug of fibrin (the fibrous protein in blood that helps it clot) into the spinal canal. This can often repair the leak.
If these methods fail, duraplasty—surgical repair of the dura—may be necessary.
For the best possible result, you should consult a team of neurosurgeons and other experts who are experienced in treating CSF leaks and other disorders involving CSF.
A Multidisciplinary Approach to Treating Spontaneous CSF Leaks
Physicians have long known that rising intracranial pressure may help create leaks. Now, a multidisciplinary team is developing protocols to better monitor rising pressures, especially in postsurgical patients.