Definition of CSF leak:

A CSF leak is an escape of the fluid that surrounds the brain and spinal cord.

Causes, incidence, and risk factors:

Any tear or hole in the membrane that surrounds the brain and spinal cord (dura) can allow the fluid that surrounds those organs to leak.

This fluid is called the cerebrospinal fluid (CSF). When it leaks out, the pressure around the brain and spinal cord drops.

Causes of leakage through the dura include:

• Certain head, brain, or spinal surgeries
• Head injury
• Placement of tubes for epidural anesthesia or pain medications
• Spinal tap (lumbar puncture)

Sometimes, no cause can be found. This is called a spontaneous CSF leak.