09/17/2026
When we talk about a CSF leak, location matters.
Is it a cranial CSF leak or a spinal CSF leak?
They can present very differently.
A spinal CSF leak often makes us think of the classic orthostatic headache — worse upright and better lying flat.
But a cranial leak happens around the skull base.
One clue can be a persistent clear, watery drip from one side of the nose, sometimes noticed more when bending or tilting the head forward. Some people describe a salty or metallic taste at the back of the throat.
Why?
A small defect in the skull base can allow cerebrospinal fluid — the fluid surrounding the brain — to escape into the nose.
But an important point:
A runny nose does not automatically mean a CSF leak.
Allergies and other nasal conditions are far more common.
It is persistent, unusually watery, often one-sided drainage — particularly when there has been head trauma, sinus/skull-base surgery or other concerning symptoms — that deserves investigation.
And interestingly, spontaneous cranial leaks can sometimes be associated with raised intracranial pressure, rather than the low-pressure picture we commonly associate with spinal leaks.
Same fluid.
Very different locations.
Very different clues.
You’ve probably never heard of a CSF leak — I hadn’t either, until I had one.
It’s when the brain fluid leaks, causing severe headaches that ease when lying flat. Many go years undiagnosed.
If you’re a healthcare professional, please repost.
Awareness saves lives. 💙